First, as noted by Itagaki Takahiro, a datum of type JSON doesn't
need to be escaped. Second, ensure that numeric output not in
the form of a legal JSON number is quoted and escaped.
The syntax "\n*", that is a backref with a * quantifier directly applied
to it, has never worked correctly in Spencer's library. This has been an
open bug in the Tcl bug tracker since 2005:
https://sourceforge.net/tracker/index.php?func=detail&aid=1115587&group_id=10894&atid=110894
The core of the problem is in parseqatom(), which first changes "\n*" to
"\n+|" and then applies repeat() to the NFA representing the backref atom.
repeat() thinks that any arc leading into its "rp" argument is part of the
sub-NFA to be repeated. Unfortunately, since parseqatom() already created
the arc that was intended to represent the empty bypass around "\n+", this
arc gets moved too, so that it now leads into the state loop created by
repeat(). Thus, what was supposed to be an "empty" bypass gets turned into
something that represents zero or more repetitions of the NFA representing
the backref atom. In the original example, in place of
^([bc])\1*$
we now have something that acts like
^([bc])(\1+|[bc]*)$
At runtime, the branch involving the actual backref fails, as it's supposed
to, but then the other branch succeeds anyway.
We could no doubt fix this by some rearrangement of the operations in
parseqatom(), but that code is plenty ugly already, and what's more the
whole business of converting "x*" to "x+|" probably needs to go away to fix
another problem I'll mention in a moment. Instead, this patch suppresses
the *-conversion when the target is a simple backref atom, leaving the case
of m == 0 to be handled at runtime. This makes the patch in regcomp.c a
one-liner, at the cost of having to tweak cbrdissect() a little. In the
event I went a bit further than that and rewrote cbrdissect() to check all
the string-length-related conditions before it starts comparing characters.
It seems a bit stupid to possibly iterate through many copies of an
n-character backreference, only to fail at the end because the target
string's length isn't a multiple of n --- we could have found that out
before starting. The existing coding could only be a win if integer
division is hugely expensive compared to character comparison, but I don't
know of any modern machine where that might be true.
This does not fix all the problems with quantified back-references. In
particular, the code is still broken for back-references that appear within
a larger expression that is quantified (so that direct insertion of the
quantification limits into the BACKREF node doesn't apply). I think fixing
that will take some major surgery on the NFA code, specifically introducing
an explicit iteration node type instead of trying to transform iteration
into concatenation of modified regexps.
Back-patch to all supported branches. In HEAD, also add a regression test
case for this. (It may seem a bit silly to create a regression test file
for just one test case; but I'm expecting that we will soon import a whole
bunch of regex regression tests from Tcl, so might as well create the
infrastructure now.)
While this doesn't save a huge amount of runtime, it still seems worth
doing, especially since I realized that the data copying I did in my first
draft was quite unnecessary. In this version, once we have the results
cached, getting them back for re-use is really very cheap.
Also, remove the hard-wired limitation to not consider wctype.h results for
character codes above 255. It turns out that we can't push the limit as
far up as I'd originally hoped, because the regex colormap code is not
efficient enough to cope very well with character classes containing many
thousand letters, which a Unicode locale is entirely capable of producing.
Still, we can push it up to U+7FF (which I chose as the limit of 2-byte
UTF8 characters), which will at least make Eastern Europeans happy pending
a better solution. Thus, this commit resolves the specific complaint in
bug #6457, but not the more general issue that letters of non-western
alphabets are mostly not recognized as matching [[:alpha:]].
Create src/backend/regex/README to hold an implementation overview of
the regex package, and fill it in with some preliminary notes about
the code's DFA/NFA processing and colormap management. Much more to
do there of course.
Also, improve some code comments around the colormap and cvec code.
No functional changes except to add one missing assert.
Some line feeds are added to target lists and from lists to make
them more readable. By default they wrap at 80 columns if possible,
but the wrap column is also selectable - if 0 it wraps after every
item.
Andrew Dunstan, reviewed by Hitoshi Harada.
Sync our regex code with upstream changes since last time we did this,
which was Tcl 8.5.0 (see commit df1e965e12).
There are no functional changes here; the main point is just to lay down
a commit-log marker that somebody has looked at this recently, and to do
what we can to keep the two codebases comparable.
Formerly, we just punted when trying to estimate stats for variables coming
out of sub-queries using DISTINCT, on the grounds that whatever stats we
might have for underlying table columns would be inapplicable. But if the
sub-query has only one DISTINCT column, we can consider its output variable
as being unique, which is useful information all by itself. The scope of
this improvement is pretty narrow, but it costs nearly nothing, so we might
as well do it. Per discussion with Andres Freund.
This patch differs from the draft I submitted yesterday in updating various
comments about vardata.isunique (to reflect its extended meaning) and in
tweaking the interaction with security_barrier views. There does not seem
to be a reason why we can't use this sort of knowledge even when the
sub-query is such a view.
This extends the changes of commit 6252c4f9e2
so that we run the cleanup hook earlier for failure cases as well as
success cases. As before, the point is to avoid an assertion failure from
an Assert I added in commit a874fe7b4c, which
was meant to check that no user-written code can be called during portal
cleanup. This fixes a case reported by Pavan Deolasee in which the Assert
could be triggered during backend exit (see the new regression test case),
and also prevents the possibility that the cleanup hook is run after
portions of the portal's state have already been recycled. That doesn't
really matter in current usage, but it foreseeably could matter in the
future.
Back-patch to 9.1 where the Assert in question was added.
Per recent work by Peter Geoghegan, it's significantly faster to
tuplesort on a single sortkey if ApplySortComparator is inlined into
quicksort rather reached via a function pointer. It's also faster
in general to have a version of quicksort which is specialized for
sorting SortTuple objects rather than objects of arbitrary size and
type. This requires a couple of additional copies of the quicksort
logic, which in this patch are generate using a Perl script. There
might be some benefit in adding further specializations here too,
but thus far it's not clear that those gains are worth their weight
in code footprint.
The hstore and json datatypes both have record-conversion functions that
pay attention to column names in the composite values they're handed.
We used to not worry about inserting correct field names into tuple
descriptors generated at runtime, but given these examples it seems
useful to do so. Observe the nicer-looking results in the regression
tests whose results changed.
catversion bump because there is a subtle change in requirements for stored
rule parsetrees: RowExprs from ROW() constructs now have to include field
names.
Andrew Dunstan and Tom Lane
We don't normally allow quals to be pushed down into a view created
with the security_barrier option, but functions without side effects
are an exception: they're OK. This allows much better performance in
common cases, such as when using an equality operator (that might
even be indexable).
There is an outstanding issue here with the CREATE FUNCTION / ALTER
FUNCTION syntax: there's no way to use ALTER FUNCTION to unset the
leakproof flag. But I'm committing this as-is so that it doesn't
have to be rebased again; we can fix up the grammar in a future
commit.
KaiGai Kohei, with some wordsmithing by me.
If tuples were toasted, heap_multi_insert didn't update the ctid on the
original tuples. This caused a failure if there was an after trigger
(including a foreign key), on the table, and a tuple got toasted.
Per off-list report and test case from Ted Phelps
It's not entirely evident how the logic here relates to the
interval_transform function, so let's clue people in that they need to
check that if the rules change.
These were added to kwlist.h as unreserved keywords in separate patches,
but authors forgot to add them to the corresponding list in gram.y.
Because of that, even though they were supposed to be unreserved keywords,
they could not be used as identifiers. src/tools/check_keywords.pl is your
friend.
If somebody puts a window function in WHERE, we should complain about that
in so many words. The previous coding tended to complain about the window
function's arguments instead, which is likely to be misleading to users who
are unclear on the semantics of window functions; as seen for example in
bug #6440 from Matyas Novak.
Just another example of how "add new code at the end" is frequently a bad
heuristic.
This enables ALTER TABLE to skip table and index rebuilds when the
new type is unconstraint varbit, or when the allowable number of bits
is not decreasing.
Noah Misch, with review and a fix for an OID collision by me.
This enables ALTER TABLE to skip table and index rebuilds when a column
is changed to an unconstrained numeric, or when the scale is unchanged
and the precision does not decrease.
Noah Misch, with a few stylistic changes and a fix for an OID
collision by me.
Sometimes it may be useful to get actual row counts out of EXPLAIN
(ANALYZE) without paying the cost of timing every node entry/exit.
With this patch, you can say EXPLAIN (ANALYZE, TIMING OFF) to get that.
Tomas Vondra, reviewed by Eric Theise, with minor doc changes by me.
If LWLockWaitUntilFree was called before the first LWLockAcquire call, you
would either crash because of access to uninitialized array or account the
acquisition incorrectly. LWLockConditionalAcquire doesn't have this problem
because it doesn't update the lwlock stats.
In practice, this never happens because there is no codepath where you would
call LWLockWaitUntilfree before LWLockAcquire after a new process is
launched. But that's just accidental, there's no guarantee that that's
always going to be true in the future.
Spotted by Jeff Janes.
The postmaster was coded to treat any unexpected exit of the startup
process (i.e., the WAL replay process) as a catastrophic crash, and not try
to restart it. This was OK so long as the startup process could not have
any sibling postmaster children. However, if a hot-standby backend
crashes, we SIGQUIT the startup process along with everything else, and the
resulting exit is hardly "unexpected". Treating it as such meant we failed
to restart a standby server after any child crash at all, not only a crash
of the WAL replay process as intended. Adjust that. Back-patch to 9.0
where hot standby was introduced.
Although we will not even issue an XLOG_TBLSPC_DROP WAL record unless
removal of the tablespace's directories succeeds, that does not guarantee
that the same operation will succeed during WAL replay. Foreseeable
reasons for it to fail include temp files created in the tablespace by Hot
Standby backends, wrong directory permissions on a standby server, etc etc.
The original coding threw ERROR if replay failed to remove the directories,
but that is a serious overreaction. Throwing an error aborts recovery,
and worse means that manual intervention will be needed to get the database
to start again, since otherwise the same error will recur on subsequent
attempts to replay the same WAL record. And the consequence of failing to
remove the directories is only that some probably-small amount of disk
space is wasted, so it hardly seems justified to throw an error.
Accordingly, arrange to report such failures as LOG messages and keep going
when a failure occurs during replay.
Back-patch to 9.0 where Hot Standby was introduced. In principle such
problems can occur in earlier releases, but Hot Standby increases the odds
of trouble significantly. Given the lack of field reports of such issues,
I'm satisfied with patching back as far as the patch applies easily.
Originally, most of this code assumed that no Postgres backends could be
running concurrently with it, and so no locking could be needed. That
assumption fails in Hot Standby. While it's still true that Hot Standby
backends should never change values like nextXid, they can examine them,
and consistency is important in some cases such as when computing a
snapshot. Therefore, prudence requires that WAL replay code obtain the
relevant locks when modifying such variables, even though it can examine
them without taking a lock. We were following that coding rule in some
places but not all. This commit applies the coding rule uniformly to all
updates of ShmemVariableCache and MultiXactState fields; a search of the
replay routines did not find any other cases that seemed to be at risk.
In addition, this commit fixes a longstanding thinko in replay of NEXTOID
and checkpoint records: we tried to advance nextOid only if it was behind
the value in the WAL record, but the comparison would draw the wrong
conclusion if OID wraparound had occurred since the previous value.
Better to just unconditionally assign the new value, since OID assignment
shouldn't be happening during replay anyway.
The additional locking seems to be more in the nature of future-proofing
than fixing any live bug, so I am not going to back-patch it. The NEXTOID
fix will be back-patched separately.
RestoreBkpBlocks was in the habit of zeroing and refilling the target
buffer; which was perfectly safe when the code was written, but is unsafe
during Hot Standby operation. The reason is that we have coding rules
that allow backends to continue accessing a tuple in a heap relation while
holding only a pin on its buffer. Such a backend could see transiently
zeroed data, if WAL replay had occasion to change other data on the page.
This has been shown to be the cause of bug #6425 from Duncan Rance (who
deserves kudos for developing a sufficiently-reproducible test case) as
well as Bridget Frey's re-report of bug #6200. It most likely explains the
original report as well, though we don't yet have confirmation of that.
To fix, change the code so that only bytes that are supposed to change will
change, even transiently. This actually saves cycles in RestoreBkpBlocks,
since it's not writing the same bytes twice.
Also fix seq_redo, which has the same disease, though it has to work a bit
harder to meet the requirement.
So far as I can tell, no other WAL replay routines have this type of bug.
In particular, the index-related replay routines, which would certainly be
broken if they had to meet the same standard, are not at risk because we
do not have coding rules that allow access to an index page when not
holding a buffer lock on it.
Back-patch to 9.0 where Hot Standby was added.
All other WAL redo routines either call RestoreBkpBlocks() or Assert that
they haven't been passed any backup blocks. Make this one do likewise.
Also, fix incorrect routine name in its failure message.
When testing bits (but not when setting or clearing them), we now
won't check whether the map has been extended. This significantly
improves performance in the case where the visibility map doesn't
exist yet, by avoiding an extra system call per tuple. To make
sure backends notice eventually, send an smgr inval on VM extension.
Dean Rasheed, with minor modifications by me.
On some platforms, strtod() reports ERANGE for a denormalized value (ie,
one that can be represented as distinct from zero, but is too small to have
full precision). On others, it doesn't. It seems better to try to accept
these values consistently, so add a test to see if the result value
indicates a true out-of-range condition. This should be okay per Single
Unix Spec. On machines where the underlying math isn't IEEE standard, the
behavior for such small numbers may not be very consistent, but then it
wouldn't be anyway.
Marti Raudsepp, after a proposal by Jeroen Vermeulen
Like the XML data type, we simply store JSON data as text, after checking
that it is valid. More complex operations such as canonicalization and
comparison may come later, but this is enough for not.
There are a few open issues here, such as whether we should attempt to
detect UTF-8 surrogate pairs represented as \uXXXX\uYYYY, but this gets
the basic framework in place.
If there was a wait-until-free process in the head of the wait queue,
followed by an exclusive locker, the exclusive locker was not be woken up
as it should.
The sequence USAGE privilege is sufficiently similar to the SQL
standard that it seems reasonable to show in the information schema.
Also add some compatibility notes about it on the GRANT reference
page.
When a backend needs to flush the WAL, and someone else is already flushing
the WAL, wait until it releases the WALInsertLock and check if we still need
to do the flush or if the other backend already did the work for us, before
acquiring WALInsertLock. This helps group commit, because when the WAL flush
finishes, all the backends that were waiting for it can be woken up in one
go, and the can all concurrently observe that they're done, rather than
waking them up one by one in a cascading fashion.
This is based on a new LWLock function, LWLockWaitUntilFree(), which has
peculiar semantics. If the lock is immediately free, it grabs the lock and
returns true. If it's not free, it waits until it is released, but then
returns false without grabbing the lock. This is used in XLogFlush(), so
that when the lock is acquired, the backend flushes the WAL, but if it's
not, the backend first checks the current flush location before retrying.
Original patch and benchmarking by Peter Geoghegan and Simon Riggs, although
this patch as committed ended up being very different from that.
When default_text_search_config, default_tablespace, or temp_tablespaces
setting is set per-user or per-database, with an "ALTER USER/DATABASE SET
..." statement, don't throw an error if the text search configuration or
tablespace does not exist. In case of text search configuration, even if
it doesn't exist in the current database, it might exist in another
database, where the setting is intended to have its effect. This behavior
is now the same as search_path's.
Tablespaces are cluster-wide, so the same argument doesn't hold for
tablespaces, but there's a problem with pg_dumpall: it dumps "ALTER USER
SET ..." statements before the "CREATE TABLESPACE" statements. Arguably
that's pg_dumpall's fault - it should dump the statements in such an order
that the tablespace is created first and then the "ALTER USER SET
default_tablespace ..." statements after that - but it seems better to be
consistent with search_path and default_text_search_config anyway. Besides,
you could still create a dump that throws an error, by creating the
tablespace, running "ALTER USER SET default_tablespace", then dropping the
tablespace and running pg_dumpall on that.
Backpatch to all supported versions.
btcostestimate() makes an estimate of the number of index tuples that will
be visited based on knowledge of which index clauses can actually bound the
scan within nbtree. However, it forgot to account for partial indexes in
this calculation, with the result that the cost of the index scan could be
significantly overestimated for a partial index. Fix that by merging the
predicate with the abbreviated indexclause list, in the same way as we do
with the full list to estimate how many heap tuples will be visited.
Also, slightly increase the "fudge factor" that's meant to give preference
to smaller indexes over larger ones. While this is applied to all indexes,
it's most important for partial indexes since it can be the only factor
that makes a partial index look cheaper than a similar full index.
Experimentation shows that the existing value is so small as to easily get
swamped by noise such as page-boundary-roundoff behavior. I'm tempted to
kick it up more than this, but will refrain for now.
Per report from Ruben Blanco. These are long-standing issues, but given
the lack of prior complaints I'm not going to risk changing planner
behavior in back branches by back-patching.
In commit 57664ed25e, I made the planner
wrap non-simple-variable outputs of appendrel children (IOW, child SELECTs
of UNION ALL subqueries) inside PlaceHolderVars, in order to solve some
issues with EquivalenceClass processing. However, this means that any
upper-level WHERE clauses mentioning such outputs will now contain
PlaceHolderVars after they're pushed down into the appendrel child,
and that prevents indxpath.c from recognizing that they could be matched
to index expressions. To fix, add explicit stripping of PlaceHolderVars
from index operands, same as we have long done for RelabelType nodes.
Add a regression test covering both this and the plain-UNION case (which
is a totally different code path, but should also be able to do it).
Per bug #6416 from Matteo Beccati. Back-patch to 9.1, same as the
previous change.
Formerly we passed an empty list to each per-child-table invocation of
grouping_planner, and then merged the results into the global list.
However, that fails if there's a CTE attached to the statement, because
create_ctescan_plan uses the list to find the plan referenced by a CTE
reference; so it was unable to find any CTEs attached to the outer UPDATE
or DELETE. But there's no real reason not to use the same list throughout
the process, and doing so is simpler and faster anyway.
Per report from Josh Berkus of "could not find plan for CTE" failures.
Back-patch to 9.1 where we added support for WITH attached to UPDATE or
DELETE. Add some regression test cases, too.
We can't just skip initializing such subplans, because the referencing CTE
node will expect to find the subplan available when it initializes. That
in turn means that ExecInitModifyTable must allow the case (which actually
it needed to do anyway, since there's no guarantee that ModifyTable is
exactly at the top of the CTE plan tree). So move the complaint about not
being allowed in EvalPlanQual mode to execution instead of initialization.
Testing turned up yet another problem, which is that we'd try to
re-initialize the result relation's index list, leading to leaks and
dangling pointers.
Per report from Phil Sorber. Back-patch to 9.1 where data-modifying CTEs
were introduced.
After the planner was fixed to convert some IN/EXISTS subqueries into
semijoins or antijoins, we had to prevent it from doing that in some
cases where the plans risked getting much worse. The reason the plans
got worse was that in the unoptimized implementation, subqueries could
reference parameters from the outer query at any join level, and so
full table scans could be avoided even if they were one or more levels
of join below where the semi/anti join would be. Now that we have
sufficient mechanism in the planner to handle such cases properly,
it should no longer be necessary to play dumb here.
This reverts commits 07b9936a0f and
cd1f0d04bf. The latter was a stopgap
fix that wasn't really sufficiently analyzed at the time. Rather
than just restricting ourselves to cases where the new join can be
stacked on the right-hand input, we should also consider whether it
can be stacked on the left-hand input.
This patch fixes the planner so that it can generate nestloop-with-
inner-indexscan plans even with one or more levels of joining between
the indexscan and the nestloop join that is supplying the parameter.
The executor was fixed to handle such cases some time ago, but the
planner was not ready. This should improve our plans in many situations
where join ordering restrictions formerly forced complete table scans.
There is probably a fair amount of tuning work yet to be done, because
of various heuristics that have been added to limit the number of
parameterized paths considered. However, we are not going to find out
what needs to be adjusted until the code gets some real-world use, so
it's time to get it in there where it can be tested easily.
Note API change for index AM amcostestimate functions. I'm not aware of
any non-core index AMs, but if there are any, they will need minor
adjustments.
Hitherto, the information schema only showed explicitly granted
privileges that were visible in the *acl catalog columns. If no
privileges had been granted, the implicit privileges were not shown.
To fix that, add an SQL-accessible version of the acldefault()
function, and use that inside the aclexplode() calls to substitute the
catalog-specific default privilege set for null values.
reviewed by Abhijit Menon-Sen
In e5e2fc842c, blank lines were removed
after a comment block, which now looks as though the comment refers to
the immediately following code, but it actually refers to the
preceding code. So put the blank lines back.
This has been the behavior already in most cases, but through
omission, ALTER DOMAIN / OWNER TO and ALTER DOMAIN / SET SCHEMA would
silently work on non-domain types as well.
Those fields only appear in the structs so that genbki.pl can create
the BKI bootstrap files for the catalogs. But they are not actually
usable from C. So hiding them can prevent coding mistakes, saves
stack space, and can help the compiler.
In certain catalogs, the first variable-length field has been kept
visible after manual inspection. These exceptions are noted in C
comments.
reviewed by Tom Lane
Normally, accessing variable-length members of catalog structures past
the first one doesn't work at all. Here, it happened to work because
indnatts was checked to be 1, and so the defined FormData_pg_index
layout, using int2vector[1] and oidvector[1] for variable-length
arrays, happened to match the actual memory layout. But it's a very
fragile assumption, and it's not in a performance-critical path, so
code it properly using heap_getattr() instead.
bug analysis by Tom Lane
Our own qsort_arg() implementation doesn't have the defect previously
observed to affect only QNX 4, so it seems sufficiently to assert that
it isn't broken rather than retesting. Also, update a few comments to
clarify why it's valuable to retain a tie-break rule based on CTID
during index builds.
Peter Geoghegan, with slight tweaks by me.
We now use the same error message for ALTER TABLE .. ADD COLUMN or
ALTER TABLE .. RENAME COLUMN that we do for CREATE TABLE. The old
message was accurate, but might be confusing to users not aware of our
system columns.
Vik Reykja, with some changes by me, and further proofreading by Tom Lane
To make it wake up promptly when activity starts again, backends nudge it
by setting a latch in MarkBufferDirty(). The latch is kept set while
bgwriter is active, so there is very little overhead from that when the
system is busy. It is only armed before going into longer sleep.
Peter Geoghegan, with some changes by me.
This doesn't do anything useful just yet, but is intended as supporting
infrastructure for allowing sepgsql to sensibly check DROP permissions.
KaiGai Kohei and Robert Haas
Add counters for number and size of temporary files used
for spill-to-disk queries for each database to the
pg_stat_database view.
Tomas Vondra, review by Magnus Hagander
Rip out a regression test that doesn't play well with settings put in
place by the build farm, and rewrite the code in CheckIndexCompatible
in a hopefully more transparent style.
This gives up the "don't rewrite the index" behavior in a couple of
relatively unimportant cases, such as changing between an array type
and an unconstrained domain over that array type, in return for
making this code more future-proof.
Noah Misch
Base backup follows recommended procedure, plus goes to great
lengths to ensure that partial page writes are avoided.
Jun Ishizuka and Fujii Masao, with minor modifications
This reports the depth level of triggers currently in execution, or zero
if not called from inside a trigger.
No catversion bump in this patch, but you have to initdb if you want
access to the new function.
Author: Kevin Grittner
Replication occurs only to memory on standby, not to disk,
so provides additional performance if user wishes to
reduce durability level slightly. Adds concept of multiple
independent sync rep queues.
Fujii Masao and Simon Riggs
We log AccessExclusiveLocks for replay onto standby nodes,
but because of timing issues on ProcArray it is possible to
log a lock that is still held by a just committed transaction
that is very soon to be removed. To avoid any timing issue we
avoid applying locks made by transactions with InvalidXid.
Simon Riggs, bug report Tom Lane, diagnosis Pavan Deolasee
This separates the state (running/idle/idleintransaction etc) into
it's own field ("state"), and leaves the query field containing just
query text.
The query text will now mean "current query" when a query is running
and "last query" in other states. Accordingly,the field has been
renamed from current_query to query.
Since backwards compatibility was broken anyway to make that, the procpid
field has also been renamed to pid - along with the same field in
pg_stat_replication for consistency.
Scott Mead and Magnus Hagander, review work from Greg Smith
That avoids errors when the functions are used in queries like "SELECT
pg_relation_size(oid) FROM pg_class", and a table is dropped concurrently.
Phil Sorber
When the only remaining active transactions are READ ONLY, we do a "partial
cleanup" of committed transactions because certain types of conflicts
aren't possible anymore. For committed r/w transactions, we release the
SIREAD locks but keep the SERIALIZABLEXACT. However, for committed r/o
transactions, we can go further and release the SERIALIZABLEXACT too. The
problem was with the latter case: we were returning the SERIALIZABLEXACT to
the free list without removing it from the finished list.
The only real change in the patch is the SHMQueueDelete line, but I also
reworked some of the surrounding code to make it obvious that r/o and r/w
transactions are handled differently -- the existing code felt a bit too
clever.
Dan Ports
This prevents the postmaster from unexpectedly croaking if postgresql.conf
contains something like:
include 'invalid_directory_name'
Noah Misch. Reviewed by Tom Lane and myself.
When creating a child table, or when attaching an existing table as
child of another, we must not allow inheritable constraints to be
merged with non-inheritable ones, because then grandchildren would not
properly get the constraint. This would violate the grandparent's
expectations.
Bugs noted by Robert Haas.
Author: Nikhil Sontakke
In the previous coding, it was possible for a relation to be created
via CREATE TABLE, CREATE VIEW, CREATE SEQUENCE, CREATE FOREIGN TABLE,
etc. in a schema while that schema was meanwhile being concurrently
dropped. This led to a pg_class entry with an invalid relnamespace
value. The same problem could occur if a relation was moved using
ALTER .. SET SCHEMA while the target schema was being concurrently
dropped. This patch prevents both of those scenarios by locking the
schema to which the relation is being added using AccessShareLock,
which conflicts with the AccessExclusiveLock taken by DROP.
As a desirable side effect, this also prevents the use of CREATE OR
REPLACE VIEW to queue for an AccessExclusiveLock on a relation on which
you have no rights: that will now fail immediately with a permissions
error, before trying to obtain a lock.
We need similar protection for all other object types, but as everything
other than relations uses a slightly different set of code paths, I'm
leaving that for a separate commit.
Original complaint (as far as I could find) about CREATE by Nikhil
Sontakke; risk for ALTER .. SET SCHEMA pointed out by Tom Lane;
further details by Dan Farina; patch by me; review by Hitoshi Harada.
When the remote end of the pipe is closed, select() reports the fd as
readable, but poll() has a separate POLLHUP return code for that.
Spotted by Peter Geoghegan.
Allows a user to use pg_cancel_queries() to cancel queries in
other backends if they are running under the same role.
pg_terminate_backend() still requires superuser permissoins.
Short patch, many authors working on the bikeshed: Magnus Hagander,
Josh Kupershmidt, Edward Muller, Greg Smith.
superuser doesn't have doesn't make much sense, as a superuser can do
whatever he wants through other means, anyway. So instead of granting
replication privilege to superusers in CREATE USER time by default, allow
replication connection from superusers whether or not they have the
replication privilege.
Patch by Noah Misch, per discussion on bug report #6264
As noted by Tom Lane, the previous coding in this area, which I
introduced in commit bbb6e559c4, was
poorly tested and caused the vacuum's second heap to go into what would
have been an infinite loop but for the fact that it eventually caused a
memory allocation failure. This version seems to work better.
Previously we used ReadRecPtr rather than EndRecPtr, which was
not a serious error but caused pg_stat_replication to report
incorrect replay_location until at least one WAL record is replayed.
Fujii Masao
In commit 7b0d0e9356, I made CLUSTER and
VACUUM FULL try to preserve toast value OIDs from the original toast table
to the new one. However, if we have to copy both live and recently-dead
versions of a row that has a toasted column, those versions may well
reference the same toast value with the same OID. The patch then led to
duplicate-key failures as we tried to insert the toast value twice with the
same OID. (The previous behavior was not very desirable either, since it
would have silently inserted the same value twice with different OIDs.
That wastes space, but what's worse is that the toast values inserted for
already-dead heap rows would not be reclaimed by subsequent ordinary
VACUUMs, since they go into the new toast table marked live not deleted.)
To fix, check if the copied OID already exists in the new toast table, and
if so, assume that it stores the desired value. This is reasonably safe
since the only case where we will copy an OID from a previous toast pointer
is when toast_insert_or_update was given that toast pointer and so we just
pulled the data from the old table; if we got two different values that way
then we have big problems anyway. We do have to assume that no other
backend is inserting items into the new toast table concurrently, but
that's surely safe for CLUSTER and VACUUM FULL.
Per bug #6393 from Maxim Boguk. Back-patch to 9.0, same as the previous
patch.
constructed before acquiring WALInsertLock, which slightly reduces the time
the lock is held. Although I could not measure any benefit in benchmarks,
the code is more readable this way.
Andrew Dunstan
Tom Lane
Robert Haas
Heikki Linnakangas
Peter Eisentraut
Simon Riggs
Magnus Hagander
Alvaro Herrera
Bruce Momjian