Use GUC variable pg_trgm.similarity_threshold insead of
set_limit()/show_limit() which was introduced when defining GUC varuables
by modules was absent.
Author: Artur Zakirov
There's a lot more that could be done here yet - in particular, this
reports only very coarse-grained information about the index vacuuming
phase - but even as it stands, the new pg_stat_progress_vacuum can
tell you quite a bit about what a long-running vacuum is actually
doing.
Amit Langote and Robert Haas, based on earlier work by Vinayak Pokale
and Rahila Syed.
This is basically like the just-added create_upper_paths_hook, but
control is funneled only to the FDW responsible for all the baserels
of the current query; so providing such a callback is much less likely
to add useless overhead than using the hook function is.
The documentation is a bit sketchy. We'll likely want to improve it,
and/or adjust the call conventions, when we get some experience with
actually using this callback. Hopefully somebody will find time to
experiment with it before 9.6 feature freeze.
In commit 19a541143a I did not make PathTarget a subtype of Node,
and embedded a RelOptInfo's reltarget directly into it rather than having
a separately-allocated Node. In hindsight that was misguided
micro-optimization, enabled by the fact that at that point we didn't have
any Paths with custom PathTargets. Now that PathTarget processing has
been fleshed out some more, it's easier to see that it's better to have
PathTarget as an indepedent Node type, even if it does cost us one more
palloc to create a RelOptInfo. So change it while we still can.
This commit just changes the representation, without doing anything more
interesting than that.
Commit e2609323e set the minimum Tcl version we support to 8.4, but
I forgot to adjust the documentation to say the same. Some nosing
around for other consequences found that the configure script could
be simplified slightly as well.
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
It is frequently useful for volatile, set-returning, or expensive functions
in a SELECT's targetlist to be postponed till after ORDER BY and LIMIT are
done. Otherwise, the functions might be executed for every row of the
table despite the presence of LIMIT, and/or be executed in an unexpected
order. For example, in
SELECT x, nextval('seq') FROM tab ORDER BY x LIMIT 10;
it's probably desirable that the nextval() values are ordered the same
as x, and that nextval() is not run more than 10 times.
In the past, Postgres was inconsistent in this area: you would get the
desirable behavior if the ordering were performed via an indexscan, but
not if it had to be done by an explicit sort step. Getting the desired
behavior reliably required contortions like
SELECT x, nextval('seq')
FROM (SELECT x FROM tab ORDER BY x) ss LIMIT 10;
This patch conditionally postpones evaluation of pure-output target
expressions (that is, those that are not used as DISTINCT, ORDER BY, or
GROUP BY columns) so that they effectively occur after sorting, even if an
explicit sort step is necessary. Volatile expressions and set-returning
expressions are always postponed, so as to provide consistent semantics.
Expensive expressions (costing more than 10 times typical operator cost,
which by default would include any user-defined function) are postponed
if there is a LIMIT or if there are expressions that must be postponed.
We could be more aggressive and postpone any nontrivial expression, but
there are costs associated with doing so: it requires an extra Result plan
node which adds some overhead, and postponement changes the volume of data
going through the sort step, perhaps for the worse. Since we tend not to
have very good estimates of the output width of nontrivial expressions,
it's hard to have much confidence in our ability to predict whether
postponement would increase or decrease the cost of the sort; therefore
this patch doesn't attempt to make decisions conditionally on that.
Between these factors and a general desire not to change query behavior
when there's not a demonstrable benefit, it seems best to be conservative
about applying postponement. We might tweak the decision rules in the
future, though.
Konstantin Knizhnik, heavily rewritten by me
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
New configuration parameter auto_explain.sample_ratio makes it
possible to log just a fraction of the queries meeting the configured
threshold, to reduce the amount of logging.
Author: Craig Ringer and Julien Rouhaud
Review: Petr Jelinek
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
Commit a892234f83 gave us enough
infrastructure to avoid vacuuming pages where every tuple on the
page is already frozen. So, replace the notion of a scan_all or
whole-table vacuum with the less onerous notion of an "aggressive"
vacuum, which will pages that are all-visible, but still skip those
that are all-frozen.
This should greatly reduce the cost of anti-wraparound vacuuming
on large clusters where the majority of data is never touched
between one cycle and the next, because we'll no longer have to
read all of those pages only to find out that we don't need to
do anything with them.
Patch by me, reviewed by Masahiko Sawada.
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.
The chapter "Interfacing Extensions To Indexes" and CREATE OPERATOR
CLASS reference page were missed when BRIN was added. We document
all our other index access methods there, so make sure BRIN complies.
Author: Álvaro Herrera
Reported-By: Julien Rouhaud, Tom Lane
Reviewed-By: Emre Hasegeli
Discussion: https://www.postgresql.org/message-id/56CF604E.9000303%40dalibo.com
Backpatch: 9.5, where BRIN was introduced
The pg_resetxlog reference page didn't have a proper options list, only
running text listing the options and some explanations of them. This
might have worked when there were only a few options, but the list has
grown over the releases, and now it's hard to find an option and its
associated explanation. So write out the options list as on other
reference pages.
pgcrypto already supports key-stretching during symmetric encryption,
including the salted-and-iterated method; but the number of iterations
was not configurable. This commit implements a new s2k-count parameter
to pgp_sym_encrypt() which permits selecting a larger number of
iterations.
Author: Jeff Janes
This lets you examine the visibility map as well as page-level
visibility information. I initially wrote it as a debugging aid,
but was encouraged to polish it for commit.
Patch by me, reviewed by Masahiko Sawada.
Discussion: 56D77803.6080503@BlueTreble.com
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.
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.
Previously recovery_min_apply_delay was applied even before recovery
had reached consistency. This could cause us to wait a long time
unexpectedly for read-only connections to be allowed. It's problematic
because the standby was useless during that wait time.
This patch changes recovery_min_apply_delay so that it's applied once
the database has reached the consistent state. That is, even if the delay
is set, the standby tries to replay WAL records as fast as possible until
it has reached consistency.
Author: Michael Paquier
Reviewed-By: Julien Rouhaud
Reported-By: Greg Clough
Backpatch: 9.4, where recovery_min_apply_delay was added
Bug: #13770
Discussion: http://www.postgresql.org/message-id/20151111155006.2644.84564@wrigleys.postgresql.org
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
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.
Fabien Coelho, reviewed mostly by Michael Paquier and me, but also by
Heikki Linnakangas, BeomYong Lee, Kyotaro Horiguchi, Oleksander
Shulgin, and Álvaro Herrera.
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.
The "Session Information Functions" table seems to be sorted mostly
alphabetically (although it's not perfect), which would be all right
if it didn't lead to some related functions being described in a
pretty nonintuitive order. Also, the prose discussions after the table
were in an order that hardly matched the table at all. Rearrange to
make things a bit easier to follow.
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
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.
Dead or half-dead index leaf pages were incorrectly reported as live, as a
consequence of a code rearrangement I made (during a moment of severe brain
fade, evidently) in commit d287818eb5.
The index metapage was not counted in index_size, causing that result to
not agree with the actual index size on-disk.
Index root pages were not counted in internal_pages, which is inconsistent
compared to the case of a root that's also a leaf (one-page index), where
the root would be counted in leaf_pages. Aside from that inconsistency,
this could lead to additional transient discrepancies between the reported
page counts and index_size, since it's possible for pgstatindex's scan to
see zero or multiple pages marked as BTP_ROOT, if the root moves due to
a split during the scan. With these fixes, index_size will always be
exactly one page more than the sum of the displayed page counts.
Also, the index_size result was incorrectly documented as being measured in
pages; it's always been measured in bytes. (While fixing that, I couldn't
resist doing some small additional wordsmithing on the pgstattuple docs.)
Including the metapage causes the reported index_size to not be zero for
an empty index. To preserve the desired property that the pgstattuple
regression test results are platform-independent (ie, BLCKSZ configuration
independent), scale the index_size result in the regression tests.
The documentation issue was reported by Otsuka Kenji, and the inconsistent
root page counting by Peter Geoghegan; the other problems noted by me.
Back-patch to all supported branches, because this has been broken for
a long time.
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.
Clarify the description of which transactions will block a CREATE INDEX
CONCURRENTLY command from proceeding, and mention that the index might
still not be usable after CREATE INDEX completes. (This happens if the
index build detected broken HOT chains, so that pg_index.indcheckxmin gets
set, and there are open old transactions preventing the xmin horizon from
advancing past the index's initial creation. I didn't want to explain what
broken HOT chains are, though, so I omitted an explanation of exactly when
old transactions prevent the index from being used.)
Per discussion with Chris Travers. Back-patch to all supported branches,
since the same text appears in all of them.
In runtime.sgml, the old formulas for calculating the reasonable
values of SEMMNI and SEMMNS were incorrect. They have forgotten to
count the number of semaphores which both the checkpointer process
(introduced in 9.2) and the background worker processes (introduced
in 9.3) need.
This commit fixes those formulas so that they count the number of
semaphores which the checkpointer process and the background worker
processes need.
Report and patch by Kyotaro Horiguchi. Only the patch for 9.3 was
modified by me. Back-patch to 9.2 where the checkpointer process was
added and the number of needed semaphores was increased.
Author: Kyotaro Horiguchi
Reviewed-by: Fujii Masao
Backpatch: 9.2
Discussion: http://www.postgresql.org/message-id/20160203.125119.66820697.horiguchi.kyotaro@lab.ntt.co.jp
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
Many automated test suites call pg_ctl. Buildfarm members axolotl,
hornet, mandrill, shearwater, sungazer and tern have failed when server
shutdown took longer than the pg_ctl default 60s timeout. This addition
permits slow hosts to easily raise the timeout without us editing a
--timeout argument into every test suite pg_ctl call. Back-patch to 9.1
(all supported versions) for the sake of automated testing.
Reviewed by Tom Lane.
If we've got a relatively straightforward join between two tables,
this pushes that join down to the remote server instead of fetching
the rows for each table and performing the join locally. Some cases
are not handled yet, such as SEMI and ANTI joins. Also, we don't
yet attempt to create presorted join paths or parameterized join
paths even though these options do get tried for a base relation
scan. Nevertheless, this seems likely to be a very significant win
in many practical cases.
Shigeru Hanada and Ashutosh Bapat, reviewed by Robert Haas, with
additional review at various points by Tom Lane, Etsuro Fujita,
KaiGai Kohei, and Jeevan Chalke.
Get rid of the false implication that PRIMARY KEY is exactly equivalent to
UNIQUE + NOT NULL. That was more-or-less true at one time in our
implementation, but the standard doesn't say that, and we've grown various
features (many of them required by spec) that treat a pkey differently from
less-formal constraints. Per recent discussion on pgsql-general.
I failed to resist the temptation to do some other wordsmithing in the
same area.
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.
Commit a104a017fc has this check because
I added it to the submitted patch before commit, but that was entirely
wrongheaded, as explained to me by Ashutosh Bapat, who also wrote this
patch.
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
Since there currently is only one possible parenthesized option, namely
VERBOSE, it's a bit pointless to show it with "{ } [, ... ]". The curly
braces are useless and therefore confusing, as seen in a recent question
from Karsten Hilbert. Remove the extra decoration for the time being;
we can put it back when and if REINDEX grows some more options.
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.
The default fetch size of 100 rows might not be right in every
environment, so allow users to configure it.
Corey Huinker, reviewed by Kyotaro Horiguchi, Andres Freund, and me.
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>
Provide per-script statistical info (count of transactions executed
under that script, average latency for the whole script) after a
multi-script run, adding an intermediate level of detail to existing
global stats and per-command stats.
Author: Fabien Coelho
Reviewer: Michaël Paquier, Álvaro Herrera
The documentation mentioned contrib/ but the module was moved to
src/test/modules/ by commit 22dfd116a1 of 9.5 era.
Problem pointed out by Dickson Guedes in bug #13896
Backpatch-to: 9.5.
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
Previously, it was possible to specify one or several custom scripts to
run, or only one of the builtin scripts. With this patch it is also
possible to specify to run the builtin scripts multiple times, using the
new -b option. Also, unify the code for both cases; this eases future
pgbench improvements.
Author: Fabien Coelho
Review: Michaël Paquier, Álvaro Herrera
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
Historically, extract() just returned zero for any case involving an
infinite timestamp[tz] input; even cases in which the unit name was
invalid. This is not very sensible. Instead, return infinity or
-infinity as appropriate when the requested field is one that is
monotonically increasing (e.g, year, epoch), or NULL when it is not
(e.g., day, hour). Also, throw the expected errors for bad unit names.
BACKWARDS INCOMPATIBLE CHANGE
Vitaly Burovoy, reviewed by Vik Fearing
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.
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
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
Commit 43cd468cf0 added some wording to create_policy.sgml purporting
to warn users against a race condition of the sort that had been noted some
time ago by Peter Geoghegan. However, that warning was far too vague to be
useful (or at least, I completely failed to grasp what it was on about).
Since the problem case occurs with a security design pattern that lots of
people are likely to try to use, we need to be as clear as possible about
it. Provide a concrete example in the main-line docs in place of the
original warning.
Some time back we agreed that row_security=off should not be a way to
bypass RLS entirely, but only a way to get an error if it was being
applied. However, the code failed to act that way for table owners.
Per discussion, this is a must-fix bug for 9.5.0.
Adjust the logic in rls.c to behave as expected; also, modify the
error message to be more consistent with the new interpretation.
The regression tests need minor corrections as well. Also update
the comments about row_security in ddl.sgml to be correct. (The
official description of the GUC in config.sgml is already correct.)
I failed to resist the temptation to do some other very minor
cleanup as well, such as getting rid of a duplicate extern declaration.
As pointed out by Michael Paquier, recovery_min_apply_delay didn't exist
in 9.0-9.3, making the release note text not very useful. Instead make it
talk about recovery_target_xid, which did exist then.
9.0 is already out of support, but we can fix the text in the newer
branches' copies of its release notes.
Empty ulink elements default to displaying the URL, so there is no need
to specify the URL again. This was already done for most occurrences,
but some cases didn't follow this convention.
Improve markup, particularly of the table of functions; add or improve
examples for some of the functions; wordsmith some of the function
descriptions.
Commit 33bd250f6c could have done with
some more review:
Adjust coding so that compilers unfamiliar with elog/ereport don't complain
about uninitialized values.
Fix misuse of PG_GETARG_INT16 to retrieve arguments declared as "integer"
at the SQL level. (This was evidently copied from cube_ll_coord and
cube_ur_coord, but those were wrong too.)
Fix non-style-guide-conforming error messages.
Fix underparenthesized if statements, which pgindent would have made a
hash of, and remove some unnecessary parens elsewhere.
Run pgindent over new code.
Revise documentation: repeated accretion of more operators without any
rethinking of the text already there had left things in a bit of a mess.
Merge all the cube operators into one table and adjust surrounding text
appropriately.
David Rowley and Tom Lane
Common mathematical convention is that exponentiation associates right to
left. We aren't going to change the parser for this, but we could note
it in the operator's description. (It's already noted in the operator
precedence/associativity table, but users might not look there.)
Per bug #13829 from Henrik Pauli.
Tone down an overly strong statement about which pseudo-types PLs are
likely to allow. Add "event_trigger" to the list, as well as
"pg_ddl_command" in 9.5/HEAD. Back-patch to 9.3 where event_trigger
was added.
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
Per a recommendation from Tomas Vondra, it's more helpful to refer to
the value that determines how skewed a Gaussian or exponential
distribution is as a parameter rather than a threshold.
Since it's not quite too late to get this right in 9.5, where it was
introduced, back-patch this. Most of the patch changes only comments
and documentation, but a few pgbench messages are altered to match.
Fabien Coelho, reviewed by Michael Paquier and by me.
Introduce distance operators over cubes:
<#> taxicab distance
<-> euclidean distance
<=> chebyshev distance
Also add kNN support of those distances in GiST opclass.
Author: Stas Kelvich
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.
Clarify that SELECT policies are now applied when SELECT rights
are required for a given query, even if the query is an UPDATE or
DELETE query. Pointed out by Noah.
Additionally, note the risk regarding concurrently open transactions
where a relation which controls access to the rows of another relation
are updated and the rows of the primary relation are also being
modified. Pointed out by Peter Geoghegan.
Back-patch to 9.5.
This has worked that way for a long time, maybe always, but you would
not have known it from the documentation. Also back-patch the notes
I added to HEAD earlier today about behavior of the "-f -" switch,
which likewise have been valid for many releases.
Commit d5563d7df9 drew complaints from Coverity, which quite
correctly complained that one copy of each -c or -f string was being
leaked. What's more, simple_action_list_append was allocating enough space
for still a third copy of each string as part of the SimpleActionListCell,
even though that coding method had been superseded by a separate strdup
operation. There were some other minor coding infelicities too. The
documentation needed more work as well, eg it forgot to explain that -c
causes psql not to accept any interactive input.
To support this, we must reconcile some historical anomalies in the
behavior of -c. In particular, as a backward-incompatibility, -c no
longer implies --no-psqlrc.
Pavel Stehule (code) and Catalin Iacob (documentation). Review by
Michael Paquier and myself. Proposed behavior per Tom Lane.
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.
Commit d04c8ed904 added another support function to the GIST API,
but overlooked mentioning it in xindex.sgml's summary of index support
functions.
Anastasia Lubennikova
In commit 1ea0c73c2 I added a section to user-manag.sgml about how to drop
roles that own objects; but as pointed out by Stephen Frost, I neglected
that shared objects (databases or tablespaces) may need special treatment.
Fix that. Back-patch to supported versions, like the previous patch.
Allow pg_rewind to work when target timeline was switched. Now
user can return promoted standby to old master.
Target timeline history becomes a global variable. Index
in target timeline history is used in function interfaces instead of
specifying TLI directly. Thus, SimpleXLogPageRead() can easily start
reading XLOGs from next timeline when current timeline ends.
Author: Alexander Korotkov
Review: Michael Paquier
Previously, if no host information had been specified at connection time,
PQhost() would return NULL (unless you are on Windows, in which case you
got "localhost"). This is an unhelpful definition for a couple of reasons:
it can cause corner-case crashes in applications (cf commit c5ef8ce53d),
and there's no well-defined way for applications to find out the socket
directory path that's actually in use. As an example of the latter
problem, psql substituted DEFAULT_PGSOCKET_DIR for NULL in a couple of
places, but this is subtly wrong because it's conceivable that psql is
using a libpq shared library that was built with a different setting.
Hence, change PQhost() to return DEFAULT_PGSOCKET_DIR when appropriate,
and strip out the now-dead substitutions in psql. (There is still one
remaining reference to DEFAULT_PGSOCKET_DIR in psql, in prompt.c, which
I don't see a nice way to get rid of. But it only controls a prompt
abbreviation decision, so it seems noncritical.)
Also update the docs for PQhost, which had never previously mentioned
the possibility of a socket directory path being returned. In passing
fix the outright-incorrect code comment about PGconn.pgunixsocket.
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 sepgsql docs included a comment that PG doesn't support RLS. That
is only true for versions prior to 9.5.
Update the docs for 9.5 and master to say that PG supports RLS but that
sepgsql does not yet.
Pointed out by Heikki.
Back-patch to 9.5
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.
Also fill in the previously empty "major enhancements" list. YMMV as to
which items should make the cut, but it's past time we had something more
than a placeholder here.
(I meant to get this done before beta2 was wrapped, but got distracted by
PDF build problems. Better late than never.)
These were discussed in three different sections of the manual, which
unsurprisingly had diverged over time; and the descriptions of individual
variables lacked stylistic consistency even within each section (and
frequently weren't in very good English anyway). Clean up the mess, and
remove some of the redundant information in hopes that future additions
will be less likely to re-introduce inconsistency. For instance I see
no need for maintenance.sgml to include its very own list of all the
autovacuum storage parameters, especially since that list was already
incomplete.
Commit 8457d0beca introduced an example which, while not incorrect,
failed to exhibit the behavior it meant to describe, as a result of omitting
an E'' prefix that needed to be there. Noticed and fixed by Peter Geoghegan.
I (tgl) failed to resist the temptation to wordsmith nearby text a bit
while at it.
Robert Haas
Teodor Sigaev
Tom Lane
Magnus Hagander
Andres Freund
Alvaro Herrera
Simon Riggs
Peter Eisentraut
Joe Conway
Fujii Masao
Tatsuo Ishii
Dean Rasheed
Bruce Momjian
Noah Misch
Andrew Dunstan
Stephen Frost