This patch widens SPI_processed, EState's es_processed field, PortalData's
portalPos field, FuncCallContext's call_cntr and max_calls fields,
ExecutorRun's count argument, PortalRunFetch's result, and the max number
of rows in a SPITupleTable to uint64, and deals with (I hope) all the
ensuing fallout. Some of these values were declared uint32 before, and
others "long".
I also removed PortalData's posOverflow field, since that logic seems
pretty useless given that portalPos is now always 64 bits.
The user-visible results are that command tags for SELECT etc will
correctly report tuple counts larger than 4G, as will plpgsql's GET
GET DIAGNOSTICS ... ROW_COUNT command. Queries processing more tuples
than that are still not exactly the norm, but they're becoming more
common.
Most values associated with FETCH/MOVE distances, such as PortalRun's count
argument and the count argument of most SPI functions that have one, remain
declared as "long". It's not clear whether it would be worth promoting
those to int64; but it would definitely be a large dollop of additional
API churn on top of this, and it would only help 32-bit platforms which
seem relatively less likely to see any benefit.
Andreas Scherbaum, reviewed by Christian Ullrich, additional hacking by me
CitusDB is using these and don't wish to redesign their code right now.
I am not on board with this being a good idea, or a good precedent,
but I lack the energy to fight about it.
Adds several tsvector editting function: convert tsvector to/from text array,
set weight for given lexemes, delete lexeme(s), unnest, filter lexemes
with given weights
Author: Stas Kelvich with some editorization by me
Reviewers: Tomas Vondram, Teodor Sigaev
Teach make_group_input_target() and make_window_input_target() to work
entirely with the PathTarget representation of tlists, rather than
constructing a tlist and immediately deconstructing it into PathTarget
format. In itself this only saves a few palloc's; the bigger picture is
that it opens the door for sharing cost_qual_eval work across all of
planner.c's constructions of PathTargets. I'll come back to that later.
In support of this, flesh out tlist.c's infrastructure for PathTargets
a bit more.
emit_log_hook could only see the translated text, making it harder to identify
which message was being sent. Pass original text to allow the exact message to
be identified, whichever language is used for logging.
Discussion: 20160216.184755.59721141.horiguchi.kyotaro@lab.ntt.co.jp
Author: Kyotaro Horiguchi
Up to now checkpoints were written in the order they're in the
BufferDescriptors. That's nearly random in a lot of cases, which
performs badly on rotating media, but even on SSDs it causes slowdowns.
To avoid that, sort checkpoints before writing them out. We currently
sort by tablespace, relfilenode, fork and block number.
One of the major reasons that previously wasn't done, was fear of
imbalance between tablespaces. To address that balance writes between
tablespaces.
The other prime concern was that the relatively large allocation to sort
the buffers in might fail, preventing checkpoints from happening. Thus
pre-allocate the required memory in shared memory, at server startup.
This particularly makes it more efficient to have checkpoint flushing
enabled, because that'll often result in a lot of writes that can be
coalesced into one flush.
Discussion: alpine.DEB.2.10.1506011320000.28433@sto
Author: Fabien Coelho and Andres Freund
Currently writes to the main data files of postgres all go through the
OS page cache. This means that some operating systems can end up
collecting a large number of dirty buffers in their respective page
caches. When these dirty buffers are flushed to storage rapidly, be it
because of fsync(), timeouts, or dirty ratios, latency for other reads
and writes can increase massively. This is the primary reason for
regular massive stalls observed in real world scenarios and artificial
benchmarks; on rotating disks stalls on the order of hundreds of seconds
have been observed.
On linux it is possible to control this by reducing the global dirty
limits significantly, reducing the above problem. But global
configuration is rather problematic because it'll affect other
applications; also PostgreSQL itself doesn't always generally want this
behavior, e.g. for temporary files it's undesirable.
Several operating systems allow some control over the kernel page
cache. Linux has sync_file_range(2), several posix systems have msync(2)
and posix_fadvise(2). sync_file_range(2) is preferable because it
requires no special setup, whereas msync() requires the to-be-flushed
range to be mmap'ed. For the purpose of flushing dirty data
posix_fadvise(2) is the worst alternative, as flushing dirty data is
just a side-effect of POSIX_FADV_DONTNEED, which also removes the pages
from the page cache. Thus the feature is enabled by default only on
linux, but can be enabled on all systems that have any of the above
APIs.
While desirable and likely possible this patch does not contain an
implementation for windows.
With the infrastructure added, writes made via checkpointer, bgwriter
and normal user backends can be flushed after a configurable number of
writes. Each of these sources of writes controlled by a separate GUC,
checkpointer_flush_after, bgwriter_flush_after and backend_flush_after
respectively; they're separate because the number of flushes that are
good are separate, and because the performance considerations of
controlled flushing for each of these are different.
A later patch will add checkpoint sorting - after that flushes from the
ckeckpoint will almost always be desirable. Bgwriter flushes are most of
the time going to be random, which are slow on lots of storage hardware.
Flushing in backends works well if the storage and bgwriter can keep up,
but if not it can have negative consequences. This patch is likely to
have negative performance consequences without checkpoint sorting, but
unfortunately so has sorting without flush control.
Discussion: alpine.DEB.2.10.1506011320000.28433@sto
Author: Fabien Coelho and Andres Freund
All along, this function should have treated WindowFuncs in a manner
similar to Aggrefs, ie with an option whether or not to recurse into them.
By not considering the case, it was always recursing, which is OK for most
callers (although I suspect that the case in prepare_sort_from_pathkeys
might represent a bug). But now we need return-without-recursing behavior
as well. There are also more than a few callers that should never see a
WindowFunc, and now we'll get some error checking on that.
In commit 1d97c19a0f and later c1d9579dd8, we extended
pull_var_clause's API by adding enum-type arguments. That's sort of a pain
to maintain, though, because it means every time we add a new behavior we
must touch every last one of the call sites, even if there's a reasonable
default behavior that most of them could use. Let's switch over to using a
bitmask of flags, instead; that seems more maintainable and might save a
nanosecond or two as well. This commit changes no behavior in itself,
though I'm going to follow it up with one that does add a new behavior.
In passing, remove flatten_tlist(), which has not been used since 9.1
and would otherwise need the same API changes.
Removing these enums means that optimizer/tlist.h no longer needs to
depend on optimizer/var.h. Changing that caused a number of C files to
need addition of #include "optimizer/var.h" (probably we can thank old
runs of pgrminclude for that); but on balance it seems like a good change
anyway.
Earlier version committed in 9.0 caused spurious waits in some cases.
New infrastructure for lock waits in 9.3 used to correct and improve this.
Jeff Janes based upon a proposal by Simon Riggs, who also reviewed
Additional review comments from Amit Kapila
When a process is waiting for a heavyweight lock, we will now indicate
the type of heavyweight lock for which it is waiting. Also, you can
now see when a process is waiting for a lightweight lock - in which
case we will indicate the individual lock name or the tranche, as
appropriate - or for a buffer pin.
Amit Kapila, Ildus Kurbangaliev, reviewed by me. Lots of helpful
discussion and suggestions by many others, including Alexander
Korotkov, Vladimir Borodin, and many others.
Renaming a file using rename(2) is not guaranteed to be durable in face
of crashes; especially on filesystems like xfs and ext4 when mounted
with data=writeback. To be certain that a rename() atomically replaces
the previous file contents in the face of crashes and different
filesystems, one has to fsync the old filename, rename the file, fsync
the new filename, fsync the containing directory. This sequence is not
generally adhered to currently; which exposes us to data loss risks. To
avoid having to repeat this arduous sequence, introduce
durable_rename(), which wraps all that.
Also add durable_link_or_rename(). Several places use link() (with a
fallback to rename()) to rename a file, trying to avoid replacing the
target file out of paranoia. Some of those rename sequences need to be
durable as well. There seems little reason extend several copies of the
same logic, so centralize the link() callers.
This commit does not yet make use of the new functions; they're used in
a followup commit.
Author: Michael Paquier, Andres Freund
Discussion: 56583BDD.9060302@2ndquadrant.com
Backpatch: All supported branches
Using this facility, any utility command can report the target relation
upon which it is operating, if there is one, and up to 10 64-bit
counters; the intent of this is that users should be able to figure out
what a utility command is doing without having to resort to ugly hacks
like attaching strace to a backend.
As a demonstration, this adds very crude reporting to lazy vacuum; we
just report the target relation and nothing else. A forthcoming patch
will make VACUUM report a bunch of additional data that will make this
much more interesting. But this gets the basic framework in place.
Vinayak Pokale, Rahila Syed, Amit Langote, Robert Haas, reviewed by
Kyotaro Horiguchi, Jim Nasby, Thom Brown, Masahiko Sawada, Fujii Masao,
and Masanori Oyama.
Refactor so that the internal APIs in planner.c deal in PathTargets not
targetlists, and establish a more regular structure for deriving the
targets needed for successive steps.
There is more that could be done here; calculating the eval costs of each
successive target independently is both inefficient and wrong in detail,
since we won't actually recompute values available from the input node's
tlist. But it's no worse than what happened before the pathification
rewrite. In any case this seems like a good starting point for considering
how to handle Konstantin Knizhnik's function-evaluation-postponement patch.
Instead of having planner.c compute a groupColIdx array and store it in
GroupingSetsPaths, make create_groupingsets_plan() find the grouping
columns by searching in the child plan node's tlist. Although that's
probably a bit slower for create_groupingsets_plan(), it's more like
the way every other plan node type does this, and it provides positive
confirmation that we know which child output columns we're supposed to be
grouping on. (Indeed, looking at this now, I'm not at all sure that it
wasn't broken before, because create_groupingsets_plan() isn't demanding
an exact tlist match from its child node.) Also, this allows substantial
simplification in planner.c, because it no longer needs to compute the
groupColIdx array at all; no other cases were using it.
I'd intended to put off this refactoring until later (like 9.7), but
in view of the likely bug fix and the need to rationalize planner.c's
tlist handling so we can do something sane with Konstantin Knizhnik's
function-evaluation-postponement patch, I think it can't wait.
This patch removes some redundant cost calculations that I left for later
cleanup in commit 3fc6e2d7f5. There's now a uniform policy that the
make_foo() convenience functions don't do any cost calculations. Most of
their callers copy costs from the source Path node, and for those that
don't, the calculation in the make_foo() function wasn't necessarily right
anyhow. (make_result() was particularly a mess, as it was serving multiple
callers using cost calcs designed for only the first one or two that had
ever existed.) Aside from saving a few cycles, this ensures that what
EXPLAIN prints matches the costs we used for planning purposes. It does
not change any planner decisions, since the decisions are already made.
For example, if you want to perform an ioctl() on a file descriptor
opened through the fd.c routines, there's no way to do that without
being able to get at the underlying fd.
KaiGai Kohei
Commit a892234f83 added a second bit per
page to the visibility map, which still seems like a good idea, but it
also added a second page-level bit alongside PD_ALL_VISIBLE to track
whether the visibility map bit was set. That no longer seems like a
clever plan, because we don't really need that bit for anything. We
always clear both bits when the page is modified anyway.
Patch by me, reviewed by Kyotaro Horiguchi and Masahiko Sawada.
I've been saying we needed to do this for more than five years, and here it
finally is. This patch removes the ever-growing tangle of spaghetti logic
that grouping_planner() used to use to try to identify the best plan for
post-scan/join query steps. Now, there is (nearly) independent
consideration of each execution step, and entirely separate construction of
Paths to represent each of the possible ways to do that step. We choose
the best Path or set of Paths using the same add_path() logic that's been
used inside query_planner() for years.
In addition, this patch removes the old restriction that subquery_planner()
could return only a single Plan. It now returns a RelOptInfo containing a
set of Paths, just as query_planner() does, and the parent query level can
use each of those Paths as the basis of a SubqueryScanPath at its level.
This allows finding some optimizations that we missed before, wherein a
subquery was capable of returning presorted data and thereby avoiding a
sort in the parent level, making the overall cost cheaper even though
delivering sorted output was not the cheapest plan for the subquery in
isolation. (A couple of regression test outputs change in consequence of
that. However, there is very little change in visible planner behavior
overall, because the point of this patch is not to get immediate planning
benefits but to create the infrastructure for future improvements.)
There is a great deal left to do here. This patch unblocks a lot of
planner work that was basically impractical in the old code structure,
such as allowing FDWs to implement remote aggregation, or rewriting
plan_set_operations() to allow consideration of multiple implementation
orders for set operations. (The latter will likely require a full
rewrite of plan_set_operations(); what I've done here is only to fix it
to return Paths not Plans.) I have also left unfinished some localized
refactoring in createplan.c and planner.c, because it was not necessary
to get this patch to a working state.
Thanks to Robert Haas, David Rowley, and Amit Kapila for review.
When decoding the old version of an UPDATE or DELETE change, and if that
tuple was bigger than MaxHeapTupleSize, we either Assert'ed out, or
failed in more subtle ways in non-assert builds. Normally individual
tuples aren't bigger than MaxHeapTupleSize, with big datums toasted.
But that's not the case for the old version of a tuple for logical
decoding; the replica identity is logged as one piece. With the default
replica identity btree limits that to small tuples, but that's not the
case for FULL.
Change the tuple buffer infrastructure to separate allocate over-large
tuples, instead of always going through the slab cache.
This unfortunately requires changing the ReorderBufferTupleBuf
definition, we need to store the allocated size someplace. To avoid
requiring output plugins to recompile, don't store HeapTupleHeaderData
directly after HeapTupleData, but point to it via t_data; that leaves
rooms for the allocated size. As there's no reason for an output plugin
to look at ReorderBufferTupleBuf->t_data.header, remove the field. It
was just a minor convenience having it directly accessible.
Reported-By: Adam Dratwiński
Discussion: CAKg6ypLd7773AOX4DiOGRwQk1TVOQKhNwjYiVjJnpq8Wo+i62Q@mail.gmail.com
Logical decoding's reorderbuffer keeps transactions in an LSN ordered
list for efficiency. To make that's efficiently possible upper-level
xids are forced to be logged before nested subtransaction xids. That
only works though if these records are all looked at: Unfortunately we
didn't do so for e.g. row level locks, which are otherwise uninteresting
for logical decoding.
This could lead to errors like:
"ERROR: subxact logged without previous toplevel record".
It's not sufficient to just look at row locking records, the xid could
appear first due to a lot of other types of records (which will trigger
the transaction to be marked logged with MarkCurrentTransactionIdLoggedIfAny).
So invent infrastructure to tell reorderbuffer about xids seen, when
they'd otherwise not pass through reorderbuffer.c.
Reported-By: Jarred Ward
Bug: #13844
Discussion: 20160105033249.1087.66040@wrigleys.postgresql.org
Backpatch: 9.4, where logical decoding was added
Add four new SQL accessible functions: pg_control_system(),
pg_control_checkpoint(), pg_control_recovery(), and pg_control_init()
which expose a subset of the control file data.
Along the way move the code to read and validate the control file to
src/common, where it can be shared by the new backend functions
and the original pg_controldata frontend program.
Patch by me, significant input, testing, and review by Michael Paquier.
Now it's possible to load recent version of Hunspell for several languages.
To handle these dictionaries Hunspell patch adds support for:
* FLAG long - sets the double extended ASCII character flag type
* FLAG num - sets the decimal number flag type (from 1 to 65535)
* AF parameter - alias for flag's set
Also it moves test dictionaries into separate directory.
Author: Artur Zakirov with editorization by me
606c0123d6 attempted to reduce cost of index scans using > and <
strategies, though got that completely wrong in a few complex cases.
Revert whole patch until we find a safe optimization.
Commits 9ff60273e3 and dbe2328959 adjusted the declarations
of some core functions referenced by contrib/tsearch2's install script,
forgetting that in a pg_upgrade situation, we'll be trying to restore
operator class definitions that reference the old signatures. We've
hit this problem before; solve it in the same way as before, namely by
installing stub functions that have the expected signature and just
invoke the correct function. Per report from Jeff Janes.
(Someday we ought to stop supporting contrib/tsearch2, but I'm not
sure today is that day.)
The new bit indicates whether every tuple on the page is already frozen.
It is cleared only when the all-visible bit is cleared, and it can be
set only when we vacuum a page and find that every tuple on that page is
both visible to every transaction and in no need of any future
vacuuming.
A future commit will use this new bit to optimize away full-table scans
that would otherwise be triggered by XID wraparound considerations. A
page which is merely all-visible must still be scanned in that case, but
a page which is all-frozen need not be. This commit does not attempt
that optimization, although that optimization is the goal here. It
seems better to get the basic infrastructure in place first.
Per discussion, it's very desirable for pg_upgrade to automatically
migrate existing VM forks from the old format to the new format. That,
too, will be handled in a follow-on patch.
Masahiko Sawada, reviewed by Kyotaro Horiguchi, Fujii Masao, Amit
Kapila, Simon Riggs, Andres Freund, and others, and substantially
revised by me.
This is basically a bug fix; the old code assumes that a ForeignScan
is always parallel-safe, but for postgres_fdw, for example, this is
definitely false. It should be true for file_fdw, though, since a
worker can read a file from the filesystem just as well as any other
backend process.
Original patch by Thomas Munro. Documentation, and changes to the
comments, by me.
This patch introduces "pg_blocking_pids(int) returns int[]", which returns
the PIDs of any sessions that are blocking the session with the given PID.
Historically people have obtained such information using a self-join on
the pg_locks view, but it's unreasonably tedious to do it that way with any
modicum of correctness, and the addition of parallel queries has pretty
much broken that approach altogether. (Given some more columns in the view
than there are today, you could imagine handling parallel-query cases with
a 4-way join; but ugh.)
The new function has the following behaviors that are painful or impossible
to get right via pg_locks:
1. Correctly understands which lock modes block which other ones.
2. In soft-block situations (two processes both waiting for conflicting lock
modes), only the one that's in front in the wait queue is reported to
block the other.
3. In parallel-query cases, reports all sessions blocking any member of
the given PID's lock group, and reports a session by naming its leader
process's PID, which will be the pg_backend_pid() value visible to
clients.
The motivation for doing this right now is mostly to fix the isolation
tests. Commit 38f8bdcac4 lobotomized
isolationtester's is-it-waiting query by removing its ability to recognize
nonconflicting lock modes, as a crude workaround for the inability to
handle soft-block situations properly. But even without the lock mode
tests, the old query was excessively slow, particularly in
CLOBBER_CACHE_ALWAYS builds; some of our buildfarm animals fail the new
deadlock-hard test because the deadlock timeout elapses before they can
probe the waiting status of all eight sessions. Replacing the pg_locks
self-join with use of pg_blocking_pids() is not only much more correct, but
a lot faster: I measure it at about 9X faster in a typical dev build with
Asserts, and 3X faster in CLOBBER_CACHE_ALWAYS builds. That should provide
enough headroom for the slower CLOBBER_CACHE_ALWAYS animals to pass the
test, without having to lengthen deadlock_timeout yet more and thus slow
down the test for everyone else.
We don't really need this field, because it's either zero or redundant with
PGPROC.pid. The use of zero to mark "not a group leader" is not necessary
since we can just as well test whether lockGroupLeader is NULL. This does
not save very much, either as to code or data, but the simplification seems
worthwhile anyway.
Coverity griped about use of unchecked strcpy() into a local variable.
There's unlikely to be any actual bug there, since no caller would be
passing a path longer than MAXPGPATH, but nonetheless use of strlcpy()
seems preferable.
While at it, get rid of unmaintainable separation between list of
field names and list of field values in favor of initializing them
in parallel. And we might as well declare get_configdata()'s path
argument as const char *, even though no current caller needs that.
Reflow text in lock manager README so that it fits within 80 columns.
Correct some mistakes. Expand the README to explain not only why group
locking exists but also the data structures that support it. Improve
comments related to group locking several files. Change the name of a
macro argument for improved clarity.
Most of these problems were reported by Tom Lane, but I found a few
of them myself.
Robert Haas and Tom Lane
This will parse strings in the format produced by pg_size_pretty() and
return sizes in bytes. This allows queries to be written with clauses
like "pg_total_relation_size(oid) > pg_size_bytes('10 GB')".
Author: Pavel Stehule with various improvements by Vitaly Burovoy
Discussion: http://www.postgresql.org/message-id/CAFj8pRD-tGoDKnxdYgECzA4On01_uRqPrwF-8LdkSE-6bDHp0w@mail.gmail.com
Reviewed-by: Vitaly Burovoy, Oleksandr Shulgin, Kyotaro Horiguchi,
Michael Paquier and Robert Haas
Architecture reference material specifies this order, and s_lock.h
inline assembly agrees. The former order failed to provide mutual
exclusion to lwlock.c and perhaps to other clients. The two xlc
buildfarm members, hornet and mandrill, have failed sixteen times with
duplicate key errors involving pg_class_oid_index or pg_type_oid_index.
Back-patch to 9.5, where commit b64d92f1a5
introduced atomics.
Reviewed by Andres Freund and Tom Lane.
Up to now, there's been an assumption that all Paths for a given relation
compute the same output column set (targetlist). However, there are good
reasons to remove that assumption. For example, an indexscan on an
expression index might be able to return the value of an expensive function
"for free". While we have the ability to generate such a plan today in
simple cases, we don't have a way to model that it's cheaper than a plan
that computes the function from scratch, nor a way to create such a plan
in join cases (where the function computation would normally happen at
the topmost join node). Also, we need this so that we can have Paths
representing post-scan/join steps, where the targetlist may well change
from one step to the next. Therefore, invent a "struct PathTarget"
representing the columns we expect a plan step to emit. It's convenient
to include the output tuple width and tlist evaluation cost in this struct,
and there will likely be additional fields in future.
While Path nodes that actually do have custom outputs will need their own
PathTargets, it will still be true that most Paths for a given relation
will compute the same tlist. To reduce the overhead added by this patch,
keep a "default PathTarget" in RelOptInfo, and allow Paths that compute
that column set to just point to their parent RelOptInfo's reltarget.
(In the patch as committed, actually every Path is like that, since we
do not yet have any cases of custom PathTargets.)
I took this opportunity to provide some more-honest costing of
PlaceHolderVar evaluation. Up to now, the assumption that "scan/join
reltargetlists have cost zero" was applied not only to Vars, where it's
reasonable, but also PlaceHolderVars where it isn't. Now, we add the eval
cost of a PlaceHolderVar's expression to the first plan level where it can
be computed, by including it in the PathTarget cost field and adding that
to the cost estimates for Paths. This isn't perfect yet but it's much
better than before, and there is a way forward to improve it more. This
costing change affects the join order chosen for a couple of the regression
tests, changing expected row ordering.
Move and refactor the underlying code for the pg_config client
application to src/common in support of sharing it with a new
system information SRF called pg_config() which makes the same
information available via SQL. Additionally wrap the SRF with a
new system view, as called pg_config.
Patch by me with extensive input and review by Michael Paquier
and additional review by Alvaro Herrera.
When processing ordered aggregates following a sort that could make use
of the abbreviated key optimization, only call the equality operator to
compare successive pairs of tuples when their abbreviated keys were not
equal.
Peter Geoghegan, reviewd by Andreas Karlsson and by me.
In commit 7b4bfc87 the DATA and DESCR entries for the new
row_security_active() function were inadvertantly put after
the PROVOLATILE defines, rather than before as they should
have been placed. Move them up where they belong.
Backpatch to 9.5 where the new entries were introduced.
Commit 4de82f7d7 increased the WAL flush rate, mainly to increase the
likelihood that hint bits can be set quickly. More quickly set hint bits
can reduce contention around the clog et al. But unfortunately the
increased flush rate can have a significant negative performance impact,
I have measured up to a factor of ~4. The reason for this slowdown is
that if there are independent writes to the underlying devices, for
example because shared buffers is a lot smaller than the hot data set,
or because a checkpoint is ongoing, the fdatasync() calls force cache
flushes to be emitted to the storage.
This is achieved by flushing WAL only if the last flush was longer than
wal_writer_delay ago, or if more than wal_writer_flush_after (new GUC)
unflushed blocks are pending. Based on some tests the default for
wal_writer_delay is 1MB, which seems to work well both on SSD and
rotational media.
To avoid negative performance impact due to 4de82f7d7 an earlier
commit (db76b1e) made SetHintBits() more likely to succeed; preventing
performance regressions in the pgbench tests I performed.
Discussion: 20160118163908.GW10941@awork2.anarazel.de
Reportedly, some compilers warn about tests like "c < 0" if c is unsigned,
and hence complain about the character range checks I added in commit
3bb3f42f37. This is a bit of a pain since
the regex library doesn't really want to assume that chr is unsigned.
However, since any such reconfiguration would involve manual edits of
regcustom.h anyway, we can put it on the shoulders of whoever wants to
do that to adjust this new range-checking macro correctly.
Per gripes from Coverity and Andres.
An extensible node is always tagged T_Extensible, but the extnodename
field identifies it more specifically; it may also include arbitrary
private data. Extensible nodes can be copied, tested for equality,
serialized, and deserialized, but the core system doesn't know
anything about them otherwise. Some extensions may find it useful to
include these nodes in fdw_private or custom_private lists in lieu of
arm-wrestling their data into a format that the core code can
understand.
Along the way, so as not to burden the authors of such extensible
node types too much, expose the functions for writing serialized
tokens, and for serializing and deserializing bitmapsets.
KaiGai Kohei, per a design suggested by me. Reviewed by Andres Freund
and by me, and further edited by me.
If a GROUP BY clause includes all columns of a non-deferred primary key,
as well as other columns of the same relation, those other columns are
redundant and can be dropped from the grouping; the pkey is enough to
ensure that each row of the table corresponds to a separate group.
Getting rid of the excess columns will reduce the cost of the sorting or
hashing needed to implement GROUP BY, and can indeed remove the need for
a sort step altogether.
This seems worth testing for since many query authors are not aware of
the GROUP-BY-primary-key exception to the rule about queries not being
allowed to reference non-grouped-by columns in their targetlists or
HAVING clauses. Thus, redundant GROUP BY items are not uncommon. Also,
we can make the test pretty cheap in most queries where it won't help
by not looking up a rel's primary key until we've found that at least
two of its columns are in GROUP BY.
David Rowley, reviewed by Julien Rouhaud
A pending patch requires exporting a function returning Bitmapset from
catalog/pg_constraint.c. As things stand, that would mean including
nodes/bitmapset.h in pg_constraint.h, which might be hazardous for the
client-side includability of that header. It's not entirely clear whether
any client-side code needs to include pg_constraint.h, but it seems prudent
to assume that there is some such code somewhere. Therefore, split off the
function definitions into a new file pg_constraint_fn.h, similarly to what
we've done for some other catalog header files.
This finishes the work - spread across many commits over the last
several months - of putting each type of lock other than the named
individual locks into a separate tranche.
Amit Kapila
Commit 0e141c0fbb introduced a new
facility to reduce ProcArrayLock contention by clearing several XIDs
from the ProcArray under a single lock acquisition. The names
initially chosen were deemed not to be very good choices, so commit
4aec49899e renamed them. But now it
seems like we still didn't get it right. A pending patch wants to
add similar infrastructure for batching CLOG updates, so the names
need to be clear enough to allow a new set of structure members with
a related purpose.
Amit Kapila
As of commit c1772ad922, there's no
longer any way of requesting additional LWLocks in the main tranche,
so we don't need NumLWLocks() or LWLockAssign() any more. Also,
some of the allocation counters that we had previously aren't needed
any more either.
Amit Kapila
This is a quick hack, due to be reverted when its purpose has been served,
to try to gather information about why some of the buildfarm critters
regularly fail with "postmaster does not shut down" complaints. Maybe they
are just really overloaded, but maybe something else is going on. Hence,
instrument pg_ctl to print the current time when it starts waiting for
postmaster shutdown and when it gives up, and add a lot of logging of the
current time in the server's checkpoint and shutdown code paths.
No attempt has been made to make this pretty. I'm not even totally sure
if it will build on Windows, but we'll soon find out.
Previously, our regex code defined CHR_MAX as 0xfffffffe, which is a
bad choice because it is outside the range of type "celt" (int32).
Characters approaching that limit could lead to infinite loops in logic
such as "for (c = a; c <= b; c++)" where c is of type celt but the
range bounds are chr. Such loops will work safely only if CHR_MAX+1
is representable in celt, since c must advance to beyond b before the
loop will exit.
Fortunately, there seems no reason not to restrict CHR_MAX to 0x7ffffffe.
It's highly unlikely that Unicode will ever assign codes that high, and
none of our other backend encodings need characters beyond that either.
In addition to modifying the macro, we have to explicitly enforce character
range restrictions on the values of \u, \U, and \x escape sequences, else
the limit is trivially bypassed.
Also, the code for expanding case-independent character ranges in bracket
expressions had a potential integer overflow in its calculation of the
number of characters it could generate, which could lead to allocating too
small a character vector and then overwriting memory. An attacker with the
ability to supply arbitrary regex patterns could easily cause transient DOS
via server crashes, and the possibility for privilege escalation has not
been ruled out.
Quite aside from the integer-overflow problem, the range expansion code was
unnecessarily inefficient in that it always produced a result consisting of
individual characters, abandoning the knowledge that we had a range to
start with. If the input range is large, this requires excessive memory.
Change it so that the original range is reported as-is, and then we add on
any case-equivalent characters that are outside that range. With this
approach, we can bound the number of individual characters allowed without
sacrificing much. This patch allows at most 100000 individual characters,
which I believe to be more than the number of case pairs existing in
Unicode, so that the restriction will never be hit in practice.
It's still possible for range() to take awhile given a large character code
range, so also add statement-cancel detection to its loop. The downstream
function dovec() also lacked cancel detection, and could take a long time
given a large output from range().
Per fuzz testing by Greg Stark. Back-patch to all supported branches.
Security: CVE-2016-0773
When force_parallel_mode = true, we enable the parallel mode restrictions
for all queries for which this is believed to be safe. For the subset of
those queries believed to be safe to run entirely within a worker, we spin
up a worker and run the query there instead of running it in the
original process. When force_parallel_mode = regress, make additional
changes to allow the regression tests to run cleanly even though parallel
workers have been injected under the hood.
Taken together, this facilitates both better user testing and better
regression testing of the parallelism code.
Robert Haas, with help from Amit Kapila and Rushabh Lathia.
For locking purposes, we now regard heavyweight locks as mutually
non-conflicting between cooperating parallel processes. There are some
possible pitfalls to this approach that are not to be taken lightly,
but it works OK for now and can be changed later if we find a better
approach. Without this, it's very easy for parallel queries to
silently self-deadlock if the user backend holds strong relation locks.
Robert Haas, with help from Amit Kapila. Thanks to Noah Misch and
Andres Freund for extensive discussion of possible issues with this
approach.
It seems that sprintf(), at least in glibc's version, is unreasonably slow
compared to hand-rolled code for printing integers. Replacing most uses of
sprintf() in the datetime.c output functions with special-purpose code
turns out to give more than a 2X speedup in COPY of a table with a single
timestamp column; which is pretty impressive considering all the other
logic in that code path.
David Rowley and Andres Freund, reviewed by Peter Geoghegan and myself
An example use-case is "CHECK(num_nonnulls(a,b,c) = 1)" to assert that
exactly one of a,b,c isn't NULL. The functions are variadic, so they
can also be pressed into service to count the number of null or nonnull
elements in an array.
Marko Tiikkaja, reviewed by Pavel Stehule
GetExistingLocalJoinPath() is useful for handling EvalPlanQual rechecks
properly, and GetUserMappingById() is needed to make sure you're using
the right credentials.
Shigeru Hanada, Etsuro Fujita, Ashutosh Bapat, Robert Haas
The previous RequestAddinLWLocks() method had several disadvantages.
First, the locks would be in the main tranche; we've recently decided
that it's useful for LWLocks used for separate purposes to have
separate tranche IDs. Second, there wasn't any correlation between
what code called RequestAddinLWLocks() and what code called
LWLockAssign(); when multiple modules are in use, it could become
quite difficult to troubleshoot problems where LWLockAssign() ran out
of locks. To fix, create a concept of named LWLock tranches which
can be used either by extension or by core code.
Amit Kapila and Robert Haas
Have varlena.c expose an interface that allows the char(n), bytea, and
bpchar types to piggyback on a now-generalized SortSupport for text.
This pushes a little more knowledge of the bpchar/char(n) type into
varlena.c than might be preferred, but that seems like the approach
that creates least friction. Also speed things up for index builds
that use text_pattern_ops or varchar_pattern_ops.
This patch does quite a bit of renaming, but it seems likely to be
worth it, so as to avoid future confusion about the fact that this code
is now more generally used than the old names might have suggested.
Peter Geoghegan, reviewed by Álvaro Herrera and Andreas Karlsson,
with small tweaks by me.
This patch doesn't put the new infrastructure to use anywhere, and
indeed it's not clear how it could ever be used for something like
postgres_fdw which has to send an SQL query and wait for a reply,
but there might be FDWs or custom scan providers that are CPU-bound,
so let's give them a way to join club parallel.
KaiGai Kohei, reviewed by me.
You can't really do anything useful with this in the form it currently
exists; among other problems, there's no way to reread whatever
information might be produced when the path is output. Work is
underway to replace this with a more useful and more general system of
extensible nodes, but let's start by getting rid of this bit.
Extracted from a larger patch by KaiGai Kohei.
Insert sd_notify() calls at server start and stop for integration with
systemd. This allows the use of systemd service units of type "notify",
which greatly simplifies the systemd configuration.
Reviewed-by: Pavel Stěhule <pavel.stehule@gmail.com>
Apparently at least one committer hasn't gotten the word that these do not
need to be maintained by hand, since initdb will create them automatically.
Noted while fixing bug #13905.
No catversion bump since the post-initdb state is exactly the same either
way. I don't see a need for back-patch, either.
All the other jsonb function descriptions refer to the arguments as being
"jsonb", but these two said "json". Make it consistent. Per bug #13905
from Petru Florin Mihancea.
No catversion bump --- we can't force one in the back branches, and this
isn't very critical anyway.
This is following in a long train of similar changes and for the same
reasons - see b319356f0e and
fe702a7b3f inter alia.
Author: Amit Kapila
Reviewed-by: Alexander Korotkov, Robert Haas
Previously, each PGPROC's backendLock was part of the main tranche,
and the PGPROC just contained a pointer. Now, the actual LWLock is
part of the PGPROC.
As with previous, similar patches, this makes it significantly easier
to identify these lwlocks in LWLOCK_STATS or Trace_lwlocks output
and improves modularity.
Author: Ildus Kurbangaliev
Reviewed-by: Amit Kapila, Robert Haas
Previously, the foreign join pushdown infrastructure left the question
of security entirely up to individual FDWs, but it would be easy for
a foreign data wrapper to inadvertently open up subtle security holes
that way. So, make it the core code's job to determine which user
mapping OID is relevant, and don't attempt join pushdown unless it's
the same for all relevant relations.
Per a suggestion from Tom Lane. Shigeru Hanada and Ashutosh Bapat,
reviewed by Etsuro Fujita and KaiGai Kohei, with some further
changes by me.
Previously, postgres_fdw's connection cache was keyed by user OID and
server OID, but this can lead to multiple connections when it's not
really necessary. In particular, if all relevant users are mapped to
the public user mapping, then their connection options are certainly
the same, so one connection can be used for all of them.
While we're cleaning things up here, drop the "server" argument to
GetConnection(), which isn't really needed. This saves a few cycles
because callers no longer have to look this up; the function itself
does, but only when establishing a new connection, not when reusing
an existing one.
Ashutosh Bapat, with a few small changes by me.
This function cleans up the pending list of the GIN index by
moving entries in it to the main GIN data structure in bulk.
It returns the number of pages cleaned up from the pending list.
This function is useful, for example, when the pending list
needs to be cleaned up *quickly* to improve the performance of
the search using GIN index. VACUUM can do the same thing, too,
but it may take days to run on a large table.
Jeff Janes,
reviewed by Julien Rouhaud, Jaime Casanova, Alvaro Herrera and me.
Discussion: CAMkU=1x8zFkpfnozXyt40zmR3Ub_kHu58LtRmwHUKRgQss7=iQ@mail.gmail.com
pg_size_pretty function should be marked immutable rather than volatile
because it always returns the same result given the same argument.
Pavel Stehule
The implementations go to some lengths to deliver exact results for values
where an exact result can be expected, such as sind(30) = 0.5 exactly.
Dean Rasheed, reviewed by Michael Paquier
Commit e529cd4ffa introduced an Assert requiring NAMEDATALEN to be
less than MAX_LEVENSHTEIN_STRLEN, which has been 255 for a long time.
Since up to that instant we had always allowed NAMEDATALEN to be
substantially more than that, this was ill-advised.
It's debatable whether we need MAX_LEVENSHTEIN_STRLEN at all (versus
putting a CHECK_FOR_INTERRUPTS into the loop), or whether it has to be
so tight; but this patch takes the narrower approach of just not applying
the MAX_LEVENSHTEIN_STRLEN limit to calls from the parser.
Trusting the parser for this seems reasonable, first because the strings
are limited to NAMEDATALEN which is unlikely to be hugely more than 256,
and second because the maximum distance is tightly constrained by
MAX_FUZZY_DISTANCE (though we'd forgotten to make use of that limit in one
place). That means the cost is not really O(mn) but more like O(max(m,n)).
Relaxing the limit for user-supplied calls is left for future research;
given the lack of complaints to date, it doesn't seem very high priority.
In passing, fix confusion between lengths-in-bytes and lengths-in-chars
in comments and error messages.
Per gripe from Kevin Day; solution suggested by Robert Haas. Back-patch
to 9.5 where the unwanted restriction was introduced.
The amvalidate functions added in commit 65c5fcd353 were on the
crude side. Improve them in a few ways:
* Perform signature checking for operators and support functions.
* Apply more thorough checks for missing operators and functions,
where possible.
* Instead of reporting problems as ERRORs, report most problems as INFO
messages and make the amvalidate function return FALSE. This allows
more than one problem to be discovered per run.
* Report object names rather than OIDs, and work a bit harder on making
the messages understandable.
Also, remove a few more opr_sanity regression test queries that are
now superseded by the amvalidate checks.
Putting a reference to an expanded-format value into a Const node would be
a bad idea for a couple of reasons. It'd be possible for the supposedly
immutable Const to change value, if something modified the referenced
variable ... in fact, if the Const's reference were R/W, any function that
has the Const as argument might itself change it at runtime. Also, because
datumIsEqual() is pretty simplistic, the Const might fail to compare equal
to other Consts that it should compare equal to, notably including copies
of itself. This could lead to unexpected planner behavior, such as "could
not find pathkey item to sort" errors or inferior plans.
I have not been able to find any way to get an expanded value into a Const
within the existing core code; but Paul Ramsey was able to trigger the
problem by writing a datatype input function that returns an expanded
value.
The best fix seems to be to establish a rule that varlena values being
placed into Const nodes should be passed through pg_detoast_datum().
That will do nothing (and cost little) in normal cases, but it will flatten
expanded values and thereby avoid the above problems. Also, it will
convert short-header or compressed values into canonical format, which will
avoid possible unexpected lack-of-equality issues for those cases too.
And it provides a last-ditch defense against putting a toasted value into
a Const, which we already knew was dangerous, cf commit 2b0c86b665.
(In the light of this discussion, I'm no longer sure that that commit
provided 100% protection against such cases, but this fix should do it.)
The test added in commit 65c3d05e18 to catch datatype input functions
with unstable results would fail for functions that returned expanded
values; but it seems a bit uncharitable to deem a result unstable just
because it's expressed in expanded form, so revise the coding so that we
check for bitwise equality only after applying pg_detoast_datum(). That's
a sufficient condition anyway given the new rule about detoasting when
forming a Const.
Back-patch to 9.5 where the expanded-object facility was added. It's
possible that this should go back further; but in the absence of clear
evidence that there's any live bug in older branches, I'll refrain for now.
2PC state info is written only to WAL at PREPARE, then read back from WAL at
COMMIT PREPARED/ABORT PREPARED. Prepared transactions that live past one bufmgr
checkpoint cycle will be written to disk in the same form as previously. Crash
recovery path is not altered. Measured performance gains of 50-100% for short
2PC transactions by completely avoiding writing files and fsyncing. Other
optimizations still available, further patches in related areas expected.
Stas Kelvich and heavily edited by Simon Riggs
Based upon earlier ideas and patches by Michael Paquier and Heikki Linnakangas,
a concrete example of how Postgres-XC has fed back ideas into PostgreSQL.
Reviewed by Michael Paquier, Jeff Janes and Andres Freund
Performance testing by Jesper Pedersen
Previously we didn’t have a generic WAL page read callback function,
surprisingly. Logical decoding has logical_read_local_xlog_page(), which was
actually generic, so move that to xlogfunc.c and rename to
read_local_xlog_page().
Maintain logical_read_local_xlog_page() so existing callers still work.
As requested by Michael Paquier, Alvaro Herrera and Andres Freund
The core innovation of this patch is the introduction of the concept
of a partial path; that is, a path which if executed in parallel will
generate a subset of the output rows in each process. Gathering a
partial path produces an ordinary (complete) path. This allows us to
generate paths for parallel joins by joining a partial path for one
side (which at the baserel level is currently always a Partial Seq
Scan) to an ordinary path on the other side. This is subject to
various restrictions at present, especially that this strategy seems
unlikely to be sensible for merge joins, so only nested loops and
hash joins paths are generated.
This also allows an Append node to be pushed below a Gather node in
the case of a partitioned table.
Testing revealed that early versions of this patch made poor decisions
in some cases, which turned out to be caused by the fact that the
original cost model for Parallel Seq Scan wasn't very good. So this
patch tries to make some modest improvements in that area.
There is much more to be done in the area of generating good parallel
plans in all cases, but this seems like a useful step forward.
Patch by me, reviewed by Dilip Kumar and Amit Kapila.
Aggregate nodes now have two new modes: a "partial" mode where they
output the unfinalized transition state, and a "finalize" mode where
they accept unfinalized transition states rather than individual
values as input.
These new modes are not used anywhere yet, but they will be necessary
for parallel aggregation. The infrastructure also figures to be
useful for cases where we want to aggregate local data and remote
data via the FDW interface, and want to bring back partial aggregates
from the remote side that can then be combined with locally generated
partial aggregates to produce the final value. It may also be useful
even when neither FDWs nor parallelism are in play, as explained in
the comments in nodeAgg.c.
David Rowley and Simon Riggs, reviewed by KaiGai Kohei, Heikki
Linnakangas, Haribabu Kommi, and me.
GIN had some minor issues too, mostly using "internal" where something
else would be more appropriate. I went with the same approach as in
9ff60273e3, namely preferring the opclass' indexed datatype for
arguments that receive an operator RHS value, even if that's not
necessarily what they really are.
Again, this is with an eye to having a uniform rule for ginvalidate()
to check support function signatures.
The conventions specified by the GiST SGML documentation were widely
ignored. For example, the strategy-number argument for "consistent" and
"distance" functions is specified to be a smallint, but most of the
built-in support functions declared it as an integer, and for that matter
the core code passed it using Int32GetDatum not Int16GetDatum. None of
that makes any real difference at runtime, but it's quite confusing for
newcomers to the code, and it makes it very hard to write an amvalidate()
function that checks support function signatures. So let's try to instill
some consistency here.
Another similar issue is that the "query" argument is not of a single
well-defined type, but could have different types depending on the strategy
(corresponding to search operators with different righthand-side argument
types). Some of the functions threw up their hands and declared the query
argument as being of "internal" type, which surely isn't right ("any" would
have been more appropriate); but the majority position seemed to be to
declare it as being of the indexed data type, corresponding to a search
operator with both input types the same. So I've specified a convention
that that's what to do always.
Also, the result of the "union" support function actually must be of the
index's storage type, but the documentation suggested declaring it to
return "internal", and some of the functions followed that. Standardize
on telling the truth, instead.
Similarly, standardize on declaring the "same" function's inputs as
being of the storage type, not "internal".
Also, somebody had forgotten to add the "recheck" argument to both
the documentation of the "distance" support function and all of their
SQL declarations, even though the C code was happily using that argument.
Clean that up too.
Fix up some other omissions in the docs too, such as documenting that
union's second input argument is vestigial.
So far as the errors in core function declarations go, we can just fix
pg_proc.h and bump catversion. Adjusting the erroneous declarations in
contrib modules is more debatable: in principle any change in those
scripts should involve an extension version bump, which is a pain.
However, since these changes are purely cosmetic and make no functional
difference, I think we can get away without doing that.
This patch reduces pg_am to just two columns, a name and a handler
function. All the data formerly obtained from pg_am is now provided
in a C struct returned by the handler function. This is similar to
the designs we've adopted for FDWs and tablesample methods. There
are multiple advantages. For one, the index AM's support functions
are now simple C functions, making them faster to call and much less
error-prone, since the C compiler can now check function signatures.
For another, this will make it far more practical to define index access
methods in installable extensions.
A disadvantage is that SQL-level code can no longer see attributes
of index AMs; in particular, some of the crosschecks in the opr_sanity
regression test are no longer possible from SQL. We've addressed that
by adding a facility for the index AM to perform such checks instead.
(Much more could be done in that line, but for now we're content if the
amvalidate functions more or less replace what opr_sanity used to do.)
We might also want to expose some sort of reporting functionality, but
this patch doesn't do that.
Alexander Korotkov, reviewed by Petr Jelínek, and rather heavily
editorialized on by me.
A scan for missed proisstrict markings in the core code turned up
these functions:
brin_summarize_new_values
pg_stat_reset_single_table_counters
pg_stat_reset_single_function_counters
pg_create_logical_replication_slot
pg_create_physical_replication_slot
pg_drop_replication_slot
The first three of these take OID, so a null argument will normally look
like a zero to them, resulting in "ERROR: could not open relation with OID
0" for brin_summarize_new_values, and no action for the pg_stat_reset_XXX
functions. The other three will dump core on a null argument, though this
is mitigated by the fact that they won't do so until after checking that
the caller is superuser or has rolreplication privilege.
In addition, the pg_logical_slot_get/peek[_binary]_changes family was
intentionally marked nonstrict, but failed to make nullness checks on all
the arguments; so again a null-pointer-dereference crash is possible but
only for superusers and rolreplication users.
Add the missing ARGISNULL checks to the latter functions, and mark the
former functions as strict in pg_proc. Make that change in the back
branches too, even though we can't force initdb there, just so that
installations initdb'd in future won't have the issue. Since none of these
bugs rise to the level of security issues (and indeed the pg_stat_reset_XXX
functions hardly misbehave at all), it seems sufficient to do this.
In addition, fix some order-of-operations oddities in the slot_get_changes
family, mostly cosmetic, but not the part that moves the function's last
few operations into the PG_TRY block. As it stood, there was significant
risk for an error to exit without clearing historical information from
the system caches.
The slot_get_changes bugs go back to 9.4 where that code was introduced.
Back-patch appropriate subsets of the pg_proc changes into all active
branches, as well.
Replay of XLOG_BTREE_VACUUM during Hot Standby was previously thought to require
complex interlocking that matched the requirements on the master. This required
an O(N) operation that became a significant problem with large indexes, causing
replication delays of seconds or in some cases minutes while the
XLOG_BTREE_VACUUM was replayed.
This commit skips the “pin scan” that was previously required, by observing in
detail when and how it is safe to do so, with full documentation. The pin scan
is skipped only in replay; the VACUUM code path on master is not touched here.
The current commit still performs the pin scan for toast indexes, though this
can also be avoided if we recheck scans on toast indexes. Later patch will
address this.
No tests included. Manual tests using an additional patch to view WAL records
and their timing have shown the change in WAL records and their handling has
successfully reduced replication delay.
This new view provides insight into the state of a running WAL receiver
in a HOT standby node.
The information returned includes the PID of the WAL receiver process,
its status (stopped, starting, streaming, etc), start LSN and TLI, last
received LSN and TLI, timestamp of last message send and receipt, latest
end-of-WAL LSN and time, and the name of the slot (if any).
Access to the detailed data is only granted to superusers; others only
get the PID.
Author: Michael Paquier
Reviewer: Haribabu Kommi
pg_ctl is using isatty() to verify whether the process is running in a
terminal, and if not it sends its output to Windows' Event Log ... which
does the wrong thing when the output has been redirected to a pipe, as
reported in bug #13592.
To fix, make pg_ctl use the code we already have to detect service-ness:
in the master branch, move src/backend/port/win32/security.c to src/port
(with suitable tweaks so that it runs properly in backend and frontend
environments); pg_ctl already has access to pgport so it Just Works. In
older branches, that's likely to cause trouble, so instead duplicate the
required code in pg_ctl.c.
Author: Michael Paquier
Bug report and diagnosis: Egon Kocjan
Backpatch: all supported branches
Using cstring as the input type was a poor decision, because that's not
really a full-fledged type. In particular, it lacks implicit coercions
from text or varchar, meaning that usages like to_regproc('foo'||'bar')
wouldn't work; basically the only case that did work without explicit
casting was a simple literal constant argument.
The lack of field complaints about this suggests that hardly anyone
is using these functions, so hopefully fixing it won't cause much of
a compatibility problem. They've only been there since 9.4, anyway.
Petr Korobeinikov
While the in-core authentication mechanism doesn't need to access
pg_shseclabel at all, it's reasonable to think that an authentication
hook will want to look at the label for the role logging in, or for rows
in other catalogs used during the authentication phase of startup.
Catalog version bumped, because this changes the "is nailed" status for
pg_shseclabel.
Author: Adam Brightwell
Fix an oversight in commit 321eed5f0f7563a0: replacing an operator's
selectivity functions needs to result in a corresponding update in
pg_depend. We have a function that can handle that, but it was not
called by AlterOperator().
To fix this without enlarging pg_operator.h's #include list beyond
what clients can safely include, split off the function definitions
into a new file pg_operator_fn.h, similarly to what we've done for
some other catalog header files. It's not entirely clear whether
any client-side code needs to include pg_operator.h, but it seems
prudent to assume that there is some such code somewhere.
The variables newestCommitTs and oldestCommitTs sound as if they are
timestamps, but in fact they are the transaction Ids that correspond
to the newest and oldest timestamps rather than the actual timestamps.
Rename these variables to reflect that they are actually xids: to wit
newestCommitTsXid and oldestCommitTsXid respectively. Also modify
related code in a similar fashion, particularly the user facing output
emitted by pg_controldata and pg_resetxlog.
Complaint and patch by me, review by Tom Lane and Alvaro Herrera.
Backpatch to 9.5 where these variables were first introduced.
Omitted boundaries represent the upper or lower limit of the corresponding
array subscript. This allows simpler specification of many common
use-cases.
(Revised version of commit 9246af6799)
YUriy Zhuravlev
When use_remote_estimate is enabled, consider adding ORDER BY to the
query we sending to the remote server so that we can use that ordered
data for a merge join. Commit f18c944b61
arranges to push down the query pathkeys, which seems like the case
mostly likely to be a win, but testing shows this can sometimes win,
too.
For a regular table, we know which indexes are present and therefore
test whether the ordering provided by each such index is useful. Here,
we take the opposite approach: guess what orderings would be useful if
they could be generated cheaply, and then ask the remote side what those
will cost.
Ashutosh Bapat, with very substantial cosmetic revisions by me. Also
reviewed by Rushabh Lathia.
Previously, -j caused the entire input file to be read in and executed as
a single command string. That's undesirable, not least because any error
causes the entire file to be regurgitated as the "failing query". Some
experimentation suggests a better rule: end the command string when we see
a semicolon immediately followed by two newlines, ie, an empty line after
a query. This serves nicely to break up the existing examples such as
information_schema.sql and system_views.sql. A limitation is that it's
no longer possible to write such a sequence within a string literal or
multiline comment in a file meant to be read with -j; but there are no
instances of such a problem within the data currently used by initdb.
(If someone does make such a mistake in future, it'll be obvious because
they'll get an unterminated-literal or unterminated-comment syntax error.)
Other than that, there shouldn't be any negative consequences; you're not
forced to end statements that way, it's just a better idea in most cases.
In passing, remove src/include/tcop/tcopdebug.h, which is dead code
because it's not included anywhere, and hasn't been for more than
ten years. One of the debug-support symbols it purported to describe
has been unreferenced for at least the same amount of time, and the
other is removed by this commit on the grounds that it was useless:
forcing -j mode all the time would have broken initdb. The lack of
complaints about that, or about the missing inclusion, shows that
no one has tried to use TCOP_DONTUSENEWLINE in many years.
This is necessary so that REASSIGN OWNED does the right thing with
composite types, to wit, that it also alters ownership of the type's
pg_class entry -- previously, the pg_class entry remained owned by the
original user, which caused later other failures such as the new owner's
inability to use ALTER TYPE to rename an attribute of the affected
composite. Also, if the original owner is later dropped, the pg_class
entry becomes owned by a non-existant user which is bogus.
To fix, create a new routine AlterTypeOwner_oid which knows whether to
pass the request to ATExecChangeOwner or deal with it directly, and use
that in shdepReassignOwner rather than calling AlterTypeOwnerInternal
directly. AlterTypeOwnerInternal is now simpler in that it only
modifies the pg_type entry and recurses to handle a possible array type;
higher-level tasks are handled by either AlterTypeOwner directly or
AlterTypeOwner_oid.
I took the opportunity to add a few more objects to the test rig for
REASSIGN OWNED, so that more cases are exercised. Additional ones could
be added for superuser-only-ownable objects (such as FDWs and event
triggers) but I didn't want to push my luck by adding a new superuser to
the tests on a backpatchable bug fix.
Per bug #13666 reported by Chris Pacejo.
Backpatch to 9.5.
(I would back-patch this all the way back, except that it doesn't apply
cleanly in 9.4 and earlier because 59367fdf9 wasn't backpatched. If we
decide that we need this in earlier branches too, we should backpatch
both.)
It emerges that libreadline doesn't notice terminal window size change
events unless they occur while collecting input. This is easy to stumble
over if you resize the window while using a pager to look at query output,
but it can be demonstrated without any pager involvement. The symptom is
that queries exceeding one line are misdisplayed during subsequent input
cycles, because libreadline has the wrong idea of the screen dimensions.
The safest, simplest way to fix this is to call rl_reset_screen_size()
just before calling readline(). That causes an extra ioctl(TIOCGWINSZ)
for every command; but since it only happens when reading from a tty, the
performance impact should be negligible. A more valid objection is that
this still leaves a tiny window during entry to readline() wherein delivery
of SIGWINCH will be missed; but the practical consequences of that are
probably negligible. In any case, there doesn't seem to be any good way to
avoid the race, since readline exposes no functions that seem safe to call
from a generic signal handler --- rl_reset_screen_size() certainly isn't.
It turns out that we also need an explicit rl_initialize() call, else
rl_reset_screen_size() dumps core when called before the first readline()
call.
rl_reset_screen_size() is not present in old versions of libreadline,
so we need a configure test for that. (rl_initialize() is present at
least back to readline 4.0, so we won't bother with a test for it.)
We would need a configure test anyway since libedit's emulation of
libreadline doesn't currently include such a function. Fortunately,
libedit seems not to have any corresponding bug.
Merlin Moncure, adjusted a bit by me
Move the content lock directly into the BufferDesc, so that locking and
pinning a buffer touches only one cache line rather than two. Adjust
the definition of BufferDesc slightly so that this doesn't make the
BufferDesc any larger than one cache line (at least on platforms where
a spinlock is only 1 or 2 bytes).
We can't fit the I/O locks into the BufferDesc and stay within one
cache line, so move those to a completely separate tranche. This
leaves a relatively limited number of LWLocks in the main tranche, so
increase the padding of those remaining locks to a full cache line,
rather than allowing adjacent locks to share a cache line, hopefully
reducing false sharing.
Performance testing shows that these changes make little difference
on laptop-class machines, but help significantly on larger servers,
especially those with more than 2 sockets.
Andres Freund, originally based on an earlier patch by Simon Riggs.
Review and cosmetic adjustments (including heavy rewriting of the
comments) by me.
It's a bit cumbersome to use LWLockNewTrancheId(), because the returned
value needs to be shared between backends so that each backend can call
LWLockRegisterTranche() with the correct ID. So, for built-in tranches,
use a hard-coded value instead.
This is motivated by an upcoming patch adding further built-in tranches.
Andres Freund and Robert Haas
DROP OWNED BY handled GRANT-based ACLs but was not removing roles from
policies. Fix that by having DROP OWNED BY remove the role specified
from the list of roles the policy (or policies) apply to, or the entire
policy (or policies) if it only applied to the role specified.
As with ACLs, the DROP OWNED BY caller must have permission to modify
the policy or a WARNING is thrown and no change is made to the policy.
I originally modeled this data structure on SpecialJoinInfo, but after
commit acfcd45cac that looks like a pretty poor decision.
All we really need is relid sets identifying laterally-referenced rels;
and most of the time, what we want to know about includes indirect lateral
references, a case the LateralJoinInfo data was unsuited to compute with
any efficiency. The previous commit redefined RelOptInfo.lateral_relids
as the transitive closure of lateral references, so that it easily supports
checking indirect references. For the places where we really do want just
direct references, add a new RelOptInfo field direct_lateral_relids, which
is easily set up as a copy of lateral_relids before we perform the
transitive closure calculation. Then we can just drop lateral_info_list
and LateralJoinInfo and the supporting code. This makes the planner's
handling of lateral references noticeably more efficient, and shorter too.
Such a change can't be back-patched into stable branches for fear of
breaking extensions that might be looking at the planner's data structures;
but it seems not too late to push it into 9.5, so I've done so.
More fuzz testing by Andreas Seltenreich exposed that the planner did not
cope well with chains of lateral references. If relation X references Y
laterally, and Y references Z laterally, then we will have to scan X on the
inside of a nestloop with Z, so for all intents and purposes X is laterally
dependent on Z too. The planner did not understand this and would generate
intermediate joins that could not be used. While that was usually harmless
except for wasting some planning cycles, under the right circumstances it
would lead to "failed to build any N-way joins" or "could not devise a
query plan" planner failures.
To fix that, convert the existing per-relation lateral_relids and
lateral_referencers relid sets into their transitive closures; that is,
they now show all relations on which a rel is directly or indirectly
laterally dependent. This not only fixes the chained-reference problem
but allows some of the relevant tests to be made substantially simpler
and faster, since they can be reduced to simple bitmap manipulations
instead of searches of the LateralJoinInfo list.
Also, when a PlaceHolderVar that is due to be evaluated at a join contains
lateral references, we should treat those references as indirect lateral
dependencies of each of the join's base relations. This prevents us from
trying to join any individual base relations to the lateral reference
source before the join is formed, which again cannot work.
Andreas' testing also exposed another oversight in the "dangerous
PlaceHolderVar" test added in commit 85e5e222b1. Simply rejecting
unsafe join paths in joinpath.c is insufficient, because in some cases
we will end up rejecting *all* possible paths for a particular join, again
leading to "could not devise a query plan" failures. The restriction has
to be known also to join_is_legal and its cohort functions, so that they
will not select a join for which that will happen. I chose to move the
supporting logic into joinrels.c where the latter functions are.
Back-patch to 9.3 where LATERAL support was introduced.
This module needs explicit initialization in order to replay WAL records
in recovery, but we had broken this recently following changes to make
other (stranger) scenarios work correctly. To fix, rework the
initialization sequence so that it always takes place before WAL replay
commences for both master and standby.
I could have gone for a more localized fix that just added a "startup"
call for the master server, but it seemed better to restructure the
existing callers as well so that the whole thing made more sense. As a
drawback, there is more control logic in xlog.c now than previously, but
doing otherwise meant passing down the ControlFile flag, which seemed
uglier as a whole.
This also meant adding a check to not re-execute ActivateCommitTs if it
had already been called.
Reported by Fujii Masao.
Backpatch to 9.5.
At the end of crash recovery, unlogged relations are reset to the empty
state, using their init fork as the template. The init fork is copied to
the main fork without going through shared buffers. Unfortunately WAL
replay so far has not necessarily flushed writes from shared buffers to
disk at that point. In normal crash recovery, and before the
introduction of 'fast promotions' in fd4ced523 / 9.3, the
END_OF_RECOVERY checkpoint flushes the buffers out in time. But with
fast promotions that's not the case anymore.
To fix, force WAL writes targeting the init fork to be flushed
immediately (using the new FlushOneBuffer() function). In 9.5+ that
flush can centrally be triggered from the code dealing with restoring
full page writes (XLogReadBufferForRedoExtended), in earlier releases
that responsibility is in the hands of XLOG_HEAP_NEWPAGE's replay
function.
Backpatch to 9.1, even if this currently is only known to trigger in
9.3+. Flushing earlier is more robust, and it is advantageous to keep
the branches similar.
Typical symptoms of this bug are errors like
'ERROR: index "..." contains unexpected zero page at block 0'
shortly after promoting a node.
Reported-By: Thom Brown
Author: Andres Freund and Michael Paquier
Discussion: 20150326175024.GJ451@alap3.anarazel.de
Backpatch: 9.1-
The original parallel sequential scan commit included only very limited
changes to the EXPLAIN output. Aggregated totals from all workers were
displayed, but there was no way to see what each individual worker did
or to distinguish the effort made by the workers from the effort made by
the leader.
Per a gripe by Thom Brown (and maybe others). Patch by me, reviewed
by Amit Kapila.
The single linked list of memory contexts could result in O(N^2)
performance to free a set of contexts if they were not freed in
reverse order of creation. In many cases the reverse order was
used, but there were some significant exceptions that caused real-
world performance problems. Rather than requiring all callers to
care about the order in which contexts were freed, and hunting down
and changing all existing cases where the wrong order was used, we
add one pointer per memory context so that the implementation
details are not so visible.
Jan Wieck
Commit e7cb7ee145 provided basic
infrastructure for allowing a foreign data wrapper or custom scan
provider to replace a join of one or more tables with a scan.
However, this infrastructure failed to take into account the need
for possible EvalPlanQual rechecks, and ExecScanFetch would fail
an assertion (or just overwrite memory) if such a check was attempted
for a plan containing a pushed-down join. To fix, adjust the EPQ
machinery to skip some processing steps when scanrelid == 0, making
those the responsibility of scan's recheck method, which also has
the responsibility in this case of correctly populating the relevant
slot.
To allow foreign scans to gain control in the right place to make
use of this new facility, add a new, optional RecheckForeignScan
method. Also, allow a foreign scan to have a child plan, which can
be used to correctly populate the slot (or perhaps for something
else, but this is the only use currently envisioned).
KaiGai Kohei, reviewed by Robert Haas, Etsuro Fujita, and Kyotaro
Horiguchi.
While convincing myself that commit 7e19db0c09 would solve both of
the problems recently reported by Andreas Seltenreich, I realized that
add_paths_to_joinrel's handling of LATERAL restrictions could be made
noticeably simpler and faster if we were to retain the minimum possible
parameterization for each joinrel (that is, the set of relids supplying
unsatisfied lateral references in it). We already retain that for
baserels, in RelOptInfo.lateral_relids, so we can use that field for
joinrels too.
I re-pgindent'd the files touched here, which affects some unrelated
comments.
This is, I believe, just a minor optimization not a bug fix, so no
back-patch.
It was possible for the planner to decide to join a LATERAL subquery to
the outer side of an outer join before the outer join itself is completed.
Normally that's fine because of the associativity rules, but it doesn't
work if the subquery contains a lateral reference to the inner side of the
outer join. In such a situation the outer join *must* be done first.
join_is_legal() missed this consideration and would allow the join to be
attempted, but the actual path-building code correctly decided that no
valid join path could be made, sometimes leading to planner errors such as
"failed to build any N-way joins".
Per report from Andreas Seltenreich. Back-patch to 9.3 where LATERAL
support was added.
As pointed out by Fujii Masao, we weren't quite there on a standby
behaving sanely: first because we were failing to acquire the correct
state in the case where no XLOG_PARAMETER_CHANGE message was sent
(because a checkpoint had already happened after the setting was changed
in the master, and then the standby was restarted); and second because
promoting the standby with the feature enabled failed to activate it if
the master had the feature disabled.
This patch fixes both those misbehaviors hopefully without
re-introducing any old problems.
Also change the hint emitted in a standby together with the error
message about the feature being disabled, to make it point out that the
place to chance the setting is the master. Otherwise, if the setting is
already enabled in the standby, it is very confusing to have it say that
the setting must be enabled ...
Authors: Álvaro Herrera, Petr Jelínek.
Backpatch to 9.5.
In commit 8abb3cda0d I attempted to cache
the expression state trees constructed for domain CHECK constraints for
the life of the backend (assuming the domain's constraints don't get
redefined). However, this turns out not to work very well, because
execQual.c will run those state trees with ecxt_per_query_memory pointing
to a query-lifespan context, and in some situations we'll end up with
pointers into that context getting stored into the state trees. This
happens in particular with SQL-language functions, as reported by
Emre Hasegeli, but there are many other cases.
To fix, keep only the expression plan trees for domain CHECK constraints
in the typcache's data structure, and revert to performing ExecInitExpr
(at least) once per query to set up expression state trees in the query's
context.
Eventually it'd be nice to undo this, but that will require some careful
thought about memory management for expression state trees, and it seems
far too late for any such redesign in 9.5. This way is still much more
efficient than what happened before 8abb3cda0.
Previously, we did many conversions for Cyrillic and Central European
single-byte encodings by converting to a related MULE_INTERNAL coding
scheme before converting to the destination. This seems unnecessarily
inefficient. Moreover, if the conversion encounters an untranslatable
character, the error message will confusingly complain about failure
to convert to or from MULE_INTERNAL, rather than the user-visible
encodings. Worse still, this approach results in some completely
unnecessary conversion failures; there are cases where the chosen
MULE subset lacks characters that exist in both of the user-visible
encodings, causing a conversion failure that need not occur.
This patch fixes the first two of those deficiencies by introducing
a new local2local() conversion support subroutine for direct conversion
between any two single-byte character sets, and adding new conversion
tables where needed. However, I generated the new conversion tables by
testing PG 9.5's behavior, so that the actual conversion behavior is
bug-compatible with previous releases; the only user-visible behavior
change is that the error messages for conversion failures are saner.
Changes in the conversion behavior will probably ensue after discussion.
Interestingly, although this approach requires more tables, the .so files
actually end up smaller (at least on my x86_64 machine); the tables are
smaller than the management code needed for double conversion.
Per a complaint from Albe Laurenz.
The POSIX standard for tar headers requires archive member sizes to be
printed in octal with at most 11 digits, limiting the representable file
size to 8GB. However, GNU tar and apparently most other modern tars
support a convention in which oversized values can be stored in base-256,
allowing any practical file to be a tar member. Adopt this convention
to remove two limitations:
* pg_dump with -Ft output format failed if the contents of any one table
exceeded 8GB.
* pg_basebackup failed if the data directory contained any file exceeding
8GB. (This would be a fatal problem for installations configured with a
table segment size of 8GB or more, and it has also been seen to fail when
large core dump files exist in the data directory.)
File sizes under 8GB are still printed in octal, so that no compatibility
issues are created except in cases that would have failed entirely before.
In addition, this patch fixes several bugs in the same area:
* In 9.3 and later, we'd defined tarCreateHeader's file-size argument as
size_t, which meant that on 32-bit machines it would write a corrupt tar
header for file sizes between 4GB and 8GB, even though no error was raised.
This broke both "pg_dump -Ft" and pg_basebackup for such cases.
* pg_restore from a tar archive would fail on tables of size between 4GB
and 8GB, on machines where either "size_t" or "unsigned long" is 32 bits.
This happened even with an archive file not affected by the previous bug.
* pg_basebackup would fail if there were files of size between 4GB and 8GB,
even on 64-bit machines.
* In 9.3 and later, "pg_basebackup -Ft" failed entirely, for any file size,
on 64-bit big-endian machines.
In view of these potential data-loss bugs, back-patch to all supported
branches, even though removal of the documented 8GB limit might otherwise
be considered a new feature rather than a bug fix.
The previous way of reconstructing check constraints was to do a separate
"ALTER TABLE ONLY tab ADD CONSTRAINT" for each table in an inheritance
hierarchy. However, that way has no hope of reconstructing the check
constraints' own inheritance properties correctly, as pointed out in
bug #13779 from Jan Dirk Zijlstra. What we should do instead is to do
a regular "ALTER TABLE", allowing recursion, at the topmost table that
has a particular constraint, and then suppress the work queue entries
for inherited instances of the constraint.
Annoyingly, we'd tried to fix this behavior before, in commit 5ed6546cf,
but we failed to notice that it wasn't reconstructing the pg_constraint
field values correctly.
As long as I'm touching pg_get_constraintdef_worker anyway, tweak it to
always schema-qualify the target table name; this seems like useful backup
to the protections installed by commit 5f173040.
In HEAD/9.5, get rid of get_constraint_relation_oids, which is now unused.
(I could alternatively have modified it to also return conislocal, but that
seemed like a pretty single-purpose API, so let's not pretend it has some
other use.) It's unused in the back branches as well, but I left it in
place just in case some third-party code has decided to use it.
In HEAD/9.5, also rename pg_get_constraintdef_string to
pg_get_constraintdef_command, as the previous name did nothing to explain
what that entry point did differently from others (and its comment was
equally useless). Again, that change doesn't seem like material for
back-patching.
I did a bit of re-pgindenting in tablecmds.c in HEAD/9.5, as well.
Otherwise, back-patch to all supported branches.
This was already true for CREATE EXTENSION, but historically has not
been true for other object types. Therefore, this is a backward
incompatibility. Per discussion on pgsql-hackers, everyone seems to
agree that the new behavior is better.
Marti Raudsepp, reviewed by Haribabu Kommi and myself
Prior to commit 0709b7ee72, access to
variables within a spinlock-protected critical section had to be done
through a volatile pointer, but that should no longer be necessary.
Review by Andres Freund
This makes it significantly easier to identify these lwlocks in
LWLOCK_STATS or Trace_lwlocks output. It's also arguably better
from a modularity standpoint, since lwlock.c no longer needs to
know anything about the LWLock needs of the higher-level SLRU
facility.
Ildus Kurbangaliev, reviewd by Álvaro Herrera and by me.
Commit a0d9f6e434 added this support for
all other plan node types; this fills in the gap.
Since TextOutCustomScan complicates this and is pretty well useless,
remove it.
KaiGai Kohei, with some modifications by me.
Add a new flag, consider_parallel, to each RelOptInfo, indicating
whether a plan for that relation could conceivably be run inside of
a parallel worker. Right now, we're pretty conservative: for example,
it might be possible to defer applying a parallel-restricted qual
in a worker, and later do it in the leader, but right now we just
don't try to parallelize access to that relation. That's probably
the right decision in most cases, anyway.
Using the new flag, generate parallel sequential scan plans for plain
baserels, meaning that we now have parallel sequential scan in
PostgreSQL. The logic here is pretty unsophisticated right now: the
costing model probably isn't right in detail, and we can't push joins
beneath Gather nodes, so the number of plans that can actually benefit
from this is pretty limited right now. Lots more work is needed.
Nevertheless, it seems time to enable this functionality so that all
this code can actually be tested easily by users and developers.
Note that, if you wish to test this functionality, it will be
necessary to set max_parallel_degree to a value greater than the
default of 0. Once a few more loose ends have been tidied up here, we
might want to consider changing the default value of this GUC, but
I'm leaving it alone for now.
Along the way, fix a bug in cost_gather: the previous coding thought
that a Gather node's transfer overhead should be costed on the basis of
the relation size rather than the number of tuples that actually need
to be passed off to the leader.
Patch by me, reviewed in earlier versions by Amit Kapila.
In addition, this path fills in a number of missing bits and pieces in
the parallel infrastructure. Paths and plans now have a parallel_aware
flag indicating whether whatever parallel-aware logic they have should
be engaged. It is believed that we will need this flag for a number of
path/plan types, not just sequential scans, which is why the flag is
generic rather than part of the SeqScan structures specifically.
Also, execParallel.c now gives parallel nodes a chance to initialize
their PlanState nodes from the DSM during parallel worker startup.
Amit Kapila, with a fair amount of adjustment by me. Review of previous
patch versions by Haribabu Kommi and others.
Commit 4a4e6893aa, which introduced this
mechanism, failed to account for the fact that the RECORD pseudo-type
uses transient typmods that are only meaningful within a single
backend. Transferring such tuples without modification between two
cooperating backends does not work. This commit installs a system
for passing the tuple descriptors over the same shm_mq being used to
send the tuples themselves. The two sides might not assign the same
transient typmod to any given tuple descriptor, so we must also
substitute the appropriate receiver-side typmod for the one used by
the sender. That adds some CPU overhead, but still seems better than
being unable to pass records between cooperating parallel processes.
Along the way, move the logic for handling multiple tuple queues from
tqueue.c to nodeGather.c; tqueue.c now provides a TupleQueueReader,
which reads from a single queue, rather than a TupleQueueFunnel, which
potentially reads from multiple queues. This change was suggested
previously as a way to make sure that nodeGather.c rather than tqueue.c
had policy control over the order in which to read from queues, but
it wasn't clear to me until now how good an idea it was. typmod
mapping needs to be performed separately for each queue, and it is
much simpler if the tqueue.c code handles that and leaves multiplexing
multiple queues to higher layers of the stack.
This introduces a simple encoding scheme to produce abbreviated keys:
pack as many bytes of each UUID as will fit into a Datum. On
little-endian machines, a byteswap is also performed; the abbreviated
comparator can therefore just consist of a simple 3-way unsigned integer
comparison.
The purpose of this change is to speed up sorting data on a column
of type UUID.
Peter Geoghegan
Up until now, the total amount of data that could be passed to a
background worker at startup was one datum, which can be a small as
4 bytes on some systems. That's enough to pass a dsm_handle or an
array index, but not much else. Add a bgw_extra flag to the
BackgroundWorker struct, allowing up to 128 bytes to be passed to
a new worker on any platform.
Use this to fix a problem I recently discovered with the parallel
context machinery added in 9.5: the master assigns each worker an
array index, and each worker subsequently assigns itself an array
index, and there's nothing to guarantee that the two sets of indexes
match, leading to chaos.
Normally, I would not back-patch the change to add bgw_extra, since it
is basically a feature addition. However, since 9.5 is still in beta
and there seems to be no other sensible way to repair the broken
parallel context machinery, back-patch to 9.5. Existing background
worker code can ignore the bgw_extra field without a problem, but
might need to be recompiled since the structure size has changed.
Report and patch by me. Review by Amit Kapila.
The user can whitelist specified extension(s) in the foreign server's
options, whereupon we will treat immutable functions and operators of those
extensions as candidates to be sent for remote execution.
Whitelisting an extension in this way basically promises that the extension
exists on the remote server and behaves compatibly with the local instance.
We have no way to prove that formally, so we have to rely on the user to
get it right. But this seems like something that people can usually get
right in practice.
We might in future allow functions and operators to be whitelisted
individually, but extension granularity is a very convenient special case,
so it got done first.
The patch as-committed lacks any regression tests, which is unfortunate,
but introducing dependencies on other extensions for testing purposes
would break "make installcheck" scenarios, which is worse. I have some
ideas about klugy ways around that, but it seems like material for a
separate patch. For the moment, leave the problem open.
Paul Ramsey, hacked up a bit more by me
Commit d1b7c1ffe7 introduced a mechanism
for serializing a ParamListInfo structure to be passed to a parallel
worker. However, this mechanism failed to handle external expanded
values, as pointed out by Noah Misch. Repair.
Moreover, plpgsql_param_fetch requires adjustment because the
serialization mechanism needs it to skip evaluating unused parameters
just as we would do when it is called from copyParamList, but params
== estate->paramLI in that case. To fix, make the bms_is_member test
in that function unconditional.
Finally, have setup_param_list set a new ParamListInfo field,
paramMask, to the parameters actually used in the expression, so that
we don't try to fetch those that are not needed when serializing a
parameter list. This isn't necessary for correctness, but it makes
the performance of the parallel executor code comparable to what we
do for cases involving cursors.
Design suggestions and extensive review by Noah Misch. Patch by me.
A lookbehind constraint is like a lookahead constraint in that it consumes
no text; but it checks for existence (or nonexistence) of a match *ending*
at the current point in the string, rather than one *starting* at the
current point. This is a long-requested feature since it exists in many
other regex libraries, but Henry Spencer had never got around to
implementing it in the code we use.
Just making it work is actually pretty trivial; but naive copying of the
logic for lookahead constraints leads to code that often spends O(N^2) time
to scan an N-character string, because we have to run the match engine
from string start to the current probe point each time the constraint is
checked. In typical use-cases a lookbehind constraint will be written at
the start of the regex and hence will need to be checked at every character
--- so O(N^2) work overall. To fix that, I introduced a third copy of the
core DFA matching loop, paralleling the existing longest() and shortest()
loops. This version, matchuntil(), can suspend and resume matching given
a couple of pointers' worth of storage space. So we need only run it
across the string once, stopping at each interesting probe point and then
resuming to advance to the next one.
I also put in an optimization that simplifies one-character lookahead and
lookbehind constraints, such as "(?=x)" or "(?<!\w)", into AHEAD and BEHIND
constraints, which already existed in the engine. This avoids the overhead
of the LACON machinery entirely for these rather common cases.
The net result is that lookbehind constraints run a factor of three or so
slower than Perl's for multi-character constraints, but faster than Perl's
for one-character constraints ... and they work fine for variable-length
constraints, which Perl gives up on entirely. So that's not bad from a
competitive perspective, and there's room for further optimization if
anyone cares. (In reality, raw scan rate across a large input string is
probably not that big a deal for Postgres usage anyway; so I'm happy if
it's linear.)
Commit b0b0d84b3d purported to make it
possible to relaunch workers using the same parallel context, but it had
an unpleasant race condition: we might reinitialize after the workers
have sent their last control message but before they have dettached the
DSM, leaving to crashes. Repair by introducing a new ParallelContext
operation, ReinitializeParallelDSM.
Adjust execParallel.c to use this new support, so that we can rescan a
Gather node by relaunching workers but without needing to recreate the
DSM.
Amit Kapila, with some adjustments by me. Extracted from latest parallel
sequential scan patch.
The original Gather code failed to mark a Gather node as not able to
do projection, but it couldn't, even though it did call initialize its
projection info via ExecAssignProjectionInfo. There doesn't seem to
be any good reason for this node not to have projection capability,
so clean things up so that it does. Without this, plans using Gather
nodes might need to carry extra Result nodes to do projection.
Further tweak commit_ts.c so that on a standby the state is completely
consistent with what that in the master, rather than behaving
differently in the cases that the settings differ. Now in standby and
master the module should always be active or inactive in lockstep.
Author: Petr Jelínek, with some further tweaks by Álvaro Herrera.
Backpatch to 9.5, where commit timestamps were introduced.
Discussion: http://www.postgresql.org/message-id/5622BF9D.2010409@2ndquadrant.com
Commit bda76c1c8c caused both plus and
minus infinity to be rendered as "infinity", which is not only wrong
but inconsistent with the pre-9.4 behavior of to_json(). Fix that by
duplicating the coding in date_out/timestamp_out/timestamptz_out more
closely. Per bug #13687 from Stepan Perlov. Back-patch to 9.4, like
the previous commit.
In passing, also re-pgindent json.c, since it had gotten a bit messed up by
recent patches (and I was already annoyed by indentation-related problems
in back-patching this fix ...)
Using this API, one backend can set up a ParallelHeapScanDesc to
which multiple backends can then attach. Each tuple in the relation
will be returned to exactly one of the scanning backends. Only
forward scans are supported, and rescans must be carefully
coordinated.
This is not exposed to the planner or executor yet.
The original version of this code was written by me. Amit Kapila
reviewed it, tested it, and improved it, including adding support for
synchronized scans, per review comments from Jeff Davis. Extensive
testing of this and related patches was performed by Haribabu Kommi.
Final cleanup of this patch by me.
This may allow some callers to avoid the overhead involved in tearing
down a parallel context and then setting up a new one, which means
releasing the DSM and then allocating and populating a new one. I
suspect we'll want to revise the Gather node to make use of this new
capability, but even if not it may be useful elsewhere and requires
very little additional code.
This code previously counted the number of NFA states it created, and
complained if a limit was exceeded, so as to prevent bizarre regex patterns
from consuming unreasonable time or memory. That's fine as far as it went,
but the code paid no attention to how many arcs linked those states. Since
regexes can be contrived that have O(N) states but will need O(N^2) arcs
after fixempties() processing, it was still possible to blow out memory,
and take a long time doing it too. To fix, modify the bookkeeping to count
space used by both states and arcs.
I did not bother with including the "color map" in the accounting; it
can only grow to a few megabytes, which is not a lot in comparison to
what we're allowing for states+arcs (about 150MB on 64-bit machines
or half that on 32-bit machines).
Looking at some of the larger real-world regexes captured in the Tcl
regression test suite suggests that the most that is likely to be needed
for regexes found in the wild is under 10MB, so I believe that the current
limit has enough headroom to make it okay to keep it as a hard-wired limit.
In connection with this, redefine REG_ETOOBIG as meaning "regular
expression is too complex"; the previous wording of "nfa has too many
states" was already somewhat inapropos because of the error code's use
for stack depth overrun, and it was not very user-friendly either.
Back-patch to all supported branches.
Change the singly-linked in-arc and out-arc lists to be doubly-linked,
so that arc deletion is constant time rather than having worst-case time
proportional to the number of other arcs on the connected states.
Modify the bulk arc transfer operations copyins(), copyouts(), moveins(),
moveouts() so that they use a sort-and-merge algorithm whenever there's
more than a small number of arcs to be copied or moved. The previous
method is O(N^2) in the number of arcs involved, because it performs
duplicate checking independently for each copied arc. The new method may
change the ordering of existing arcs for the destination state, but nothing
really cares about that.
Provide another bulk arc copying method mergeins(), which is unused as
of this commit but is needed for the next one. It basically is like
copyins(), but the source arcs might not all come from the same state.
Replace the O(N^2) bubble-sort algorithm used in carcsort() with a qsort()
call.
These changes greatly improve the performance of regex compilation for
large or complex regexes, at the cost of extra space for arc storage during
compilation. The original tradeoff was probably fine when it was made, but
now we care more about speed and less about memory consumption.
Back-patch to all supported branches.
In the previous coding, before returning from ExecutorRun, we'd shut
down all parallel workers. This was dead wrong if ExecutorRun was
called with a non-zero tuple count; it had the effect of truncating
the query output. To fix, give ExecutePlan control over whether to
enter parallel mode, and have it refuse to do so if the tuple count
is non-zero. Rewrite the Gather logic so that it can cope with being
called outside parallel mode.
Commit 7aea8e4f2d is largely to blame
for this problem, though this patch modifies some subsequently-committed
code which relied on the guarantees it purported to make.
Commit 7aea8e4f2d was overoptimistic
about the degree of safety associated with running various functions
in parallel mode. Functions that take a table name or OID as an
argument are at least parallel-restricted, because the table might be
temporary, and we currently don't allow parallel workers to touch
temporary tables. Functions that take a query as an argument are
outright unsafe, because the query could be anything, including a
parallel-unsafe query.
Also, the queue of pending notifications is backend-private, so adding
to it from a worker doesn't behave correctly. We could fix this by
transferring the worker's queue of pending notifications to the master
during worker cleanup, but that seems like more trouble than it's
worth for now. In addition to adjusting the pg_proc.h markings, also
add an explicit check for this in async.c.
check_role() tries to verify that the user has permission to become the
requested role, but this is inappropriate in a parallel worker, which
needs to exactly recreate the master's authorization settings. So skip
the check in that case.
This fixes a bug in commit 924bcf4f16.
Commit 2bd9e412f9 introduced a mechanism
for relaying protocol messages from a background worker to another
backend via a shm_mq. However, there was no provision for shutting
down the communication channel. Therefore, a protocol message sent
late in the shutdown sequence, such as a DEBUG message resulting from
cranking up log_min_messages, could crash the server. To fix, install
an on_dsm_detach callback that disables sending messages to the shm_mq
when the associated DSM is detached.
This fixes a long-standing bug which was discovered while investigating
the interaction between the new join pushdown code and the EvalPlanQual
machinery: if a ForeignScan appears on the inner side of a paramaterized
nestloop, an EPQ recheck would re-return the original tuple even if
it no longer satisfied the pushed-down quals due to changed parameter
values.
This fix adds a new member to ForeignScan and ForeignScanState and a
new argument to make_foreignscan, and requires changes to FDWs which
push down quals to populate that new argument with a list of quals they
have chosen to push down. Therefore, I'm only back-patching to 9.5,
even though the bug is not new in 9.5.
Etsuro Fujita, reviewed by me and by Kyotaro Horiguchi.
Postmaster child processes that aren't supposed to be attached to shared
memory were not bothering to close the shared memory mapping handle they
inherit from the postmaster process. That's mostly harmless, since the
handle vanishes anyway when the child process exits -- but the syslogger
process, if used, doesn't get killed and restarted during recovery from a
backend crash. That meant that Windows doesn't see the shared memory
mapping as becoming free, so it doesn't delete it and the postmaster is
unable to create a new one, resulting in failure to recover from crashes
whenever logging_collector is turned on.
Per report from Dmitry Vasilyev. It's a bit astonishing that we'd not
figured this out long ago, since it's been broken from the very beginnings
of out native Windows support; probably some previously-unexplained trouble
reports trace to this.
A secondary problem is that on Cygwin (perhaps only in older versions?),
exec() may not detach from the shared memory segment after all, in which
case these child processes did remain attached to shared memory, posing
the risk of an unexpected shared memory clobber if they went off the rails
somehow. That may be a long-gone bug, but we can deal with it now if it's
still live, by detaching within the infrastructure introduced here to deal
with closing the handle.
Back-patch to all supported branches.
Tom Lane and Amit Kapila
If we do some byte-swapping while abbreviating, we can do comparisons
using integer arithmetic rather than memcmp.
Peter Geoghegan, reviewed and slightly revised by me.
This flag has proven to be a recipe for bugs, and it doesn't seem like
it can really buy anything in terms of performance. So let's just
*always* set the process latch when we receive SIGUSR1 instead of
trying to do it only when needed.
Per my recent proposal on pgsql-hackers.
This is like BSWAP32, but for 64-bit values. Since we've got two of
them now and they have use cases (like sortsupport) beyond CRCs, move
the definitions to their own header file.
Peter Geoghegan
The postmaster now checks every minute or so (worst case, at most two
minutes) that postmaster.pid is still there and still contains its own PID.
If not, it performs an immediate shutdown, as though it had received
SIGQUIT.
The original goal behind this change was to ensure that failed buildfarm
runs would get fully cleaned up, even if the test scripts had left a
postmaster running, which is not an infrequent occurrence. When the
buildfarm script removes a test postmaster's $PGDATA directory, its next
check on postmaster.pid will fail and cause it to exit. Previously, manual
intervention was often needed to get rid of such orphaned postmasters,
since they'd block new test postmasters from obtaining the expected socket
address.
However, by checking postmaster.pid and not something else, we can provide
additional robustness: manual removal of postmaster.pid is a frequent DBA
mistake, and now we can at least limit the damage that will ensue if a new
postmaster is started while the old one is still alive.
Back-patch to all supported branches, since we won't get the desired
improvement in buildfarm reliability otherwise.
The WithCheckOptions list in Query are only populated during rewrite and
do not need to be written out or read in as part of a Query structure.
Further, move WithCheckOptions to the bottom and add comments to clarify
that it is only populated during rewrite.
Back-patch to 9.5 with a catversion bump, as we are still in alpha.
To allow users to force RLS to always be applied, even for table owners,
add ALTER TABLE .. FORCE ROW LEVEL SECURITY.
row_security=off overrides FORCE ROW LEVEL SECURITY, to ensure pg_dump
output is complete (by default).
Also add SECURITY_NOFORCE_RLS context to avoid data corruption when
ALTER TABLE .. FORCE ROW SECURITY is being used. The
SECURITY_NOFORCE_RLS security context is used only during referential
integrity checks and is only considered in check_enable_rls() after we
have already checked that the current user is the owner of the relation
(which should always be the case during referential integrity checks).
Back-patch to 9.5 where RLS was added.
Limit the size of the hashtable pointer array to not more than
MaxAllocSize, per reports from Kouhei Kaigai and others of "invalid memory
alloc request size" failures. There was discussion of allowing the array
to get larger than that by using the "huge" palloc API, but so far no proof
that that is actually a good idea, and at this point in the 9.5 cycle major
changes from old behavior don't seem like the way to go.
Fix a rather serious secondary bug in the new code, which was that it
didn't ensure nbuckets remained a power of 2 when recomputing it for the
multiple-batch case.
Clean up sloppy division of labor between ExecHashIncreaseNumBuckets and
its sole call site.
Specifically, make its effect independent from the row_security GUC, and
make it affect permission checks pertinent to views the BYPASSRLS role
owns. The row_security GUC thereby ceases to change successful-query
behavior; it can only make a query fail with an error. Back-patch to
9.5, where BYPASSRLS was introduced.
Some of the functions in regex compilation and execution recurse, and
therefore could in principle be driven to stack overflow. The Tcl crew
has seen this happen in practice in duptraverse(), though their fix was
to put in a hard-wired limit on the number of recursive levels, which is
not too appetizing --- fortunately, we have enough infrastructure to check
the actually available stack. Greg Stark has also seen it in other places
while fuzz testing on a machine with limited stack space. Let's put guards
in to prevent crashes in all these places.
Since the regex code would leak memory if we simply threw elog(ERROR),
we have to introduce an API that checks for stack depth without throwing
such an error. Fortunately that's not difficult.
Module initialization was still not completely correct after commit
6b61955135, per crash report from Takashi Ohnishi. To fix, instead of
trying to monkey around with the value of the GUC setting directly, add
a separate boolean flag that enables the feature on a standby, but only
for the startup (recovery) process, when it sees that its master server
has the feature enabled.
Discussion: http://www.postgresql.org/message-id/ca44c6c7f9314868bdc521aea4f77cbf@MP-MSGSS-MBX004.msg.nttdata.co.jp
Also change the deactivation routine to delete all segment files rather
than leaving the last one around. (This doesn't need separate
WAL-logging, because on recovery we execute the same deactivation
routine anyway.)
In passing, clean up the code structure somewhat, particularly so that
xlog.c doesn't know so much about when to activate/deactivate the
feature.
Thanks to Fujii Masao for testing and Petr Jelínek for off-list discussion.
Back-patch to 9.5, where commit_ts was introduced.
A Gather executor node runs any number of copies of a plan in an equal
number of workers and merges all of the results into a single tuple
stream. It can also run the plan itself, if the workers are
unavailable or haven't started up yet. It is intended to work with
the Partial Seq Scan node which will be added in future commits.
It could also be used to implement parallel query of a different sort
by itself, without help from Partial Seq Scan, if the single_copy mode
is used. In that mode, a worker executes the plan, and the parallel
leader does not, merely collecting the worker's results. So, a Gather
node could be inserted into a plan to split the execution of that plan
across two processes. Nested Gather nodes aren't currently supported,
but we might want to add support for that in the future.
There's nothing in the planner to actually generate Gather nodes yet,
so it's not quite time to break out the champagne. But we're getting
close.
Amit Kapila. Some designs suggestions were provided by me, and I also
reviewed the patch. Single-copy mode, documentation, and other minor
changes also by me.
There are three main changes here:
1. No longer cause a start failure in a standby if the feature is
disabled in postgresql.conf but enabled in the master. This reverts one
part of commit 4f3924d9cd43; what we keep is the ability of the standby
to activate/deactivate the module (which includes creating and removing
segments as appropriate) during replay of such actions in the master.
2. Replay WAL records affecting commitTS even if the feature is
disabled. This means the standby will always have the same state as the
master after replay.
3. Have COMMIT PREPARE record the transaction commit time as well. We
were previously only applying it in the normal transaction commit path.
Author: Petr Jelínek
Discussion: http://www.postgresql.org/message-id/CAHGQGwHereDzzzmfxEBYcVQu3oZv6vZcgu1TPeERWbDc+gQ06g@mail.gmail.com
Discussion: http://www.postgresql.org/message-id/CAHGQGwFuzfO4JscM9LCAmCDCxp_MfLvN4QdB+xWsS-FijbjTYQ@mail.gmail.com
Additionally, I cleaned up nearby code related to replication origins,
which I found a bit hard to follow, and fixed a couple of typos.
Backpatch to 9.5, where this code was introduced.
Per bug reports from Fujii Masao and subsequent discussion.
This code provides infrastructure for a parallel leader to start up
parallel workers to execute subtrees of the plan tree being executed
in the master. User-supplied parameters from ParamListInfo are passed
down, but PARAM_EXEC parameters are not. Various other constructs,
such as initplans, subplans, and CTEs, are also not currently shared.
Nevertheless, there's enough here to support a basic implementation of
parallel query, and we can lift some of the current restrictions as
needed.
Amit Kapila and Robert Haas
In 9.5 and master there is no need to support legacy truncation. This is
just committed separately to make it easier to backpatch the WAL logged
multixact truncation to 9.3 and 9.4 if we later decide to do so.
I bumped master's magic from 0xD086 to 0xD088 and 9.5's from 0xD085 to
0xD087 to avoid 9.5 reusing a value that has been in use on master while
keeping the numbers increasing between major versions.
Discussion: 20150621192409.GA4797@alap3.anarazel.de
Backpatch: 9.5
The fact that multixact truncations are not WAL logged has caused a fair
share of problems. Amongst others it requires to do computations during
recovery while the database is not in a consistent state, delaying
truncations till checkpoints, and handling members being truncated, but
offset not.
We tried to put bandaids on lots of these issues over the last years,
but it seems time to change course. Thus this patch introduces WAL
logging for multixact truncations.
This allows:
1) to perform the truncation directly during VACUUM, instead of delaying it
to the checkpoint.
2) to avoid looking at the offsets SLRU for truncation during recovery,
we can just use the master's values.
3) simplify a fair amount of logic to keep in memory limits straight,
this has gotten much easier
During the course of fixing this a bunch of additional bugs had to be
fixed:
1) Data was not purged from memory the member's SLRU before deleting
segments. This happened to be hard or impossible to hit due to the
interlock between checkpoints and truncation.
2) find_multixact_start() relied on SimpleLruDoesPhysicalPageExist - but
that doesn't work for offsets that haven't yet been flushed to
disk. Add code to flush the SLRUs to fix. Not pretty, but it feels
slightly safer to only make decisions based on actual on-disk state.
3) find_multixact_start() could be called concurrently with a truncation
and thus fail. Via SetOffsetVacuumLimit() that could lead to a round
of emergency vacuuming. The problem remains in
pg_get_multixact_members(), but that's quite harmless.
For now this is going to only get applied to 9.5+, leaving the issues in
the older branches in place. It is quite possible that we need to
backpatch at a later point though.
For the case this gets backpatched we need to handle that an updated
standby may be replaying WAL from a not-yet upgraded primary. We have to
recognize that situation and use "old style" truncation (i.e. looking at
the SLRUs) during WAL replay. In contrast to before, this now happens in
the startup process, when replaying a checkpoint record, instead of the
checkpointer. Doing truncation in the restartpoint is incorrect, they
can happen much later than the original checkpoint, thereby leading to
wraparound. To avoid "multixact_redo: unknown op code 48" errors
standbys would have to be upgraded before primaries.
A later patch will bump the WAL page magic, and remove the legacy
truncation codepaths. Legacy truncation support is just included to make
a possible future backpatch easier.
Discussion: 20150621192409.GA4797@alap3.anarazel.de
Reviewed-By: Robert Haas, Alvaro Herrera, Thomas Munro
Backpatch: 9.5 for now
Previously, a function call appearing at the top level of WHERE had a
hard-wired selectivity estimate of 0.3333333, a kludge conveniently dated
in the source code itself to July 1992. The expectation at the time was
that somebody would soon implement estimator support functions analogous
to those for operators; but no such code has appeared, nor does it seem
likely to in the near future. We do have an alternative solution though,
at least for immutable functions on single relations: creating an
expression index on the function call will allow ANALYZE to gather stats
about the function's selectivity. But the code in clause_selectivity()
failed to make use of such data even if it exists.
Refactor so that that will happen. I chose to make it try this technique
for any clause type for which clause_selectivity() doesn't have a special
case, not just functions. To avoid adding unnecessary overhead in the
common case where we don't learn anything new, make selfuncs.c provide an
API that hooks directly to examine_variable() and then var_eq_const(),
rather than the previous coding which laboriously constructed an OpExpr
only so that it could be expensively deconstructed again.
I preserved the behavior that the default estimate for a function call
is 0.3333333. (For any other expression node type, it's 0.5, as before.)
I had originally thought to make the default be 0.5 across the board, but
changing a default estimate that's survived for twenty-three years seems
like something not to do without a lot more testing than I care to put
into it right now.
Per a complaint from Jehan-Guillaume de Rorthais. Back-patch into 9.5,
but not further, at least for the moment.
Commit e956808328 introduces adding pages
to FSM for ordinary insert, but autoanalyze was able just cleanup
pending list without adding to FSM.
Also fix double call of IndexFreeSpaceMapVacuum() during ginvacuumcleanup()
Report from Fujii Masao
Patch by me
Review by Jeff Janes
This commit's parent made superfluous the bit's sole usage. Referential
integrity checks have long run as the subject table's owner, and that
now implies RLS bypass. Safe use of the bit was tricky, requiring
strict control over the SQL expressions evaluating therein. Back-patch
to 9.5, where the bit was introduced.
Based on a patch by Stephen Frost.
Every query of a single ENABLE ROW SECURITY table has two meanings, with
the row_security GUC selecting between them. With row_security=force
available, every function author would have been advised to either set
the GUC locally or test both meanings. Non-compliance would have
threatened reliability and, for SECURITY DEFINER functions, security.
Authors already face an obligation to account for search_path, and we
should not mimic that example. With this change, only BYPASSRLS roles
need exercise the aforementioned care. Back-patch to 9.5, where the
row_security GUC was introduced.
Since this narrows the domain of pg_db_role_setting.setconfig and
pg_proc.proconfig, one might bump catversion. A row_security=force
setting in one of those columns will elicit a clear message, so don't.
The shm_mq mechanism was built to send error (and notice) messages and
tuples between backends. However, shm_mq itself only deals in raw
bytes. Since commit 2bd9e412f9, we have
had infrastructure for one message to redirect protocol messages to a
queue and for another backend to parse them and do useful things with
them. This commit introduces a somewhat analogous facility for tuples
by adding a new type of DestReceiver, DestTupleQueue, which writes
each tuple generated by a query into a shm_mq, and a new
TupleQueueFunnel facility which reads raw tuples out of the queue and
reconstructs the HeapTuple format expected by the executor.
The TupleQueueFunnel abstraction supports reading from multiple tuple
streams at the same time, but only in round-robin fashion. Someone
could imaginably want other policies, but this should be good enough
to meet our short-term needs related to parallel query, and we can
always extend it later.
This also makes one minor addition to the shm_mq API that didn'
seem worth breaking out as a separate patch.
Extracted from Amit Kapila's parallel sequential scan patch. This
code was originally written by me, and then it was revised by Amit,
and then it was revised some more by me.
After an internal failure in shortest() or longest() while pinning down the
exact location of a match, find() forgot to free the DFA structure before
returning. This is pretty unlikely to occur, since we just successfully
ran the "search" variant of the DFA; but it could happen, and it would
result in a session-lifespan memory leak since this code uses malloc()
directly. Problem seems to have been aboriginal in Spencer's library,
so back-patch all the way.
In passing, correct a thinko in a comment I added awhile back about the
meaning of the "ntree" field.
I happened across these issues while comparing our code to Tcl's version
of the library.
ExplainPreScanNode knows how to iterate over a generic tree of plan
states; factor that logic out into a separate walker function so that
other code, such as upcoming patches for parallel query, can also use
it.
Patch by me, reviewed by Tom Lane.
Commit 013ebc0a7b introduces microvacuum for
GiST, deletetion of tuple marked LP_DEAD uses IndexPageMultiDelete while
recovery code uses IndexPageTupleDelete in loop. This causes a difference
in offset numbers of tuples to delete. Patch introduces usage of
IndexPageMultiDelete in GiST except gistplacetopage() where only one tuple is
deleted at once. That also slightly improve performance, because
IndexPageMultiDelete is more effective.
Patch changes WAL format, so bump wal page magic.
Bug report from Jeff Janes
Diagnostic and patch by Anastasia Lubennikova and me
Commit 924bcf4f16 introduced a framework
for parallel computation in PostgreSQL that makes most but not all
built-in functions safe to execute in parallel mode. In order to have
parallel query, we'll need to be able to determine whether that query
contains functions (either built-in or user-defined) that cannot be
safely executed in parallel mode. This requires those functions to be
labeled, so this patch introduces an infrastructure for that. Some
functions currently labeled as safe may need to be revised depending on
how pending issues related to heavyweight locking under paralllelism
are resolved.
Parallel plans can't be used except for the case where the query will
run to completion. If portal execution were suspended, the parallel
mode restrictions would need to remain in effect during that time, but
that might make other queries fail. Therefore, this patch introduces
a framework that enables consideration of parallel plans only when it
is known that the plan will be run to completion. This probably needs
some refinement; for example, at bind time, we do not know whether a
query run via the extended protocol will be execution to completion or
run with a limited fetch count. Having the client indicate its
intentions at bind time would constitute a wire protocol break. Some
contexts in which parallel mode would be safe are not adjusted by this
patch; the default is not to try parallel plans except from call sites
that have been updated to say that such plans are OK.
This commit doesn't introduce any parallel paths or plans; it just
provides a way to determine whether they could potentially be used.
I'm committing it on the theory that the remaining parallel sequential
scan patches will also get committed to this release, hopefully in the
not-too-distant future.
Robert Haas and Amit Kapila. Reviewed (in earlier versions) by Noah
Misch.
Sync our regex code with upstream changes since last time we did this,
which was Tcl 8.5.11 (see commit 08fd6ff37f).
The only functional change here is to disbelieve that an octal escape is
three digits long if it would exceed \377. That's a bug fix, but it's
a minor one and could change the interpretation of working regexes, so
don't back-patch.
In addition to that, s/INFINITY/DUPINF/ to eliminate the risk of collisions
with <math.h>'s macro, and s/LOCAL/NOPROP/ because that also seems like
an unnecessarily collision-prone macro name.
There were some other cosmetic changes in their copy that I did not adopt,
notably a rather half-hearted attempt at renaming some of the C functions
in a more verbose style. (I'm not necessarily against the concept, but
renaming just a few functions in the package is not an improvement.)
This refactors rewrite/rowsecurity.c to simplify the handling of the
default deny case (reducing the number of places where we check for and
add the default deny policy from three to one) by splitting up the
retrival of the policies from the application of them.
This also allowed us to do away with the policy_id field. A policy_name
field was added for WithCheckOption policies and is used in error
reporting, when available.
Patch by Dean Rasheed, with various mostly cosmetic changes by me.
Back-patch to 9.5 where RLS was introduced to avoid unnecessary
differences, since we're still in alpha, per discussion with Robert.
Naming the individual lwlocks seems like something that may be useful
for other types of debugging, monitoring, or instrumentation output,
but this commit just implements it for the specific case of
trace_lwlocks.
Patch by me, reviewed by Amit Kapila and Kyotaro Horiguchi
Mark index tuple as dead if it's pointed by kill_prior_tuple during
ordinary (search) scan and remove it during insert process if there is no
enough space for new tuple to insert. This improves select performance
because index will not return tuple marked as dead and improves insert
performance because it reduces number of page split.
Anastasia Lubennikova <a.lubennikova@postgrespro.ru> with
minor editorialization by me
This commit makes postmaster forcibly remove the files signaling
a standby promotion request. Otherwise, the existence of those files
can trigger a promotion too early, whether a user wants that or not.
This removal of files is usually unnecessary because they can exist
only during a few moments during a standby promotion. However
there is a race condition: if pg_ctl promote is executed and creates
the files during a promotion, the files can stay around even after
the server is brought up to new master. Then, if new standby starts
by using the backup taken from that master, the files can exist
at the server startup and should be removed in order to avoid
an unexpected promotion.
Back-patch to 9.1 where promote signal file was introduced.
Problem reported by Feike Steenbergen.
Original patch by Michael Paquier, modified by me.
Discussion: 20150528100705.4686.91426@wrigleys.postgresql.org
Per discussion, nowadays it is possible to have tablespaces that have
wildly different I/O characteristics from others. Setting different
effective_io_concurrency parameters for those has been measured to
improve performance.
Author: Julien Rouhaud
Reviewed by: Andres Freund
Since 6fcd885 it is possible to immediately reserve WAL when creating a
slot via pg_create_physical_replication_slot(). Extend the replication
protocol to allow that as well.
Although, in contrast to the SQL interface, it is possible to update the
reserved location via the replication interface, it is still useful
being able to reserve upon creation there. Otherwise the logic in
ReplicationSlotReserveWal() has to be repeated in slot employing
clients.
Author: Michael Paquier
Discussion: CAB7nPqT0Wc1W5mdYGeJ_wbutbwNN+3qgrFR64avXaQCiJMGaYA@mail.gmail.com
Formerly, we treated only portals created in the current subtransaction as
having failed during subtransaction abort. However, if the error occurred
while running a portal created in an outer subtransaction (ie, a cursor
declared before the last savepoint), that has to be considered broken too.
To allow reliable detection of which ones those are, add a bookkeeping
field to struct Portal that tracks the innermost subtransaction in which
each portal has actually been executed. (Without this, we'd end up
failing portals containing functions that had called the subtransaction,
thereby breaking plpgsql exception blocks completely.)
In addition, when we fail an outer-subtransaction Portal, transfer its
resources into the subtransaction's resource owner, so that they're
released early in cleanup of the subxact. This fixes a problem reported by
Jim Nasby in which a function executed in an outer-subtransaction cursor
could cause an Assert failure or crash by referencing a relation created
within the inner subtransaction.
The proximate cause of the Assert failure is that AtEOSubXact_RelationCache
assumed it could blow away a relcache entry without first checking that the
entry had zero refcount. That was a bad idea on its own terms, so add such
a check there, and to the similar coding in AtEOXact_RelationCache. This
provides an independent safety measure in case there are still ways to
provoke the situation despite the Portal-level changes.
This has been broken since subtransactions were invented, so back-patch
to all supported branches.
Tom Lane and Michael Paquier
Post-commit review by Andres Freund discovered a couple of concurrency
bugs in the original patch: specifically, if the leader cleared a
follower's XID before it reached PGSemaphoreLock, the semaphore would be
left in the wrong state; and if another process did PGSemaphoreUnlock
for some unrelated reason, we might resume execution before the fact
that our XID was cleared was globally visible.
Also, improve the wording of some comments, rename nextClearXidElem
to firstClearXidElem in PROC_HDR for clarity, and drop some volatile
qualifiers that aren't necessary.
Amit Kapila, reviewed and slightly revised by me.
Currently, in-memory posting list during GIN build process is limited 1GB
because of using repalloc. The patch replaces call of repalloc to repalloc_huge.
It increases limit of posting list from 180 millions
(1GB / sizeof(ItemPointerData)) to 4 billions limited by maxcount/count fields
in GinEntryAccumulator and subsequent calls. Check added.
Also, fix accounting of allocatedMemory during build to prevent integer
overflow with maintenance_work_mem > 4GB.
Robert Abraham <robert.abraham86@googlemail.com> with additions by me
Some googling turned up multiple sources saying that older versions of icc
do not accept gcc-compatible asm blocks on IA64, though asm does work on
x86[_64]. This is apparently fixed as of icc version 12.0 or so, but that
doesn't help us much; if we have to carry the extra implementation anyway,
we may as well just use it for icc rather than add a compiler version test.
Hence, revert commit 2c713d6ea2 (though I
separated the icc code from the gcc code completely, producing what seems
cleaner code). Document the state of affairs more explicitly, both in
s_lock.h and postgres.c, and make some cosmetic adjustments around the
IA64 code in s_lock.h.
The atomics headers were written under the impression that icc doesn't
handle gcc-style asm blocks, but this is demonstrably false on x86_[64],
because s_lock.h has done it that way for more than a decade. (The jury is
still out on whether this also works on ia64, so I'm leaving ia64-related
code alone for the moment.) Treat gcc and icc the same in these headers.
This is less code and it should improve the results for icc, because we
hadn't gotten around to providing icc-specific implementations for most
of the atomics.
Remove configure's checks for HAVE_POSIX_SIGNALS, HAVE_SIGPROCMASK, and
HAVE_SIGSETJMP. These APIs are required by the Single Unix Spec v2
(POSIX 1997), which we generally consider to define our minimum required
set of Unix APIs. Moreover, no buildfarm member has reported not having
them since 2012 or before, which means that even if the code is still live
somewhere, it's untested --- and we've made plenty of signal-handling
changes of late. So just take these APIs as given and save the cycles for
configure probes for them.
However, we can't remove as much C code as I'd hoped, because the Windows
port evidently still uses the non-POSIX code paths for signal masking.
Since we're largely emulating these BSD-style APIs for Windows anyway, it
might be a good thing to switch over to POSIX-like notation and thereby
remove a few more #ifdefs. But I'm not in a position to code or test that.
In the meantime, we can at least make things a bit more transparent by
testing for WIN32 explicitly in these places.
C89 requires <signal.h> to define sig_atomic_t, and there is no evidence
in the buildfarm that any supported platforms don't comply. Remove the
configure test to stop wasting build cycles on a purely historical issue.
(Once upon a time, we cared about supporting C89-compliant compilers on
machines with pre-C89 system headers, but that use-case has been dead for
quite a few years.)
I have some other fixes planned in this area, but let's start with this
to see if the buildfarm produces any surprising results.
On recent AIX it's necessary to configure gcc to use the native assembler
(because the GNU assembler hasn't been updated to handle AIX 6+). This
caused PG builds to fail with assembler syntax errors, because we'd try
to compile s_lock.h's gcc asm fragment for PPC, and that assembly code
relied on GNU-style local labels. We can't substitute normal labels
because it would fail in any file containing more than one inlined use of
tas(). Fortunately, that code is stable enough, and the PPC ISA is simple
enough, that it doesn't seem like too much of a maintenance burden to just
hand-code the branch offsets, removing the need for any labels.
Note that the AIX assembler only accepts "$" for the location counter
pseudo-symbol. The usual GNU convention is "."; but it appears that all
versions of gas for PPC also accept "$", so in theory this patch will not
break any other PPC platforms.
This has been reported by a few people, but Steve Underwood gets the credit
for being the first to pursue the problem far enough to understand why it
was failing. Thanks also to Noah Misch for additional testing.
We had a report from Stefan Kaltenbrunner of a case in which postmaster
log files overran available disk space because multiple backends spewed
enormous context stats dumps upon hitting an out-of-memory condition.
Given the lack of similar reports, this isn't a common problem, but it
still seems worth doing something about. However, we don't want to just
blindly truncate the output, because that might prevent diagnosis of OOM
problems. What seems like a workable compromise is to limit the dump to
100 child contexts per parent, and summarize the space used within any
additional child contexts. That should help because practical cases where
the dump gets long will typically be huge numbers of siblings under the
same parent context; while the additional debugging value from seeing
details about individual siblings beyond 100 will not be large, we hope.
Anyway it doesn't take much code or memory space to do this, so let's try
it like this and see how things go.
Since the summarization mechanism requires passing totals back up anyway,
I took the opportunity to add a "grand total" line to the end of the
printout.
Since the distances used in this algorithm are small integers (not more
than the size of the U set, in fact), there is no good reason to use float
arithmetic for them. Use short ints instead: they're smaller, faster, and
require no special portability assumptions.
Per testing by Greg Stark, which disclosed that the code got into an
infinite loop on VAX for lack of IEEE-style float infinities. We don't
really care all that much whether Postgres can run on a VAX anymore,
but there seems sufficient reason to change this code anyway.
In passing, make a few other small adjustments to make the code match
usual Postgres coding style a bit better.
To avoid confusion, rename CreatePolicyStmt's 'cmd' to 'cmd_name',
parse_policy_command's 'cmd' to 'polcmd', and AlterPolicy's 'cmd_datum'
to 'polcmd_datum', per discussion with Noah and as a follow-up to his
correction of copynodes/equalnodes handling of the CreatePolicyStmt
'cmd' field.
Back-patch to 9.5 where the CreatePolicyStmt was introduced, as we
are still only in alpha.
Reduce lock levels down to ShareUpdateExclusiveLock for all autovacuum-related
relation options when setting them using ALTER TABLE.
Add infrastructure to allow varying lock levels for relation options in later
patches. Setting multiple options together uses the highest lock level required
for any option. Works for both main and toast tables.
Fabrízio Mello, reviewed by Michael Paquier, mild edit and additional regression
tests from myself
These are emitted by the new ax_pthread.m4 script version. They are not
used for anything in PostgreSQL, but let's keep the generated header file
up-to-date.
Andres Freund
In some corner cases, it is possible for the BRIN index relation to be
extended by brin_getinsertbuffer but the new page not be used
immediately for anything by its callers; when this happens, the page is
initialized and the FSM is updated (by brin_getinsertbuffer) with the
info about that page, but these actions are not WAL-logged. A later
index insert/update can use the page, but since the page is already
initialized, the initialization itself is not WAL-logged then either.
Replay of this sequence of events causes recovery to fail altogether.
There is a related corner case within brin_getinsertbuffer itself, in
which we extend the relation to put a new index tuple there, but later
find out that we cannot do so, and do not return the buffer; the page
obtained from extension is not even initialized. The resulting page is
lost forever.
To fix, shuffle the code so that initialization is not the
responsibility of brin_getinsertbuffer anymore, in normal cases;
instead, the initialization is done by its callers (brin_doinsert and
brin_doupdate) once they're certain that the page is going to be used.
When either those functions determine that the new page cannot be used,
before bailing out they initialize the page as an empty regular page,
enter it in FSM and WAL-log all this. This way, the page is usable for
future index insertions, and WAL replay doesn't find trying to insert
tuples in pages whose initialization didn't make it to the WAL. The
same strategy is used in brin_getinsertbuffer when it cannot return the
new page.
Additionally, add a new step to vacuuming so that all pages of the index
are scanned; whenever an uninitialized page is found, it is initialized
as empty and WAL-logged. This closes the hole that the relation is
extended but the system crashes before anything is WAL-logged about it.
We also take this opportunity to update the FSM, in case it has gotten
out of date.
Thanks to Heikki Linnakangas for finding the problem that kicked some
additional analysis of BRIN page assignment code.
Backpatch to 9.5, where BRIN was introduced.
Discussion: https://www.postgresql.org/message-id/20150723204810.GY5596@postgresql.org
Until now we computed these Param ID sets at the end of subquery_planner,
but that approach depends on subquery_planner returning a concrete Plan
tree. We would like to switch over to returning one or more Paths for a
subquery, and in that representation the necessary details aren't fully
fleshed out (not to mention that we don't really want to do this work for
Paths that end up getting discarded). Hence, refactor so that we can
compute the param ID sets at the end of planning, just before
set_plan_references is run.
The main change necessary to make this work is that we need to capture
the set of outer-level Param IDs available to the current query level
before exiting subquery_planner, since the outer levels' plan_params lists
are transient. (That's not going to pose a problem for returning Paths,
since all the work involved in producing that data is part of expression
preprocessing, which will continue to happen before Paths are produced.)
On the plus side, this change gets rid of several existing kluges.
Eventually I'd like to get rid of SS_finalize_plan altogether in favor of
doing this work during set_plan_references, but that will require some
complex rejiggering because SS_finalize_plan needs to visit subplans and
initplans before the main plan. So leave that idea for another day.
When creating a physical slot it's often useful to immediately reserve
the current WAL position instead of only doing after the first feedback
message arrives. That e.g. allows slots to guarantee that all the WAL
for a base backup will be available afterwards.
Logical slots already have to reserve WAL during creation, so generalize
that logic into being usable for both physical and logical slots.
Catversion bump because of the new parameter.
Author: Gurjeet Singh
Reviewed-By: Andres Freund
Discussion: CABwTF4Wh_dBCzTU=49pFXR6coR4NW1ynb+vBqT+Po=7fuq5iCw@mail.gmail.com
There's no reason not to expose both restart_lsn and confirmed_flush
since they have rather distinct meanings. The former is the oldest WAL
still required and valid for both physical and logical slots, whereas
the latter is the location up to which a logical slot's consumer has
confirmed receiving data. Most of the time a slot will require older
WAL (i.e. restart_lsn) than the confirmed
position (i.e. confirmed_flush_lsn).
Author: Marko Tiikkaja, editorialized by me
Discussion: 559D110B.1020109@joh.to
In de6fd1c8 I moved the the work around from 53f73879 into the aix
template. The previous location was removed in the former commit, and I
thought that it would be nice to emit a warning when running configure.
That didn't turn out to work because at the point the template is
included we don't know whether we're compiling a 32/64 bit binary and
it's possible to install compilers for both on a 64 bit kernel/OS.
So go back to a less ambitious approach and define
PG_FORCE_DISABLE_INLINE in port/aix.h, without emitting a warning. We
could try a more fancy approach, but it doesn't seem worth it.
This requires moving the check for PG_FORCE_DISABLE_INLINE in c.h to
after including the system headers included from therein which isn't
perfect, as it seems slightly more robust to include all system headers
in a similar environment. Oh well.
Discussion: 20150807132000.GC13310@awork2.anarazel.de
Some frontend code like e.g. pg_xlogdump or pg_resetxlog, has to use
backend headers. Unfortunately until now that code includes most of the
locking code. It's generally not nice to expose such low level details,
but de6fd1c898 made that a hard problem. We fall back to defining
'inline' away if the compiler doesn't support it - that can cause linker
errors like on buildfarm animal pademelon if a inline function
references backend only code.
To fix that problem separate definitions from lock.h that are required
from frontend code into lockdefs.h and use it in the relevant
places. I've only removed the minimal amount of necessary definitions
for now - it might turn out that we want more for other reasons.
To avoid such details being exposed again put some checks against being
included from frontend code into atomics.h, lock.h, lwlock.h and
s_lock.h. It's otherwise fairly easy to indirectly include these
headers.
Discussion: 20150806070902.GE12214@awork2.anarazel.de
Formerly, this function would always return "true" for an appendrel child
relation, because it would think that the appendrel parent was a potential
join target for the child. In principle that should only lead to some
inefficiency in planning, but fuzz testing by Andreas Seltenreich disclosed
that it could lead to "could not find pathkey item to sort" planner errors
in odd corner cases. Specifically, we would think that all columns of a
child table's multicolumn index were interesting pathkeys, causing us to
generate a MergeAppend path that sorts by all the columns. However, if any
of those columns weren't actually used above the level of the appendrel,
they would not get added to that rel's targetlist, which would result in
being unable to resolve the MergeAppend's sort keys against its targetlist
during createplan.c.
Backpatch to 9.3. In older versions, columns of an appendrel get added
to its targetlist even if they're not mentioned above the scan level,
so that the failure doesn't occur. It might be worth back-patching this
fix to older versions anyway, but I'll refrain for the moment.
When a write transaction commits, it must clear its XID advertised via
the ProcArray, which requires that we hold ProcArrayLock in exclusive
mode in order to prevent concurrent processes running GetSnapshotData
from seeing inconsistent results. When many processes try to commit
at once, ProcArrayLock must change hands repeatedly, with each
concurrent process trying to commit waking up to acquire the lock in
turn. To make things more efficient, when more than one backend is
trying to commit a write transaction at the same time, have just one
of them acquire ProcArrayLock in exclusive mode and clear the XIDs of
all processes in the group. Benchmarking reveals that this is much
more efficient at very high client counts.
Amit Kapila, heavily revised by me, with some review also from Pavan
Deolasee.
pg_resetxlog.h contained two superfluous includes, origin.h superfluously
depended on logical.h, and pg_xlogdump's rmgrdesc.h only indirectly
included origin.h.
Backpatch: 9.5, where replication origins were introduced.
A few of the discrepancies had semantic significance, but I did not
track down the resulting user-visible bugs, if any. Back-patch to 9.5,
where all but one discrepancy appeared. The _equalCreateEventTrigStmt()
situation dates to 9.3 but does not affect semantics.
catversion bump due to readfuncs.c field order changes.
For correctness of summarization results, it is critical that the
snapshot used during the summarization scan is able to see all tuples
that are live to all transactions -- including tuples inserted or
deleted by in-progress transactions. Otherwise, it would be possible
for a transaction to insert a tuple, then idle for a long time while a
concurrent transaction executes summarization of the range: this would
result in the inserted value not being considered in the summary.
Previously we were trying to use a MVCC snapshot in conjunction with
adding a "placeholder" tuple in the index: the snapshot would see all
committed tuples, and the placeholder tuple would catch insertions by
any new inserters. The hole is that prior insertions by transactions
that are still in progress by the time the MVCC snapshot was taken were
ignored.
Kevin Grittner reported this as a bogus error message during vacuum with
default transaction isolation mode set to repeatable read (because the
error report mentioned a function name not being invoked during), but
the problem is larger than that.
To fix, tweak IndexBuildHeapRangeScan to have a new mode that behaves
the way we need using SnapshotAny visibility rules. This change
simplifies the BRIN code a bit, mainly by removing large comments that
were mistaken. Instead, rely on the SnapshotAny semantics to provide
what it needs. (The business about a placeholder tuple needs to remain:
that covers the case that a transaction inserts a a tuple in a page that
summarization already scanned.)
Discussion: https://www.postgresql.org/message-id/20150731175700.GX2441@postgresql.org
In passing, remove a couple of unused declarations from brin.h and
reword a comment to be proper English. This part submitted by Kevin
Grittner.
Backpatch to 9.5, where BRIN was introduced.
So far we have worked around the fact that some very old compilers do
not support 'inline' functions by only using inline functions
conditionally (or not at all). Since such compilers are very rare by
now, we have decided to rely on inline functions from 9.6 onwards.
To avoid breaking these old compilers inline is defined away when not
supported. That'll cause "function x defined but not used" type of
warnings, but since nobody develops on such compilers anymore that's
ok.
This change in policy will allow us to more easily employ inline
functions.
I chose to remove code previously conditional on PG_USE_INLINE as it
seemed confusing to have code dependent on a define that's always
defined.
Blacklisting of compilers, like in c53f73879f, now has to be done
differently. A platform template can define PG_FORCE_DISABLE_INLINE to
force inline to be defined empty.
Discussion: 20150701161447.GB30708@awork2.anarazel.de
I appear to accidentally have switched the comments for
pg_atomic_write_u32 and pg_atomic_read_u32 around. Also fix some minor
typos I found while fixing.
Noticed-By: Amit Kapila
Backpatch: 9.5
The tuplesort/tuplestore memory management logic assumed that the chunk
allocation overhead for its memtuples array could not increase when
increasing the array size. This is and always was true for tuplesort,
but we (I, I think) blindly copied that logic into tuplestore.c without
noticing that the assumption failed to hold for the much smaller array
elements used by tuplestore. Given rather small work_mem, this could
result in an improper complaint about "unexpected out-of-memory situation",
as reported by Brent DeSpain in bug #13530.
The easiest way to fix this is just to increase tuplestore's initial
array size so that the assumption holds. Rather than relying on magic
constants, though, let's export a #define from aset.c that represents
the safe allocation threshold, and make tuplestore's calculation depend
on that.
Do the same in tuplesort.c to keep the logic looking parallel, even though
tuplesort.c isn't actually at risk at present. This will keep us from
breaking it if we ever muck with the allocation parameters in aset.c.
Back-patch to all supported versions. The error message doesn't occur
pre-9.3, not so much because the problem can't happen as because the
pre-9.3 tuplestore code neglected to check for it. (The chance of
trouble is a great deal larger as of 9.3, though, due to changes in the
array-size-increasing strategy.) However, allowing LACKMEM() to become
true unexpectedly could still result in less-than-desirable behavior,
so let's patch it all the way back.
If there are two different aggregates in the query with same inputs, and
the aggregates have the same initial condition and transition function,
only calculate the state value once, and only call the final functions
separately. For example, AVG(x) and SUM(x) aggregates have the same
transition function, which accumulates the sum and number of input tuples.
For a query like "SELECT AVG(x), SUM(x) FROM x", we can therefore
accumulate the state function only once, which gives a nice speedup.
David Rowley, reviewed and edited by me.
Commit c9b0cbe98b accidentally broke the
order of operations during postmaster shutdown: it resulted in removing
the per-socket lockfiles after, not before, postmaster.pid. This creates
a race-condition hazard for a new postmaster that's started immediately
after observing that postmaster.pid has disappeared; if it sees the
socket lockfile still present, it will quite properly refuse to start.
This error appears to be the explanation for at least some of the
intermittent buildfarm failures we've seen in the pg_upgrade test.
Another problem, which has been there all along, is that the postmaster
has never bothered to close() its listen sockets, but has just allowed them
to close at process death. This creates a different race condition for an
incoming postmaster: it might be unable to bind to the desired listen
address because the old postmaster is still incumbent. This might explain
some odd failures we've seen in the past, too. (Note: this is not related
to the fact that individual backends don't close their client communication
sockets. That behavior is intentional and is not changed by this patch.)
Fix by adding an on_proc_exit function that closes the postmaster's ports
explicitly, and (in 9.3 and up) reshuffling the responsibility for where
to unlink the Unix socket files. Lock file unlinking can stay where it
is, but teach it to unlink the lock files in reverse order of creation.
The lwlock scalability work introduced two race conditions into the
lwlock variable support provided for xlog.c. First, and harmlessly on
most platforms, it set/read the variable without the spinlock in some
places. Secondly, due to the removal of the spinlock, it was possible
that a backend missed changes to the variable's state if it changed in
the wrong moment because checking the lock's state, the variable's state
and the queuing are not protected by a single spinlock acquisition
anymore.
To fix first move resetting the variable's from LWLockAcquireWithVar to
WALInsertLockRelease, via a new function LWLockReleaseClearVar. That
prevents issues around waiting for a variable's value to change when a
new locker has acquired the lock, but not yet set the value. Secondly
re-check that the variable hasn't changed after enqueing, that prevents
the issue that the lock has been released and already re-acquired by the
time the woken up backend checks for the lock's state.
Reported-By: Jeff Janes
Analyzed-By: Heikki Linnakangas
Reviewed-By: Heikki Linnakangas
Discussion: 5592DB35.2060401@iki.fi
Backpatch: 9.5, where the lwlock scalability went in
They are marked stable, but since they act on instantaneous state and it
is possible to consult state of transactions as they commit, the results
could change mid-query. They need to be marked volatile, and this
commit does so.
There would normally be a catversion bump here, but this is so much a
niche feature and I don't believe there's real damage from the incorrect
marking, that I refrained.
Backpatch to 9.5, where commit timestamps where introduced.
Per note from Fujii Masao.
Policy USING and WITH CHECK expressions were using EXPR_KIND_WHERE for
parse analysis, which results in inappropriate ERROR messages when
the expression contains unsupported constructs such as aggregates.
Create a new ParseExprKind called EXPR_KIND_POLICY and tailor the
related messages to fit.
Reported by Noah Misch. Reviewed by Dean Rasheed, Alvaro Herrera,
and Robert Haas. Back-patch to 9.5 where RLS was introduced.
When DefineQueryRewrite() is about to convert a table to a view, it checks
the table for features unavailable to views. For example, it rejects tables
having triggers. It omits to reject tables having relrowsecurity or a
pg_policy record. Fix that. To faciliate the repair, invent
relation_has_policies() which indicates the presence of policies on a
relation even when row security is disabled for that relation.
Reported by Noah Misch. Patch by me, review by Stephen Frost. Back-patch
to 9.5 where RLS was introduced.
CreatePolicy() and AlterPolicy() omit to create a pg_shdepend entry for
each role in the TO clause. Fix this by creating a new shared dependency
type called SHARED_DEPENDENCY_POLICY and assigning it to each role.
Reported by Noah Misch. Patch by me, reviewed by Alvaro Herrera.
Back-patch to 9.5 where RLS was introduced.
As pointed out by Tom, since HEAD has progressed beyond 9.5 in terms of
its catalog, we need to be sure catversion of HEAD is advanced beyond
that of 9.5. Corrects my mistake in the pg_stats view commit cfa928ff.
The pg_stats view is supposed to be restricted to only show rows
about tables the user can read. However, it sometimes can leak
information which could not otherwise be seen when row level security
is enabled. Fix that by not showing pg_stats rows to users that would
be subject to RLS on the table the row is related to. This is done
by creating/using the newly introduced SQL visible function,
row_security_active().
Along the way, clean up three call sites of check_enable_rls(). The second
argument of that function should only be specified as other than
InvalidOid when we are checking as a different user than the current one,
as in when querying through a view. These sites were passing GetUserId()
instead of InvalidOid, which can cause the function to return incorrect
results if the current user has the BYPASSRLS privilege and row_security
has been set to OFF.
Additionally fix a bug causing RI Trigger error messages to unintentionally
leak information when RLS is enabled, and other minor cleanup and
improvements. Also add WITH (security_barrier) to the definition of pg_stats.
Bumped CATVERSION due to new SQL functions and pg_stats view definition.
Back-patch to 9.5 where RLS was introduced. Reported by Yaroslav.
Patch by Joe Conway and Dean Rasheed with review and input by
Michael Paquier and Stephen Frost.
While postgres' use of SSL renegotiation is a good idea in theory, it
turned out to not work well in practice. The specification and openssl's
implementation of it have lead to several security issues. Postgres' use
of renegotiation also had its share of bugs.
Additionally OpenSSL has a bunch of bugs around renegotiation, reported
and open for years, that regularly lead to connections breaking with
obscure error messages. We tried increasingly complex workarounds to get
around these bugs, but we didn't find anything complete.
Since these connection breakages often lead to hard to debug problems,
e.g. spuriously failing base backups and significant latency spikes when
synchronous replication is used, we have decided to change the default
setting for ssl renegotiation to 0 (disabled) in the released
backbranches and remove it entirely in 9.5 and master.
Author: Andres Freund
Discussion: 20150624144148.GQ4797@alap3.anarazel.de
Backpatch: 9.5 and master, 9.0-9.4 get a different patch
This code was originally written as part of parallel query effort, but
it seems to have independent value, because if we make one decision
about where to get a PGPROC when we allocate and then put it back on a
different list at backend-exit time, bad things happen. This isn't
just a theoretical risk; we fixed an actual problem of this type in
commit e280c630a8.
On some platforms, notably ARM and PowerPC, 'char' is unsigned by
default. This fixes an assertion failure at WAL replay on such platforms.
Reported by Noah Misch. Backpatch to 9.5, where this was broken.
SP-GiST initialized an all-zeros page at vacuum, but that was not
WAL-logged, which is not safe. You might get a torn page write, when it gets
flushed to disk, and end-up with a half-initialized index page. To fix,
leave it in the all-zeros state, and add it to the FSM. It will be
initialized when reused. Also don't set the page-deleted flag when recycling
an empty page. That was also not WAL-logged, and a torn write of that would
cause the page to have an invalid checksum.
Backpatch to 9.2, where SP-GiST indexes were added.
The original implementation of TABLESAMPLE modeled the tablesample method
API on index access methods, which wasn't a good choice because, without
specialized DDL commands, there's no way to build an extension that can
implement a TSM. (Raw inserts into system catalogs are not an acceptable
thing to do, because we can't undo them during DROP EXTENSION, nor will
pg_upgrade behave sanely.) Instead adopt an API more like procedural
language handlers or foreign data wrappers, wherein the only SQL-level
support object needed is a single handler function identified by having
a special return type. This lets us get rid of the supporting catalog
altogether, so that no custom DDL support is needed for the feature.
Adjust the API so that it can support non-constant tablesample arguments
(the original coding assumed we could evaluate the argument expressions at
ExecInitSampleScan time, which is undesirable even if it weren't outright
unsafe), and discourage sampling methods from looking at invisible tuples.
Make sure that the BERNOULLI and SYSTEM methods are genuinely repeatable
within and across queries, as required by the SQL standard, and deal more
honestly with methods that can't support that requirement.
Make a full code-review pass over the tablesample additions, and fix
assorted bugs, omissions, infelicities, and cosmetic issues (such as
failure to put the added code stanzas in a consistent ordering).
Improve EXPLAIN's output of tablesample plans, too.
Back-patch to 9.5 so that we don't have to support the original API
in production.
Handling of assigned-to expressions with indirection (e.g. set f1[1] =
3) was broken for ON CONFLICT DO UPDATE. The problem was that
ParseState was consulted to determine if an INSERT-appropriate or
UPDATE-appropriate behavior should be used when transforming expressions
with indirections. When the wrong path was taken the old row was
substituted with NULL, leading to wrong results..
To fix remove p_is_update and only use p_is_insert to decide how to
transform the assignment expression, and uset p_is_insert while parsing
the on conflict statement. This isn't particularly pretty, but it's not
any worse than before.
Author: Peter Geoghegan, slightly edited by me
Discussion: CAM3SWZS8RPvA=KFxADZWw3wAHnnbxMxDzkEC6fNaFc7zSm411w@mail.gmail.com
Backpatch: 9.5, where the feature was introduced
Remove HeapScanDescData.rs_initblock, which wasn't being used for anything
in the final version of the patch.
Fix IndexBuildHeapScan so that it supports syncscan again; the patch
broke synchronous scanning for index builds by forcing rs_startblk
to zero even when the caller did not care about that and had asked
for syncscan.
Add some commentary and usage defenses to heap_setscanlimits().
Fix heapam so that asking for rs_numblocks == 0 does what you would
reasonably expect. As coded it amounted to requesting a whole-table
scan, because those "--x <= 0" tests on an unsigned variable would
behave surprisingly.
In the passing, also move AT_ReAddComment to more logical position in the
enum, after all the Constraint-related subcommands.
This fixes a compiler warning, added by commit e42375fc. Backpatch to 9.5,
like that patch.
Previously, there was an inconsistency across json/jsonb operators that
operate on datums containing JSON arrays -- only some operators
supported negative array count-from-the-end subscripting. Specifically,
only a new-to-9.5 jsonb deletion operator had support (the new "jsonb -
integer" operator). This inconsistency seemed likely to be
counter-intuitive to users. To fix, allow all places where the user can
supply an integer subscript to accept a negative subscript value,
including path-orientated operators and functions, as well as other
extraction operators. This will need to be called out as an
incompatibility in the 9.5 release notes, since it's possible that users
are relying on certain established extraction operators changed here
yielding NULL in the event of a negative subscript.
For the json type, this requires adding a way of cheaply getting the
total JSON array element count ahead of time when parsing arrays with a
negative subscript involved, necessitating an ad-hoc lex and parse.
This is followed by a "conversion" from a negative subscript to its
equivalent positive-wise value using the count. From there on, it's as
if a positive-wise value was originally provided.
Note that there is still a minor inconsistency here across jsonb
deletion operators. Unlike the aforementioned new "-" deletion operator
that accepts an integer on its right hand side, the new "#-" path
orientated deletion variant does not throw an error when it appears like
an array subscript (input that could be recognized by as an integer
literal) is being used on an object, which is wrong-headed. The reason
for not being stricter is that it could be the case that an object pair
happens to have a key value that looks like an integer; in general,
these two possibilities are impossible to differentiate with rhs path
text[] argument elements. However, we still don't allow the "#-"
path-orientated deletion operator to perform array-style subscripting.
Rather, we just return the original left operand value in the event of a
negative subscript (which seems analogous to how the established
"jsonb/json #> text[]" path-orientated operator may yield NULL in the
event of an invalid subscript).
In passing, make SetArrayPath() stricter about not accepting cases where
there is trailing non-numeric garbage bytes rather than a clean NUL
byte. This means, for example, that strings like "10e10" are now not
accepted as an array subscript of 10 by some new-to-9.5 path-orientated
jsonb operators (e.g. the new #- operator). Finally, remove dead code
for jsonb subscript deletion; arguably, this should have been done in
commit b81c7b409.
Peter Geoghegan and Andrew Dunstan
This tells you what fraction of NOTIFY's queue is currently filled.
Brendan Jurd, reviewed by Merlin Moncure and Gurjeet Singh. A few
further tweaks by me.
Other options cannot be changed, as it's not totally clear if cached plans
would need to be invalidated if one of the other options change. Selectivity
estimator functions only change plan costs, not correctness of plans, so
those should be safe.
Original patch by Uriy Zhuravlev, heavily edited by me.
When a column's datatype is changed, ATExecAlterColumnType() rebuilds all
the affected indexes and constraints, and the comments from the old
indexes/constraints were not carried over.
To fix, create a synthetic COMMENT ON command in the work queue, to re-add
any comments on constraints. For indexes, there's a comment field in
IndexStmt that is used.
This fixes bug #13126, reported by Kirill Simonov. Original patch by
Michael Paquier, reviewed by Petr Jelinek and me. This bug is present in
all versions, but only backpatch to 9.5. Given how minor the issue is, it
doesn't seem worth the work and risk to backpatch further than that.
This formalizes a decision implicit in commit
4ea51cdfe8 and adds clean detection of
affected systems. Vendor updates are available for each such known bug.
Back-patch to 9.5, where the aforementioned commit first appeared.
This allows convenient checking for existence of a GUC from SQL, which is
particularly useful when dealing with custom variables.
David Christensen, reviewed by Jeevan Chalke
These variants used the old-style 'n'/' ' NULL indicators. The new-style
functions have been available since version 8.1. That should be long enough
that if there is still any old external code using these functions, they
can just switch to the new functions without worrying about backwards
compatibility
Peter Geoghegan
It's called "missing_ok" in the docs and in the C code.
I refrained from doing a catversion bump for this, because the name of an
input argument is just documentation, it has no effect on any callers.
Michael Paquier
Commit 179cdd09 added macros to check if a filename is a WAL segment
or other such file. However there were still some instances of the
strlen + strspn combination to check for that in WAL-related utilities
like pg_archivecleanup. Those checks can be replaced with the macros.
This patch makes use of the macros in those utilities and
which would make the code a bit easier to read.
Back-patch to 9.5.
Michael Paquier
Avoid memory leak from incorrect choice of how to free a StringInfo
(resetStringInfo doesn't do it). Now that pg_split_opts doesn't scribble
on the optstr, mark that as "const" for clarity. Attach the commentary in
protocol.sgml to the right place, and add documentation about the
user-visible effects of this change on postgres' -o option and libpq's
PGOPTIONS option.
_Asm_sched_fence() is just a compiler barrier, not a memory barrier. But
spinlock release on IA64 needs, at the very least, release
semantics. Use a full barrier instead.
This might be the cause for the occasional failures on buildfarm member
anole.
Discussion: 20150629101108.GB17640@alap3.anarazel.de
As first committed, this view reported on the file contents as they were
at the last SIGHUP event. That's not as useful as reporting on the current
contents, and what's more, it didn't work right on Windows unless the
current session had serviced at least one SIGHUP. Therefore, arrange to
re-read the files when pg_show_all_settings() is called. This requires
only minor refactoring so that we can pass changeVal = false to
set_config_option() so that it won't actually apply any changes locally.
In addition, add error reporting so that errors that would prevent the
configuration files from being loaded, or would prevent individual settings
from being applied, are visible directly in the view. This makes the view
usable for pre-testing whether edits made in the config files will have the
desired effect, before one actually issues a SIGHUP.
I also added an "applied" column so that it's easy to identify entries that
are superseded by later entries; this was the main use-case for the original
design, but it seemed unnecessarily hard to use for that.
Also fix a 9.4.1 regression that allowed multiple entries for a
PGC_POSTMASTER variable to cause bogus complaints in the postmaster log.
(The issue here was that commit bf007a27ac unintentionally reverted
3e3f65973a, which suppressed any duplicate entries within
ParseConfigFp. However, since the original coding of the pg_file_settings
view depended on such suppression *not* happening, we couldn't have fixed
this issue now without first doing something with pg_file_settings.
Now we suppress duplicates by marking them "ignored" within
ProcessConfigFileInternal, which doesn't hide them in the view.)
Lesser changes include:
Drive the view directly off the ConfigVariable list, instead of making a
basically-equivalent second copy of the data. There's no longer any need
to hang onto the data permanently, anyway.
Convert show_all_file_settings() to do its work in one call and return a
tuplestore; this avoids risks associated with assuming that the GUC state
will hold still over the course of query execution. (I think there were
probably latent bugs here, though you might need something like a cursor
on the view to expose them.)
Arrange to run SIGHUP processing in a short-lived memory context, to
forestall process-lifespan memory leaks. (There is one known leak in this
code, in ProcessConfigDirectory; it seems minor enough to not be worth
back-patching a specific fix for.)
Remove mistaken assignment to ConfigFileLineno that caused line counting
after an include_dir directive to be completely wrong.
Add missed failure check in AlterSystemSetConfigFile(). We don't really
expect ParseConfigFp() to fail, but that's not an excuse for not checking.
This makes it possible to use the functions without getting errors, if there
is a chance that the file might be removed or renamed concurrently.
pg_rewind needs to do just that, although this could be useful for other
purposes too. (The changes to pg_rewind to use these functions will come in
a separate commit.)
The read_binary_file() function isn't very well-suited for extensions.c's
purposes anymore, if it ever was. So bite the bullet and make a copy of it
in extension.c, tailored for that use case. This seems better than the
accidental code reuse, even if it's a some more lines of code.
Michael Paquier, with plenty of kibitzing by me.
Commit b89e151054 added the
ResolveCminCmaxDuringDecoding declaration to tqual.h, which uses an
HTAB parameter, without declaring HTAB. It accidentally fails to
fail to build with current sources because a declaration happens to
be included, directly or indirectly, in all source files that
currently use tqual.h before tqual.h is first included, but we
shouldn't count on that. Since an opaque declaration is enough
here, just use that, as was done in snapmgr.h.
Backpatch to 9.4, where the HTAB reference was added to tqual.h.
Commit b488c580ae, which added the DDL command collection feature,
neglected to update the code that commit cac7658205 had previously
added two weeks earlier for the TRANSFORM feature.
Reported by Michael Paquier.
Don't apply rmtree(), which will gleefully remove an entire subtree,
and don't even apply unlink() unless it's symlink or a directory,
the only things that we expect to find.
Amit Kapila, with minor tweaks by me, per extensive discussions
involving Andrew Dunstan, Fujii Masao, and Heikki Linnakangas,
at least some of whom also reviewed the code.
Allow CustomPath to have a list of paths, CustomPlan a list of plans,
and CustomPlanState a list of planstates known to the core system, so
that custom path/plan providers can more reasonably use this
infrastructure for nodes with multiple children.
KaiGai Kohei, per a design suggestion from Tom Lane, with some
further kibitzing by me.
Commit f3b5565dd4 was a couple of bricks shy
of a load; specifically, it missed putting pg_trigger_tgrelid_tgname_index
into the relcache init file, because that index is not used by any
syscache. However, we have historically nailed that index into cache for
performance reasons. The upshot was that load_relcache_init_file always
decided that the init file was busted and silently ignored it, resulting
in a significant hit to backend startup speed.
To fix, reinstantiate RelationIdIsInInitFile() as a wrapper around
RelationSupportsSysCache(), which can know about additional relations
that should be in the init file despite being unknown to syscache.c.
Also install some guards against future mistakes of this type: make
write_relcache_init_file Assert that all nailed relations get written to
the init file, and make load_relcache_init_file emit a WARNING if it takes
the "wrong number of nailed relations" exit path. Now that we remove the
init files during postmaster startup, that case should never occur in the
field, even if we are starting a minor-version update that added or removed
rels from the nailed set. So the warning shouldn't ever be seen by end
users, but it will show up in the regression tests if somebody breaks this
logic.
Back-patch to all supported branches, like the previous commit.
After the archiver dies, postmaster tries to start a new one immediately.
But previously this could happen only while server was running normally
even though archiving was enabled always (i.e., archive_mode was set to
always). So the archiver running during recovery could not restart soon
after it died. This is an oversight in commit ffd3774.
This commit changes reaper(), postmaster's signal handler to cleanup
after a child process dies, so that it tries to a new archiver even during
recovery if necessary.
Patch by me. Review by Alvaro Herrera.
Following recent discussion on -hackers. The underlying function is
also renamed to jsonb_delete_path. The regression tests now don't need
ugly type casts to avoid the ambiguity, so they are also removed.
Catalog version bumped.
When we invalidate the relcache entry for a system catalog or index, we
must also delete the relcache "init file" if the init file contains a copy
of that rel's entry. The old way of doing this relied on a specially
maintained list of the OIDs of relations present in the init file: we made
the list either when reading the file in, or when writing the file out.
The problem is that when writing the file out, we included only rels
present in our local relcache, which might have already suffered some
deletions due to relcache inval events. In such cases we correctly decided
not to overwrite the real init file with incomplete data --- but we still
used the incomplete initFileRelationIds list for the rest of the current
session. This could result in wrong decisions about whether the session's
own actions require deletion of the init file, potentially allowing an init
file created by some other concurrent session to be left around even though
it's been made stale.
Since we don't support changing the schema of a system catalog at runtime,
the only likely scenario in which this would cause a problem in the field
involves a "vacuum full" on a catalog concurrently with other activity, and
even then it's far from easy to provoke. Remarkably, this has been broken
since 2002 (in commit 7863404417), but we had
never seen a reproducible test case until recently. If it did happen in
the field, the symptoms would probably involve unexpected "cache lookup
failed" errors to begin with, then "could not open file" failures after the
next checkpoint, as all accesses to the affected catalog stopped working.
Recovery would require manually removing the stale "pg_internal.init" file.
To fix, get rid of the initFileRelationIds list, and instead consult
syscache.c's list of relations used in catalog caches to decide whether a
relation is included in the init file. This should be a tad more efficient
anyway, since we're replacing linear search of a list with ~100 entries
with a binary search. It's a bit ugly that the init file contents are now
so directly tied to the catalog caches, but in practice that won't make
much difference.
Back-patch to all supported branches.
When the inner side of a nestloop SEMI or ANTI join is an indexscan that
uses all the join clauses as indexquals, it can be presumed that both
matched and unmatched outer rows will be processed very quickly: for
matched rows, we'll stop after fetching one row from the indexscan, while
for unmatched rows we'll have an indexscan that finds no matching index
entries, which should also be quick. The planner already knew about this,
but it was nonetheless charging for at least one full run of the inner
indexscan, as a consequence of concerns about the behavior of materialized
inner scans --- but those concerns don't apply in the fast case. If the
inner side has low cardinality (many matching rows) this could make an
indexscan plan look far more expensive than it actually is. To fix,
rearrange the work in initial_cost_nestloop/final_cost_nestloop so that we
don't add the inner scan cost until we've inspected the indexquals, and
then we can add either the full-run cost or just the first tuple's cost as
appropriate.
Experimentation with this fix uncovered another problem: add_path and
friends were coded to disregard cheap startup cost when considering
parameterized paths. That's usually okay (and desirable, because it thins
the path herd faster); but in this fast case for SEMI/ANTI joins, it could
result in throwing away the desired plain indexscan path in favor of a
bitmap scan path before we ever get to the join costing logic. In the
many-matching-rows cases of interest here, a bitmap scan will do a lot more
work than required, so this is a problem. To fix, add a per-relation flag
consider_param_startup that works like the existing consider_startup flag,
but applies to parameterized paths, and set it for relations that are the
inside of a SEMI or ANTI join.
To make this patch reasonably safe to back-patch, care has been taken to
avoid changing the planner's behavior except in the very narrow case of
SEMI/ANTI joins with inner indexscans. There are places in
compare_path_costs_fuzzily and add_path_precheck that are not terribly
consistent with the new approach, but changing them will affect planner
decisions at the margins in other cases, so we'll leave that for a
HEAD-only fix.
Back-patch to 9.3; before that, the consider_startup flag didn't exist,
meaning that the second aspect of the patch would be too invasive.
Per a complaint from Peter Holzer and analysis by Tomas Vondra.
The function is given a fourth parameter, which defaults to true. When
this parameter is true, if the last element of the path is missing
in the original json, jsonb_set creates it in the result and assigns it
the new value. If it is false then the function does nothing unless all
elements of the path are present, including the last.
Based on some original code from Dmitry Dolgov, heavily modified by me.
Catalog version bumped.
opr_sanity.sql has a test checking that relevant properties of built-in
functions match when the same C function is referenced by multiple pg_proc
entries. The test neglected to check proleakproof, though, and when
I added that condition it exposed that xideqint4 hadn't been updated to
match xideq. So fix that as well, and in consequence bump catversion.
This isn't very critical, so no need to worry about fixing back branches.
This undoes a poorly-thought-out choice in commit 970a18687f, namely
to export guc.c's internal variable data_directory. The authoritative
variable so far as C code is concerned is DataDir; there is no reason for
anything except specific bits of GUC code to look at the GUC variable.
After yesterday's commits fixing the fsync-on-restart patch, the only
remaining misuse of data_directory was in AlterSystemSetConfigFile(),
which would be much better off just using a relative path anyhow: it's
less code and it doesn't break if the DBA moves the data directory of a
running system, which is a case we've taken some pains over in the past.
This is mostly cosmetic, so no need for a back-patch (and I'd be hesitant
to remove a global variable in stable branches anyway).
Commit 2ce439f337 introduced a rather serious
regression, namely that if its scan of the data directory came across any
un-fsync-able files, it would fail and thereby prevent database startup.
Worse yet, symlinks to such files also caused the problem, which meant that
crash restart was guaranteed to fail on certain common installations such
as older Debian.
After discussion, we agreed that (1) failure to start is worse than any
consequence of not fsync'ing is likely to be, therefore treat all errors
in this code as nonfatal; (2) we should not chase symlinks other than
those that are expected to exist, namely pg_xlog/ and tablespace links
under pg_tblspc/. The latter restriction avoids possibly fsync'ing a
much larger part of the filesystem than intended, if the user has left
random symlinks hanging about in the data directory.
This commit takes care of that and also does some code beautification,
mainly moving the relevant code into fd.c, which seems a much better place
for it than xlog.c, and making sure that the conditional compilation for
the pre_sync_fname pass has something to do with whether pg_flush_data
works.
I also relocated the call site in xlog.c down a few lines; it seems a
bit silly to be doing this before ValidateXLOGDirectoryStructure().
The similar logic in initdb.c ought to be made to match this, but that
change is noncritical and will be dealt with separately.
Back-patch to all active branches, like the prior commit.
Abhijit Menon-Sen and Tom Lane
Remove a bunch of "extern Datum foo(PG_FUNCTION_ARGS);" declarations that
are no longer needed now that PG_FUNCTION_INFO_V1(foo) provides that.
Some of these were evidently missed in commit e7128e8dbb, but others
were cargo-culted in in code added since then. Possibly that can be blamed
in part on the fact that we'd not fixed relevant documentation examples,
which I've now done.
Fix confusion in documentation, substantial memory leakage if float8 or
float4 are pass-by-reference, and assorted comments that were obsoleted
by commit 98edd617f3.
Previously, INSERT with ON CONFLICT DO UPDATE specified used a new
command tag -- UPSERT. It was introduced out of concern that INSERT as
a command tag would be a misrepresentation for ON CONFLICT DO UPDATE, as
some affected rows may actually have been updated.
Alvaro Herrera noticed that the implementation of that new command tag
was incomplete; in subsequent discussion we concluded that having it
doesn't provide benefits that are in line with the compatibility breaks
it requires.
Catversion bump due to the removal of PlannedStmt->isUpsert.
Author: Peter Geoghegan
Discussion: 20150520215816.GI5885@postgresql.org
pushJsonbValue was accepting jbvBinary objects passed as WJB_ELEM or
WJB_VALUE data. While this succeeded, when those objects were later
encountered in attempting to convert the result to Jsonb, errors
occurred. With this change we ghuarantee that a JSonbValue constructed
from calls to pushJsonbValue does not contain any jbvBinary objects.
This cures a problem observed with jsonb_delete.
This means callers of pushJsonbValue no longer need to perform this
unpacking themselves. A subsequent patch will perform some cleanup in
that area.
The error was not triggered by any 9.4 code, but this is a publicly
visible routine, and so the error could be exercised by third party
code, therefore backpatch to 9.4.
Bug report from Peter Geoghegan, fix by me.
With commit de768844, a copy of the partial segment was archived with the
.partial suffix, but the original file was still left in pg_xlog, so it
didn't actually solve the problems with archiving the partial segment that
it was supposed to solve. With this patch, the partial segment is renamed
rather than copied, so we only archive it with the .partial suffix.
Also be more robust in detecting if the last segment is already being
archived. Previously I used XLogArchiveIsBusy() for that, but that's not
quite right. With archive_mode='always', there might be a .ready file for
it, and we don't want to rename it to .partial in that case.
The old segment is needed until we're fully committed to the new timeline,
i.e. until we've written the end-of-recovery WAL record and updated the
min recovery point and timeline in the control file. So move the renaming
later in the startup sequence, after all that's been done.
Paul Ramsey reported that commit 35fcb1b3d0
induced a core dump on commuted ORDER BY expressions, because it was
assuming that the indexorderby expression could be found verbatim in the
relevant equivalence class, but it wasn't there. We really don't need
anything that complicated anyway; for the data types likely to be used for
index ORDER BY operators in the foreseeable future, the exprType() of the
ORDER BY expression will serve fine. (The case where we'd have to work
harder is where the ORDER BY expression's result is only binary-compatible
with the declared input type of the ordering operator; long before worrying
about that, one would need to get rid of GiST's hard-wired assumption that
said datatype is float8.)
Aside from fixing that crash and adding a regression test for the case,
I did some desultory code review:
nodeIndexscan.c was likewise overthinking how hard it ought to work to
identify the datatype of the ORDER BY expressions.
Add comments explaining how come nodeIndexscan.c can get away with
simplifying assumptions about NULLS LAST ordering and no backward scan.
Revert no-longer-needed changes of find_ec_member_for_tle(); while the
new definition was no worse than the old, it wasn't better either, and
it might cause back-patching pain.
Revert entirely bogus additions to genam.h.
We want this struct to be exactly a series of 3 int16 words, no more
and no less. Historically, at least, some ARM compilers preferred to
pad it to 8 bytes unless coerced. Our old way of doing that was just
to use __attribute__((packed)), but as pointed out by Piotr Stefaniak,
that does too much: it also licenses the compiler to give the struct
only byte-alignment. We don't want that because it adds access overhead,
possibly quite significant overhead. According to the GCC manual, what
we want requires also specifying __attribute__((align(2))). It's not
entirely clear if all the relevant compilers accept this pragma as well,
but we can hope the buildfarm will tell us if not. We can also add a
static assertion that should fire if the compiler padded the struct.
Since the combination of these pragmas should define exactly what we
want on any compiler that accepts them, let's try using them wherever
we think they exist, not only for __arm__. (This is likely to expose
that the conditional definitions in c.h are inadequate, but finding
that out would be a good thing.)
The immediate motivation for this is that the current definition of
ExecRowMark allows its curCtid field to be misaligned. It is not clear
whether there are any other uses of ItemPointerData with a similar hazard.
We could change the definition of ExecRowMark if this doesn't work, but
it would be far better to have a future-proof fix.
Piotr Stefaniak, some further hacking by me
Use "a" and "an" correctly, mostly in comments. Two error messages were
also fixed (they were just elogs, so no translation work required). Two
function comments in pg_proc.h were also fixed. Etsuro Fujita reported one
of these, but I found a lot more with grep.
Also fix a few other typos spotted while grepping for the a/an typos.
For example, "consists out of ..." -> "consists of ...". Plus a "though"/
"through" mixup reported by Euler Taveira.
Many of these typos were in old code, which would be nice to backpatch to
make future backpatching easier. But much of the code was new, and I didn't
feel like crafting separate patches for each branch. So no backpatching.
This reverts commit 16304a0134, except
for its changes in src/port/snprintf.c; as well as commit
cac18a76bb which is no longer needed.
Fujii Masao reported that the previous commit caused failures in psql on
OS X, since if one exits the pager program early while viewing a query
result, psql sees an EPIPE error from fprintf --- and the wrapper function
thought that was reason to panic. (It's a bit surprising that the same
does not happen on Linux.) Further discussion among the security list
concluded that the risk of other such failures was far too great, and
that the one-size-fits-all approach to error handling embodied in the
previous patch is unlikely to be workable.
This leaves us again exposed to the possibility of the type of failure
envisioned in CVE-2015-3166. However, that failure mode is strictly
hypothetical at this point: there is no concrete reason to believe that
an attacker could trigger information disclosure through the supposed
mechanism. In the first place, the attack surface is fairly limited,
since so much of what the backend does with format strings goes through
stringinfo.c or psprintf(), and those already had adequate defenses.
In the second place, even granting that an unprivileged attacker could
control the occurrence of ENOMEM with some precision, it's a stretch to
believe that he could induce it just where the target buffer contains some
valuable information. So we concluded that the risk of non-hypothetical
problems induced by the patch greatly outweighs the security risks.
We will therefore revert, and instead undertake closer analysis to
identify specific calls that may need hardening, rather than attempt a
universal solution.
We have kept the portion of the previous patch that improved snprintf.c's
handling of errors when it calls the platform's sprintf(). That seems to
be an unalloyed improvement.
Security: CVE-2015-3166
Defer lookup of opfamily and input type of a of a user specified opclass
until the optimizer selects among available unique indexes; and store
the opclass in the parse analyzed tree instead. The primary reason for
doing this is that for rule deparsing it's easier to use the opclass
than the previous representation.
While at it also rename a variable in the inference code to better fit
it's purpose.
This is separate from the actual fixes for deparsing to make review
easier.
No index in template0 should have collation-dependent ordering, especially
not indexes on shared catalogs. For most textual columns we avoid this
issue by using type "name" (which sorts per strcmp()). However there are a
few indexed columns that we'd prefer to use "text" for, and for that, the
default opclass text_ops is unsafe. Fortunately, text_pattern_ops is safe
(it sorts per memcmp()), and it has no real functional disadvantage for our
purposes. So change the indexes on pg_seclabel.provider and
pg_shseclabel.provider to use text_pattern_ops.
In passing, also mark pg_replication_origin.roname as using
text_pattern_ops --- for some reason it was labeled varchar_pattern_ops
which is just wrong, even though it accidentally worked.
Add regression test queries to catch future errors of these kinds.
We still can't do anything about the misdeclared pg_seclabel and
pg_shseclabel indexes in back branches :-(
These were "text", but that's a bad idea because it has collation-dependent
ordering. No index in template0 should have collation-dependent ordering,
especially not indexes on shared catalogs. There was general agreement
that provider names don't need to be longer than other identifiers, so we
can fix this at a small waste of table space by changing from text to name.
There's no way to fix the problem in the back branches, but we can hope
that security labels don't yet have widespread-enough usage to make it
urgent to fix.
There needs to be a regression sanity test to prevent us from making this
same mistake again; but before putting that in, we'll need to get rid of
similar brain fade in the recently-added pg_replication_origin catalog.
Note: for lack of a suitable testing environment, I've not really exercised
this change. I trust the buildfarm will show up any mistakes.
Commit 83e176ec18 removed the longstanding
support functions for block sampling without any consideration of the
impact this would have on third-party FDWs. The new API is not notably
more functional for FDWs than the old, so forcing them to change doesn't
seem like a good thing. We can provide the old API as a wrapper (more
or less) around the new one for a minimal amount of extra code.
All known standard library implementations of these functions can fail
with ENOMEM. A caller neglecting to check for failure would experience
missing output, information exposure, or a crash. Check return values
within wrappers and code, currently just snprintf.c, that bypasses the
wrappers. The wrappers do not return after an error, so their callers
need not check. Back-patch to 9.0 (all supported versions).
Popular free software standard library implementations do take pains to
bypass malloc() in simple cases, but they risk ENOMEM for floating point
numbers, positional arguments, large field widths, and large precisions.
No specification demands such caution, so this commit regards every call
to a printf family function as a potential threat.
Injecting the wrappers implicitly is a compromise between patch scope
and design goals. I would prefer to edit each call site to name a
wrapper explicitly. libpq and the ECPG libraries would, ideally, convey
errors to the caller rather than abort(). All that would be painfully
invasive for a back-patched security fix, hence this compromise.
Security: CVE-2015-3166
This oversight results in a crash at executor startup if the plan has
been copied. outfuncs.c was missed as well.
While we could probably have taught both those files to cope with the
originally chosen representation of an Oid array, it would have been
painful, not least because there'd be no easy way to verify the array
length. An Oid List is far easier to work with. And AFAICS, there is
no particular notational benefit to using an array rather than a list
in the existing parts of the patch either. So just change it to a list.
Error in commit 35fcb1b3d0, which is new,
so no need for back-patch.
This SQL standard functionality allows to aggregate data by different
GROUP BY clauses at once. Each grouping set returns rows with columns
grouped by in other sets set to NULL.
This could previously be achieved by doing each grouping as a separate
query, conjoined by UNION ALLs. Besides being considerably more concise,
grouping sets will in many cases be faster, requiring only one scan over
the underlying data.
The current implementation of grouping sets only supports using sorting
for input. Individual sets that share a sort order are computed in one
pass. If there are sets that don't share a sort order, additional sort &
aggregation steps are performed. These additional passes are sourced by
the previous sort step; thus avoiding repeated scans of the source data.
The code is structured in a way that adding support for purely using
hash aggregation or a mix of hashing and sorting is possible. Sorting
was chosen to be supported first, as it is the most generic method of
implementation.
Instead of, as in an earlier versions of the patch, representing the
chain of sort and aggregation steps as full blown planner and executor
nodes, all but the first sort are performed inside the aggregation node
itself. This avoids the need to do some unusual gymnastics to handle
having to return aggregated and non-aggregated tuples from underlying
nodes, as well as having to shut down underlying nodes early to limit
memory usage. The optimizer still builds Sort/Agg node to describe each
phase, but they're not part of the plan tree, but instead additional
data for the aggregation node. They're a convenient and preexisting way
to describe aggregation and sorting. The first (and possibly only) sort
step is still performed as a separate execution step. That retains
similarity with existing group by plans, makes rescans fairly simple,
avoids very deep plans (leading to slow explains) and easily allows to
avoid the sorting step if the underlying data is sorted by other means.
A somewhat ugly side of this patch is having to deal with a grammar
ambiguity between the new CUBE keyword and the cube extension/functions
named cube (and rollup). To avoid breaking existing deployments of the
cube extension it has not been renamed, neither has cube been made a
reserved keyword. Instead precedence hacking is used to make GROUP BY
cube(..) refer to the CUBE grouping sets feature, and not the function
cube(). To actually group by a function cube(), unlikely as that might
be, the function name has to be quoted.
Needs a catversion bump because stored rules may change.
Author: Andrew Gierth and Atri Sharma, with contributions from Andres Freund
Reviewed-By: Andres Freund, Noah Misch, Tom Lane, Svenne Krap, Tomas
Vondra, Erik Rijkers, Marti Raudsepp, Pavel Stehule
Discussion: CAOeZVidmVRe2jU6aMk_5qkxnB7dfmPROzM7Ur8JPW5j8Y5X-Lw@mail.gmail.com
This lets BRIN be used with R-Tree-like indexing strategies.
Also provided are operator classes for range types, box and inet/cidr.
The infrastructure provided here should be sufficient to create operator
classes for similar datatypes; for instance, opclasses for PostGIS
geometries should be doable, though we didn't try to implement one.
(A box/point opclass was also submitted, but we ripped it out before
commit because the handling of floating point comparisons in existing
code is inconsistent and would generate corrupt indexes.)
Author: Emre Hasegeli. Cosmetic changes by me
Review: Andreas Karlsson
For upcoming BRIN opclasses, it's convenient to have strategy numbers
defined in a single place. Since there's nothing appropriate, create
it. The StrategyNumber typedef now lives there, as well as existing
strategy numbers for B-trees (from skey.h) and R-tree-and-friends (from
gist.h). skey.h is forced to include stratnum.h because of the
StrategyNumber typedef, but gist.h is not; extensions that currently
rely on gist.h for rtree strategy numbers might need to add a new
A few .c files can stop including skey.h and/or gist.h, which is a nice
side benefit.
Per discussion:
https://www.postgresql.org/message-id/20150514232132.GZ2523@alvh.no-ip.org
Authored by Emre Hasegeli and Álvaro.
(It's not clear to me why bootscanner.l has any #include lines at all.)
Add a TABLESAMPLE clause to SELECT statements that allows
user to specify random BERNOULLI sampling or block level
SYSTEM sampling. Implementation allows for extensible
sampling functions to be written, using a standard API.
Basic version follows SQLStandard exactly. Usable
concrete use cases for the sampling API follow in later
commits.
Petr Jelinek
Reviewed by Michael Paquier and Simon Riggs
We can only support a lossy distance function when the distance function's
datatype is comparable with the original ordering operator's datatype.
The distance function always returns a float8, so we are limited to float8,
and float4 (by a hard-coded cast of the float8 to float4).
In light of this limitation, it seems like a good idea to have a separate
'recheck' flag for the ORDER BY expressions, so that if you have a non-lossy
distance function, it still works with lossy quals. There are cases like
that with the build-in or contrib opclasses, but it's plausible.
There was a hidden assumption that the ORDER BY values returned by GiST
match the original ordering operator's return type, but there are plenty
of examples where that's not true, e.g. in btree_gist and pg_trgm. As long
as the distance function is not lossy, we can tolerate that and just not
return the distance to the executor (or rather, always return NULL). The
executor doesn't need the distances if there are no lossy results.
There was another little bug: the recheck variable was not initialized
before calling the distance function. That revealed the bigger issue,
as the executor tried to reorder tuples that didn't need reordering, and
that failed because of the datatype mismatch.
The distance function can now set *recheck = false, like index quals. The
executor will then re-check the ORDER BY expressions, and use a queue to
reorder the results on the fly.
This makes it possible to do kNN-searches on polygons and circles, which
don't store the exact value in the index, but just a bounding box.
Alexander Korotkov and me
When this option is specified, a progress report is printed as each index
is reindexed.
Per discussion, we agreed on the following syntax for the extensibility of
the options.
REINDEX (flexible options) { INDEX | ... } name
Sawada Masahiko.
Reviewed by Robert Haas, Fabrízio Mello, Alvaro Herrera, Kyotaro Horiguchi,
Jim Nasby and me.
Discussion: CAD21AoA0pK3YcOZAFzMae+2fcc3oGp5zoRggDyMNg5zoaWDhdQ@mail.gmail.com
Until now, these functions have only supported encoding conversions using
lookup tables, which is fine as long as there's not too many code points
to convert. However, GB18030 expects all 1.1 million Unicode code points
to be convertible, which would require a ridiculously-sized lookup table.
Fortunately, a large fraction of those conversions can be expressed through
arithmetic, ie the conversions are one-to-one in certain defined ranges.
To support that, provide a callback function that is used after consulting
the lookup tables. (This patch doesn't actually change anything about the
GB18030 conversion behavior, just provide infrastructure for fixing it.)
Since this requires changing the APIs of UtfToLocal/LocalToUtf anyway,
take the opportunity to rearrange their argument lists into what seems
to me a saner order. And beautify the call sites by using lengthof()
instead of error-prone sizeof() arithmetic.
In passing, also mark all the lookup tables used by these calls "const".
This moves an impressive amount of stuff into the text segment, at least
on my machine, and is safer anyhow.
This patch introduces the ability for complex datatypes to have an
in-memory representation that is different from their on-disk format.
On-disk formats are typically optimized for minimal size, and in any case
they can't contain pointers, so they are often not well-suited for
computation. Now a datatype can invent an "expanded" in-memory format
that is better suited for its operations, and then pass that around among
the C functions that operate on the datatype. There are also provisions
(rudimentary as yet) to allow an expanded object to be modified in-place
under suitable conditions, so that operations like assignment to an element
of an array need not involve copying the entire array.
The initial application for this feature is arrays, but it is not hard
to foresee using it for other container types like JSON, XML and hstore.
I have hopes that it will be useful to PostGIS as well.
In this initial implementation, a few heuristics have been hard-wired
into plpgsql to improve performance for arrays that are stored in
plpgsql variables. We would like to generalize those hacks so that
other datatypes can obtain similar improvements, but figuring out some
appropriate APIs is left as a task for future work. (The heuristics
themselves are probably not optimal yet, either, as they sometimes
force expansion of arrays that would be better left alone.)
Preliminary performance testing shows impressive speed gains for plpgsql
functions that do element-by-element access or update of large arrays.
There are other cases that get a little slower, as a result of added array
format conversions; but we can hope to improve anything that's annoyingly
bad. In any case most applications should see a net win.
Tom Lane, reviewed by Andres Freund
jsonb_pretty(jsonb) produces nicely indented json output.
jsonb || jsonb concatenates two jsonb values.
jsonb - text removes a key and its associated value from the json
jsonb - int removes the designated array element
jsonb - text[] removes a key and associated value or array element at
the designated path
jsonb_replace(jsonb,text[],jsonb) replaces the array element designated
by the path or the value associated with the key designated by the path
with the given value.
Original work by Dmitry Dolgov, adapted and reworked for PostgreSQL core
by Andrew Dunstan, reviewed and tidied up by Petr Jelinek.
Previously, FDWs could only do "early row locking", that is lock a row as
soon as it's fetched, even though local restriction/join conditions might
discard the row later. This patch adds callbacks that allow FDWs to do
late locking in the same way that it's done for regular tables.
To make use of this feature, an FDW must support the "ctid" column as a
unique row identifier. Currently, since ctid has to be of type TID,
the feature is of limited use, though in principle it could be used by
postgres_fdw. We may eventually allow FDWs to specify another data type
for ctid, which would make it possible for more FDWs to use this feature.
This commit does not modify postgres_fdw to use late locking. We've
tested some prototype code for that, but it's not in committable shape,
and besides it's quite unclear whether it actually makes sense to do late
locking against a remote server. The extra round trips required are likely
to outweigh any benefit from improved concurrency.
Etsuro Fujita, reviewed by Ashutosh Bapat, and hacked up a lot by me
Windows can't reliably restore symbolic links from a tar format, so
instead during backup start we create a tablespace_map file, which is
used by the restoring postgres to create the correct links in pg_tblspc.
The backup protocol also now has an option to request this file to be
included in the backup stream, and this is used by pg_basebackup when
operating in tar mode.
This is done on all platforms, not just Windows.
This means that pg_basebackup will not not work in tar mode against 9.4
and older servers, as this protocol option isn't implemented there.
Amit Kapila, reviewed by Dilip Kumar, with a little editing from me.
This feature lets user code inspect and take action on DDL events.
Whenever a ddl_command_end event trigger is installed, DDL actions
executed are saved to a list which can be inspected during execution of
a function attached to ddl_command_end.
The set-returning function pg_event_trigger_ddl_commands can be used to
list actions so captured; it returns data about the type of command
executed, as well as the affected object. This is sufficient for many
uses of this feature. For the cases where it is not, we also provide a
"command" column of a new pseudo-type pg_ddl_command, which is a
pointer to a C structure that can be accessed by C code. The struct
contains all the info necessary to completely inspect and even
reconstruct the executed command.
There is no actual deparse code here; that's expected to come later.
What we have is enough infrastructure that the deparsing can be done in
an external extension. The intention is that we will add some deparsing
code in a later release, as an in-core extension.
A new test module is included. It's probably insufficient as is, but it
should be sufficient as a starting point for a more complete and
future-proof approach.
Authors: Álvaro Herrera, with some help from Andres Freund, Ian Barwick,
Abhijit Menon-Sen.
Reviews by Andres Freund, Robert Haas, Amit Kapila, Michael Paquier,
Craig Ringer, David Steele.
Additional input from Chris Browne, Dimitri Fontaine, Stephen Frost,
Petr Jelínek, Tom Lane, Jim Nasby, Steven Singer, Pavel Stěhule.
Based on original work by Dimitri Fontaine, though I didn't use his
code.
Discussion:
https://www.postgresql.org/message-id/m2txrsdzxa.fsf@2ndQuadrant.frhttps://www.postgresql.org/message-id/20131108153322.GU5809@eldon.alvh.no-ip.orghttps://www.postgresql.org/message-id/20150215044814.GL3391@alvh.no-ip.org
Commit e7cb7ee145 included some design
decisions that seem pretty questionable to me, and there was quite a lot
of stuff not to like about the documentation and comments. Clean up
as follows:
* Consider foreign joins only between foreign tables on the same server,
rather than between any two foreign tables with the same underlying FDW
handler function. In most if not all cases, the FDW would simply have had
to apply the same-server restriction itself (far more expensively, both for
lack of caching and because it would be repeated for each combination of
input sub-joins), or else risk nasty bugs. Anyone who's really intent on
doing something outside this restriction can always use the
set_join_pathlist_hook.
* Rename fdw_ps_tlist/custom_ps_tlist to fdw_scan_tlist/custom_scan_tlist
to better reflect what they're for, and allow these custom scan tlists
to be used even for base relations.
* Change make_foreignscan() API to include passing the fdw_scan_tlist
value, since the FDW is required to set that. Backwards compatibility
doesn't seem like an adequate reason to expect FDWs to set it in some
ad-hoc extra step, and anyway existing FDWs can just pass NIL.
* Change the API of path-generating subroutines of add_paths_to_joinrel,
and in particular that of GetForeignJoinPaths and set_join_pathlist_hook,
so that various less-used parameters are passed in a struct rather than
as separate parameter-list entries. The objective here is to reduce the
probability that future additions to those parameter lists will result in
source-level API breaks for users of these hooks. It's possible that this
is even a small win for the core code, since most CPU architectures can't
pass more than half a dozen parameters efficiently anyway. I kept root,
joinrel, outerrel, innerrel, and jointype as separate parameters to reduce
code churn in joinpath.c --- in particular, putting jointype into the
struct would have been problematic because of the subroutines' habit of
changing their local copies of that variable.
* Avoid ad-hocery in ExecAssignScanProjectionInfo. It was probably all
right for it to know about IndexOnlyScan, but if the list is to grow
we should refactor the knowledge out to the callers.
* Restore nodeForeignscan.c's previous use of the relcache to avoid
extra GetFdwRoutine lookups for base-relation scans.
* Lots of cleanup of documentation and missed comments. Re-order some
code additions into more logical places.
The new type has the scope of whole the database cluster so it doesn't
behave the same as the existing OID alias types which have database
scope,
concerning object dependency. To avoid confusion constants of the new
type are prohibited from appearing where dependencies are made involving
it.
Also, add a note to the docs about possible MVCC violation and
optimization issues, which are general over the all reg* types.
Kyotaro Horiguchi
The function and view added here provide a way to look at all settings
in postgresql.conf, any #include'd files, and postgresql.auto.conf
(which is what backs the ALTER SYSTEM command).
The information returned includes the configuration file name, line
number in that file, sequence number indicating when the parameter is
loaded (useful to see if it is later masked by another definition of the
same parameter), parameter name, and what it is set to at that point.
This information is updated on reload of the server.
This is unfiltered, privileged, information and therefore access is
restricted to superusers through the GRANT system.
Author: Sawada Masahiko, various improvements by me.
Reviewers: David Steele
Previously, we would archive the possible-incomplete WAL segment with its
normal filename, but that causes trouble if the server owning that timeline
is still running, and tries to archive the same segment later. It's not nice
for the standby to trip up the master's archival like that. And it's pretty
confusing, anyway, to have an incomplete segment in the archive that's
indistinguishable from a normal, complete segment.
To avoid such confusion, add a .partial suffix to the file. Or to be more
precise, make a copy of the old segment under the .partial suffix, and
archive that instead of the original file. pg_receivexlog also uses the
.partial suffix for the same purpose, to tell apart incompletely streamed
files from complete ones.
There is no automatic mechanism to use the .partial files at recovery, so
they will go unused, unless the administrator manually copies to them to
the pg_xlog directory (and removes the .partial suffix). Recovery won't
normally need the WAL - when recovering to the new timeline, it will find
the same WAL on the first segment on the new timeline instead - but it
nevertheless feels better to archive the file with the .partial suffix, for
debugging purposes if nothing else.
The logic introduced in commit b69bf30b9b
and repaired in commits 669c7d20e6 and
7be47c56af helps to ensure that we don't
overwrite old multixact member information while it is still needed,
but a user who creates many large multixacts can still exhaust the
member space (and thus start getting errors) while autovacuum stands
idly by.
To fix this, progressively ramp down the effective value (but not the
actual contents) of autovacuum_multixact_freeze_max_age as member space
utilization increases. This makes autovacuum more aggressive and also
reduces the threshold for a manual VACUUM to perform a full-table scan.
This patch leaves unsolved the problem of ensuring that emergency
autovacuums are triggered even when autovacuum=off. We'll need to fix
that via a separate patch.
Thomas Munro and Robert Haas
The newly added ON CONFLICT clause allows to specify an alternative to
raising a unique or exclusion constraint violation error when inserting.
ON CONFLICT refers to constraints that can either be specified using a
inference clause (by specifying the columns of a unique constraint) or
by naming a unique or exclusion constraint. DO NOTHING avoids the
constraint violation, without touching the pre-existing row. DO UPDATE
SET ... [WHERE ...] updates the pre-existing tuple, and has access to
both the tuple proposed for insertion and the existing tuple; the
optional WHERE clause can be used to prevent an update from being
executed. The UPDATE SET and WHERE clauses have access to the tuple
proposed for insertion using the "magic" EXCLUDED alias, and to the
pre-existing tuple using the table name or its alias.
This feature is often referred to as upsert.
This is implemented using a new infrastructure called "speculative
insertion". It is an optimistic variant of regular insertion that first
does a pre-check for existing tuples and then attempts an insert. If a
violating tuple was inserted concurrently, the speculatively inserted
tuple is deleted and a new attempt is made. If the pre-check finds a
matching tuple the alternative DO NOTHING or DO UPDATE action is taken.
If the insertion succeeds without detecting a conflict, the tuple is
deemed inserted.
To handle the possible ambiguity between the excluded alias and a table
named excluded, and for convenience with long relation names, INSERT
INTO now can alias its target table.
Bumps catversion as stored rules change.
Author: Peter Geoghegan, with significant contributions from Heikki
Linnakangas and Andres Freund. Testing infrastructure by Jeff Janes.
Reviewed-By: Heikki Linnakangas, Andres Freund, Robert Haas, Simon Riggs,
Dean Rasheed, Stephen Frost and many others.
Previously, relation range table entries used a single Bitmapset field
representing which columns required either UPDATE or INSERT privileges,
despite the fact that INSERT and UPDATE privileges are separately
cataloged, and may be independently held. As statements so far required
either insert or update privileges but never both, that was
sufficient. The required permission could be inferred from the top level
statement run.
The upcoming INSERT ... ON CONFLICT UPDATE feature needs to
independently check for both privileges in one statement though, so that
is not sufficient anymore.
Bumps catversion as stored rules change.
Author: Peter Geoghegan
Reviewed-By: Andres Freund
The minmax opclass was using the wrong support functions when
cross-datatypes queries were run. Instead of trying to fix the
pg_amproc definitions (which apparently is not possible), use the
already correct pg_amop entries instead. This requires jumping through
more hoops (read: extra syscache lookups) to obtain the underlying
functions to execute, but it is necessary for correctness.
Author: Emre Hasegeli, tweaked by Álvaro
Review: Andreas Karlsson
Also change BrinOpcInfo to record each stored type's typecache entry
instead of just the OID. Turns out that the full type cache is
necessary in brin_deform_tuple: the original code used the indexed
type's byval and typlen properties to extract the stored tuple, which is
correct in Minmax; but in other implementations that want to store
something different, that's wrong. The realization that this is a bug
comes from Emre also, but I did not use his patch.
I also adopted Emre's regression test code (with smallish changes),
which is more complete.
This commit adds the following functions:
box(point) -> box
bound_box(box, box) -> box
inet_same_family(inet, inet) -> bool
inet_merge(inet, inet) -> cidr
range_merge(anyrange, anyrange) -> anyrange
The first of these is also used to implement a new assignment cast from
point to box.
These functions are the first part of a base to implement an "inclusion"
operator class for BRIN, for multidimensional data types.
Author: Emre Hasegeli
Reviewed by: Andreas Karlsson
The text search functions that involve parsing raw text into lexemes are
remarkably CPU-intensive, so estimating them at the same cost as most other
built-in functions seems like a mistake; moreover, doing so turns out to
discourage the optimizer from using functional indexes on these functions.
After some debate, we've agreed to raise procost from 1 to 100 for
to_tsvector(), plainto_tsvector(), to_tsquery(), ts_headline(),
ts_match_tt(), and ts_match_tq(), which are all the text search functions
that parse raw text.
Also increase procost for the 2-argument form of ts_rewrite()
(tsquery_rewrite_query); while this function doesn't do text parsing,
it does execute a user-supplied SQL query, so its previous procost of 1 is
clearly a drastic underestimate. It seems reasonable to assign it the same
cost we assign to PL functions by default, so 100 is the number here too.
I did not bother bumping catversion for this change, since it does not
break catalog compatibility with the server executable nor result in
any regression test changes.
Per complaint from Andrew Gierth and subsequent discussion.
Otherwise, if there's another crash, some writes from after the first
crash might make it to disk while writes from before the crash fail
to make it to disk. This could lead to data corruption.
Back-patch to all supported versions.
Abhijit Menon-Sen, reviewed by Andres Freund and slightly revised
by me.
Foreign data wrappers can use this capability for so-called "join
pushdown"; that is, instead of executing two separate foreign scans
and then joining the results locally, they can generate a path which
performs the join on the remote server and then is scanned locally.
This commit does not extend postgres_fdw to take advantage of this
capability; it just provides the infrastructure.
Custom scan providers can use this in a similar way. Previously,
it was only possible for a custom scan provider to scan a single
relation. Now, it can scan an entire join tree, provided of course
that it knows how to produce the same results that the join would
have produced if executed normally.
KaiGai Kohei, reviewed by Shigeru Hanada, Ashutosh Bapat, and me.
ParseCommitRecord() accessed xl_xact_origin directly. But the chunks in
the commit record's data only have 4 byte alignment, whereas
xl_xact_origin's members require 8 byte alignment on some
platforms. Update comments to make not of that and copy the record to
stack local storage before reading.
With help from Stefan Kaltenbrunner in pinning down the buildfarm and
verifying the fix.
This does four basic things. First, it provides convenience routines
to coordinate the startup and shutdown of parallel workers. Second,
it synchronizes various pieces of state (e.g. GUCs, combo CID
mappings, transaction snapshot) from the parallel group leader to the
worker processes. Third, it prohibits various operations that would
result in unsafe changes to that state while parallelism is active.
Finally, it propagates events that would result in an ErrorResponse,
NoticeResponse, or NotifyResponse message being sent to the client
from the parallel workers back to the master, from which they can then
be sent on to the client.
Robert Haas, Amit Kapila, Noah Misch, Rushabh Lathia, Jeevan Chalke.
Suggestions and review from Andres Freund, Heikki Linnakangas, Noah
Misch, Simon Riggs, Euler Taveira, and Jim Nasby.
When implementing a replication solution ontop of logical decoding, two
related problems exist:
* How to safely keep track of replication progress
* How to change replication behavior, based on the origin of a row;
e.g. to avoid loops in bi-directional replication setups
The solution to these problems, as implemented here, consist out of
three parts:
1) 'replication origins', which identify nodes in a replication setup.
2) 'replication progress tracking', which remembers, for each
replication origin, how far replay has progressed in a efficient and
crash safe manner.
3) The ability to filter out changes performed on the behest of a
replication origin during logical decoding; this allows complex
replication topologies. E.g. by filtering all replayed changes out.
Most of this could also be implemented in "userspace", e.g. by inserting
additional rows contain origin information, but that ends up being much
less efficient and more complicated. We don't want to require various
replication solutions to reimplement logic for this independently. The
infrastructure is intended to be generic enough to be reusable.
This infrastructure also replaces the 'nodeid' infrastructure of commit
timestamps. It is intended to provide all the former capabilities,
except that there's only 2^16 different origins; but now they integrate
with logical decoding. Additionally more functionality is accessible via
SQL. Since the commit timestamp infrastructure has also been introduced
in 9.5 (commit 73c986add) changing the API is not a problem.
For now the number of origins for which the replication progress can be
tracked simultaneously is determined by the max_replication_slots
GUC. That GUC is not a perfect match to configure this, but there
doesn't seem to be sufficient reason to introduce a separate new one.
Bumps both catversion and wal page magic.
Author: Andres Freund, with contributions from Petr Jelinek and Craig Ringer
Reviewed-By: Heikki Linnakangas, Petr Jelinek, Robert Haas, Steve Singer
Discussion: 20150216002155.GI15326@awork2.anarazel.de,
20140923182422.GA15776@alap3.anarazel.de,
20131114172632.GE7522@alap2.anarazel.de
The original security barrier view implementation, on which RLS is
built, prevented all non-leakproof functions from being pushed down to
below the view, even when the function was not receiving any data from
the view. This optimization improves on that situation by, instead of
checking strictly for non-leakproof functions, it checks for Vars being
passed to non-leakproof functions and allows functions which do not
accept arguments or whose arguments are not from the current query level
(eg: constants can be particularly useful) to be pushed down.
As discussed, this does mean that a function which is pushed down might
gain some idea that there are rows meeting a certain criteria based on
the number of times the function is called, but this isn't a
particularly new issue and the documentation in rules.sgml already
addressed similar covert-channel risks. That documentation is updated
to reflect that non-leakproof functions may be pushed down now, if
they meet the above-described criteria.
Author: Dean Rasheed, with a bit of rework to make things clearer,
along with comment and documentation updates from me.
This provides a mechanism for specifying conversions between SQL data
types and procedural languages. As examples, there are transforms
for hstore and ltree for PL/Perl and PL/Python.
reviews by Pavel Stěhule and Andres Freund
The RLS capability is built on top of the WITH CHECK OPTION
system which was added for auto-updatable views, however, unlike
WCOs on views (which are mandated by the SQL spec to not fire until
after all other constraints and checks are done), it makes much more
sense for RLS checks to happen earlier than constraint and uniqueness
checks.
This patch reworks the structure which holds the WCOs a bit to be
explicitly either VIEW or RLS checks and the RLS-related checks are
done prior to the constraint and uniqueness checks. This also allows
better error reporting as we are now reporting when a violation is due
to a WITH CHECK OPTION and when it's due to an RLS policy violation,
which was independently noted by Craig Ringer as being confusing.
The documentation is also updated to include a paragraph about when RLS
WITH CHECK handling is performed, as there have been a number of
questions regarding that and the documentation was previously silent on
the matter.
Author: Dean Rasheed, with some kabitzing and comment changes by me.
In prepend_row_security_policies(), defaultDeny was always true, so if
there were any hook policies, the RLS policies on the table would just
get discarded. Fixed to start off with defaultDeny as false and then
properly set later if we detect that only the default deny policy exists
for the internal policies.
The infinite recursion detection in fireRIRrules() didn't properly
manage the activeRIRs list in the case of WCOs, so it would incorrectly
report infinite recusion if the same relation with RLS appeared more
than once in the rtable, for example "UPDATE t ... FROM t ...".
Further, the RLS expansion code in fireRIRrules() was handling RLS in
the main loop through the rtable, which lead to RTEs being visited twice
if they contained sublink subqueries, which
prepend_row_security_policies() attempted to handle by exiting early if
the RTE already had securityQuals. That doesn't work, however, since
if the query involved a security barrier view on top of a table with
RLS, the RTE would already have securityQuals (from the view) by the
time fireRIRrules() was invoked, and so the table's RLS policies would
be ignored. This is fixed in fireRIRrules() by handling RLS in a
separate loop at the end, after dealing with any other sublink
subqueries, thus ensuring that each RTE is only visited once for RLS
expansion.
The inheritance planner code didn't correctly handle non-target
relations with RLS, which would get turned into subqueries during
planning. Thus an update of the form "UPDATE t1 ... FROM t2 ..." where
t1 has inheritance and t2 has RLS quals would fail. Fix by making sure
to copy in and update the securityQuals when they exist for non-target
relations.
process_policies() was adding WCOs to non-target relations, which is
unnecessary, and could lead to a lot of wasted time in the rewriter and
the planner. Fix by only adding WCO policies when working on the result
relation. Also in process_policies, we should be copying the USING
policies to the WITH CHECK policies on a per-policy basis, fix by moving
the copying up into the per-policy loop.
Lastly, as noted by Dean, we were simply adding policies returned by the
hook provided to the list of quals being AND'd, meaning that they would
actually restrict records returned and there was no option to have
internal policies and hook-based policies work together permissively (as
all internal policies currently work). Instead, explicitly add support
for both permissive and restrictive policies by having a hook for each
and combining the results appropriately. To ensure this is all done
correctly, add a new test module (test_rls_hooks) to test the various
combinations of internal, permissive, and restrictive hook policies.
Largely from Dean Rasheed (thanks!):
CAEZATCVmFUfUOwwhnBTcgi6AquyjQ0-1fyKd0T3xBWJvn+xsFA@mail.gmail.com
Author: Dean Rasheed, though I added the new hooks and test module.
Right now it is visible whether a replication slot is active in any
session, but not in which. Adding the active_in column, containing the
pid of the backend having acquired the slot, makes it much easier to
associate pg_replication_slots entries with the corresponding
pg_stat_replication/pg_stat_activity row.
This should have been done from the start, but I (Andres) dropped the
ball there somehow.
Author: Craig Ringer, revised by me Discussion:
CAMsr+YFKgZca5_7_ouaMWxA5PneJC9LNViPzpDHusaPhU9pA7g@mail.gmail.com
Tom Lane
Teodor Sigaev
Simon Riggs
Andres Freund
Robert Haas
Joe Conway
Alvaro Herrera
Dean Rasheed
Noah Misch
Peter Eisentraut
Fujii Masao
Magnus Hagander
Bruce Momjian
Stephen Frost
Kevin Grittner
Heikki Linnakangas
Andrew Dunstan