HandleFunctionRequest() is no longer responsible for reading the protocol
message from the client, since commit 2b3a8b20c2. Fix the outdated
comments.
HandleFunctionRequest() now always returns 0, because the code that used
to return EOF was moved in 2b3a8b20c2. Therefore, the caller no longer
needs to check the return value.
Reported by Andres Freund. Backpatch to all supported versions, even though
this doesn't have any user-visible effect, to make backporting future
patches in this area easier.
Discussion: https://www.postgresql.org/message-id/20170405010525.rt5azbya5fkbhvrx@alap3.anarazel.de
When using integer timestamps, the interval-comparison functions tried
to compute the overall magnitude of an interval as an int64 number of
microseconds. As reported by Frazer McLean, this overflows for intervals
exceeding about 296000 years, which is bad since we nominally allow
intervals many times larger than that. That results in wrong comparison
results, and possibly in corrupted btree indexes for columns containing
such large interval values.
To fix, compute the magnitude as int128 instead. Although some compilers
have native support for int128 calculations, many don't, so create our
own support functions that can do 128-bit addition and multiplication
if the compiler support isn't there. These support functions are designed
with an eye to allowing the int128 code paths in numeric.c to be rewritten
for use on all platforms, although this patch doesn't do that, or even
provide all the int128 primitives that will be needed for it.
Back-patch as far as 9.4. Earlier releases did not guard against overflow
of interval values at all (commit 146604ec4 fixed that), so it seems not
very exciting to worry about overly-large intervals for them.
Before 9.6, we did not assume that unreferenced "static inline" functions
would not draw compiler warnings, so omit functions not directly referenced
by timestamp.c, the only present consumer of int128.h. (We could have
omitted these functions in HEAD too, but since they were written and
debugged on the way to the present patch, and they look likely to be needed
by numeric.c, let's keep them in HEAD.) I did not bother to try to prevent
such warnings in a --disable-integer-datetimes build, though.
Before 9.5, configure will never define HAVE_INT128, so the part of
int128.h that exploits a native int128 implementation is dead code in the
9.4 branch. I didn't bother to remove it, thinking that keeping the file
looking similar in different branches is more useful.
In HEAD only, add a simple test harness for int128.h in src/tools/.
In back branches, this does not change the float-timestamps code path.
That's not subject to the same kind of overflow risk, since it computes
the interval magnitude as float8. (No doubt, when this code was originally
written, overflow was disregarded for exactly that reason.) There is a
precision hazard instead :-(, but we'll avert our eyes from that question,
since no complaints have been reported and that code's deprecated anyway.
Kyotaro Horiguchi and Tom Lane
Discussion: https://postgr.es/m/1490104629.422698.918452336.26FA96B7@webmail.messagingengine.com
This backpatches 51e26c9 and 7220c7b, including both documentation
updates clarifying the checkpoints at the beginning of base backups and
the messages in verbose and progress mdoe of pg_basebackup.
Author: Michael Banck
Discussion: https://postgr.es/m/21444.1488142764%40sss.pgh.pa.us
Commit 45be99f8cd5d606086e0a458c9c72910ba8a613d removed GatherPath's
num_workers field, but this is entirely bogus. Normally, a path's
parallel_workers flag is supposed to indicate the number of workers
that it wants, and should be 0 for a non-partial path. In that
commit, I mistakenly thought that GatherPath could also use that field
to indicate the number of workers that it would try to start, but
that's disastrous, because then it can propagate up to higher nodes in
the plan tree, which will then get incorrect rowcounts because the
parallel_workers flag is involved in computing those values. Repair
by putting the separate field back.
Report by Tomas Vondra. Patch by me, reviewed by Amit Kapila.
Discussion: http://postgr.es/m/f91b4a44-f739-04bd-c4b6-f135bd643669@2ndquadrant.com
On EXEC_BACKEND builds, this can fail if ASLR is in use.
Backpatch to 9.5. On master, completely remove the bgw_main field
completely, since there is no situation in which it is safe for an
EXEC_BACKEND build. On 9.6 and 9.5, leave the field intact to avoid
breaking things for third-party code that doesn't care about working
under EXEC_BACKEND. Prior to 9.5, there are no in-core bgworker
entrypoints.
Petr Jelinek, reviewed by me.
Discussion: http://postgr.es/m/09d8ad33-4287-a09b-a77f-77f8761adb5e@2ndquadrant.com
Previously a detailed activity report by VACUUM VERBOSE ANALYZE was
described as an example of VACUUM in docs. But it had been obsolete
for a long time. For example, commit feb4f44d296b88b7f0723f4a4f3945a371276e0b
updated the content of that activity report in 2003, but we had
forgotten to update the example.
So basically we need to update the example. But since no one cared
about the details of VACUUM output and complained about that mistake
for such long time, per discussion on hackers, we decided to get rid
of the detailed activity report from the example and simplify it.
Back-patch to all supported versions.
Reported by Masahiko Sawada, patch by me.
Discussion: https://postgr.es/m/CAD21AoAGA2pB3p-CWmTkxBsbkZS1bcDGBLcYVcvcDxspG_XAfA@mail.gmail.com
We were assigning values near 255 through "char *" pointers. On machines
where char is signed, that's not entirely kosher, and it's reasonable
for compilers to warn about it.
A better solution would be to change the pointer type to "unsigned char *",
but that would be vastly more invasive. For the moment, let's just apply
this simple backpatchable solution.
Aleksander Alekseev
Discussion: https://postgr.es/m/20170220141239.GD12278@e733.localdomain
Discussion: https://postgr.es/m/2839.1490714708@sss.pgh.pa.us
The compiler is entitled to store a char[] local variable with no
particular alignment requirement. Our RADIUS code cavalierly took such
a local variable and cast its address to a struct type that does have
alignment requirements. On an alignment-picky machine this would lead
to bus errors. To fix, declare the local variable honestly, and then
cast its address to char * for use in the I/O calls.
Given the lack of field complaints, there must be very few if any
people affected; but nonetheless this is a clear portability issue,
so back-patch to all supported branches.
Noted while looking at a Coverity complaint in the same code.
Commit 7aea8e4f2daa4b39ca9d1309a0c4aadb0f7ed81b allowed a parallel
plan to be generated when for a RETURN QUERY or RETURN QUERY EXECUTE
statement in a PL/pgsql block, but that's a bad idea because plplgsql
asks the executor for 50 rows at a time. That means that we'll always
be running serially a plan that was intended for parallel execution,
which is not a good idea. Fix by not requesting a parallel plan from
the outset.
Per discussion, back-patch to 9.6. There is a slight risk that, due
to optimizer error, somebody could have a case where the parallel plan
executed serially is actually faster than the supposedly-best serial
plan, but the consensus seems to be that that's not sufficient
justification for leaving 9.6 unpatched.
Discussion: http://postgr.es/m/CA+TgmoZ_ZuH+auEeeWnmtorPsgc_SmP+XWbDsJ+cWvWBSjNwDQ@mail.gmail.com
Discussion: http://postgr.es/m/CA+TgmobXEhvHbJtWDuPZM9bVSLiTj-kShxQJ2uM5GPDze9fRYA@mail.gmail.com
The bug is that prior to --rate doCustom was always disconnect/reconnect
without exiting, but with rate it returns if it has to wait. However threadRun
test whether there is a connection before recalling doCustom, so it was never
called.
Bug is not existed in head branch because of refactoring at
12788ae49e1933f463bc59a6efe46c4a01701b76, patch only 9.6
Author: Fabien Coelho
Reviewed-by: me
https://commitfest.postgresql.org/13/970/
Assert-enabled build crashes but without asserts it works by wrong way:
it may not reset forcing full page write and preventing from starting
exclusive backup with the same name as cancelled.
Patch replaces pair of booleans
nonexclusive_backup_running/exclusive_backup_running to single enum to
correctly describe backup state.
Backpatch to 9.6 where bug was introduced
Reported-by: David Steele
Authors: Michael Paquier, David Steele
Reviewed-by: Anastasia Lubennikova
https://commitfest.postgresql.org/13/1068/
This reverts commit 38bdba54a64bacec78e3266f0848b0b4a824132a, "Fix and
simplify check for whether we're running as Windows service". It turns out
that older versions of MinGW - like that on buildfarm member narwhal - do
not support the CheckTokenMembership() function. This replaces the
refactoring with a much smaller fix, to add a check for SE_GROUP_ENABLED to
pgwin32_is_service().
Only apply to back-branches, and keep the refactoring in HEAD. It's
unlikely that anyone is still really using such an old version of MinGW -
aside from narwhal - but let's not change the minimum requirements in
minor releases.
Discussion: https://www.postgresql.org/message-id/16609.1489773427@sss.pgh.pa.us
Patch: https://www.postgresql.org/message-id/CAB7nPqSvfu%3DKpJ%3DNX%2BYAHmgAmQdzA7N5h31BjzXeMgczhGCC%2BQ%40mail.gmail.com
of SP-GiST.
Bug exists since initial commit of box opclass for SP-GiST,
so backpath to 9.6
Author: Nikita Glukhov with minor editorization of tests by me
Reviewed-by: Kyotaro Horiguchi, Anastasia Lubennikova
https://commitfest.postgresql.org/13/981/
this makes buffer access strategy have no effect.
Change was a part of commit 48354581a49c30f5757c203415aa8412d85b0f70 during 9.6
release cycle, so backpath to 9.6
Reported-by: Jim Nasby
Author: Alexander Korotkov
Reviewed-by: Jim Nasby, Andres Freund
https://commitfest.postgresql.org/13/1029/
Windows apparently will not detect socket write-ready events unless a
preceding send attempt returned WSAEWOULDBLOCK. In many usage patterns
that's satisfied by the caller of WaitEvenSetWait(), but not always.
Apply the same solution that we already had in pgwin32_select(), namely to
perform a dummy WSASend() call with len=0. This will return WSAEWOULDBLOCK
if there's no buffer space (even though it could legitimately do nothing
and report success, which makes me a bit nervous about this solution;
but since it's been working fine in libpq, let's roll with it).
In passing, improve the comments about this in pgwin32_select(), and remove
duplicated code there.
Back-patch to 9.6 where WaitEventSetWait() was introduced. We might need
to back-patch something similar into predecessor code. But given the lack
of complaints so far, it's not clear that the case ever gets exercised
in the back branches, so I'm not going to expend effort on it right now.
This should resolve recurring failures on buildfarm member bowerbird,
which has been failing since 1e8a85009 went in.
Diagnosis and patch by Petr Jelinek, cosmetic adjustments by me.
Discussion: https://postgr.es/m/5b6a6d6d-fb45-0afb-2e95-5600063c3dbd@2ndquadrant.com
Concurrent auto-analyze could be holding a snapshot, affecting the
removal of deleted row versions. Remove the deletion to avoid this
happening. Per buildfarm.
In passing, make the test independent of assumptions of physical row
order, just out of sheer paranoia.
If the process token contains SECURITY_SERVICE_RID, but it has been
disabled by the SE_GROUP_USE_FOR_DENY_ONLY attribute, win32_is_service()
would incorrectly report that we're running as a service. That situation
arises, e.g. if postmaster is launched with a restricted security token,
with the "Log in as Service" privilege explicitly removed.
Replace the broken code with CheckProcessTokenMembership(), which does
this correctly. Also replace similar code in win32_is_admin(), even
though it got this right, for simplicity and consistency.
Per bug #13755, reported by Breen Hagan. Back-patch to all supported
versions. Patch by Takayuki Tsunakawa, reviewed by Michael Paquier.
Discussion: https://www.postgresql.org/message-id/20151104062315.2745.67143%40wrigleys.postgresql.org
presence of page pins, which leads to serious estimation errors in the
planner. This particularly affects small heavily-accessed tables,
especially where locking (e.g. from FK constraints) forces frequent
vacuums for mxid cleanup.
Fix by keeping separate track of pages whose live tuples were actually
counted vs. pages that were only scanned for freezing purposes. Thus,
reltuples can only be set to 0 if all pages of the relation were
actually counted.
Backpatch to all supported versions.
Per bug #14057 from Nicolas Baccelli, analyzed by me.
Discussion: https://postgr.es/m/20160331103739.8956.94469@wrigleys.postgresql.org
The original coding was trying to use a TypeName as a string Value,
which doesn't work; an oversight in my commit a61fd533. Repair.
Also, make sure we cover the broken case in the relevant test script.
Backpatch to 9.5.
Discussion: https://postgr.es/m/20170315151829.bhxsvrp75xdxhm3n@alvherre.pgsql
This could result in corruption of the init fork of an unlogged index
if the ambuildempty routine for that index used shared buffers to
create the init fork, which was true for brin, gin, gist, and hash
indexes.
Patch by me, based on an earlier patch by Michael Paquier, who also
reviewed this one. This also incorporates an idea from Artur
Zakirov.
Discussion: http://postgr.es/m/CACYUyc8yccE4xfxhqxfh_Mh38j7dRFuxfaK1p6dSNAEUakxUyQ@mail.gmail.com
Rather than waiting around for statement_timeout to expire, we can just
try to take the table's lock in nowait mode. This saves some fraction
under 4 seconds when running this test with prepared xacts available,
and it guards against timeout-expired-anyway failures on very slow
machines when prepared xacts are not available, as seen in a recent
failure on axolotl for instance.
This approach could fail if autovacuum were to take an exclusive lock
on the test table concurrently, but there's no reason for it to do so.
Since the main point here is to improve stability in the buildfarm,
back-patch to all supported branches.
The problem was that "begin transaction" was issued automatically
before executing COMMIT/ROLLBACK PREPARED if not in auto commit. This fix by
Masahiko Sawada fixes this.
Detect fclose() failures; given "ln -s /dev/full $PGDATA/devfull",
"pg_file_write('devfull', 'x', true)" now fails as it should. Don't
leak a stream when fwrite() fails. Remove a born-ineffective test that
aimed to skip zero-length writes. Back-patch to 9.2 (all supported
versions).
Commits 89e0bac86 et al replaced newlines with spaces in object names
printed in SQL comments, but we neglected to consider that the same
names are also printed by "pg_restore -l", and a newline would render
the output unparseable by "pg_restore -L". Apply the same replacement
in "-l" output. Since "pg_restore -L" doesn't actually examine any
object names, only the dump ID field that starts each line, this is
enough to fix things for its purposes.
The previous fix was treated as a security issue, and we might have
done that here as well, except that the issue was reported publicly
to start with. Anyway it's hard to see how this could be exploited
for SQL injection; "pg_restore -L" doesn't do much with the file
except parse it for leading integers.
Per bug #14587 from Milos Urbanek. Back-patch to all supported versions.
Discussion: https://postgr.es/m/20170310155318.1425.30483@wrigleys.postgresql.org
The IANA timezone crew continues to chip away at their project of removing
timezone abbreviations that have no real-world currency from their
database. The tzdata2017a update removes all such abbreviations for
South American zones, as well as much of the Pacific. This breaks some
test cases in timestamptz.sql that were expecting America/Santiago and
America/Caracas to have non-numeric abbreviations.
The test cases involving America/Santiago seem to have selected that
zone more or less at random, so just replace it with America/New_York,
which is of similar longitude. The cases involving America/Caracas are
harder since they were chosen to test a time-varying zone abbreviation
around a point where it changed meaning in the backwards direction.
Fortunately, Europe/Moscow has a similar case in 2014, and the MSK/MSD
abbreviations are well enough attested that IANA seems unlikely to
decide to remove them from the database in future.
With these changes, this regression test should pass when using any IANA
zone database from 2015 or later. One could wish that there were a few
years more daylight on how out-of-date your zone database can be ... but
really the --with-system-tzdata option is only meant for use on platforms
where the zone database is kept up-to-date pretty faithfully, so I do not
think this is a big objection.
Discussion: https://postgr.es/m/6749.1489087470@sss.pgh.pa.us
Large chunks (those too large for any palloc freelist) are managed as
separate blocks. Formerly, realloc'ing or pfree'ing such a chunk required
O(N) time in a context with N blocks, since we had to traipse down the
singly-linked block list to locate the block's predecessor before we could
fix the list links. This can result in O(N^2) runtime in situations where
large numbers of such chunks are manipulated within one context. Cases
like that were not foreseen in the original design of aset.c, and indeed
didn't arise until fairly recently. But such problems can now occur in
reorderbuffer.c and in hash joining, both of which make repeated large
requests without scaling up their request size as they do so, and which
will free their requests in not-necessarily-LIFO order.
To fix, change the block list from singly-linked to doubly-linked.
This adds another 4 or 8 bytes to ALLOC_BLOCKHDRSZ, but that doesn't
seem like unacceptable overhead, since aset.c's blocks are normally
8K or more, and never less than 1K in current practice.
In passing, get rid of some redundant AllocChunkGetPointer() calls in
AllocSetRealloc (the compiler might be smart enough to optimize these
away anyway, but no need to assume that) and improve AllocSetCheck's
checking of block header fields.
Back-patch to 9.4 where reorderbuffer.c appeared. We could take this
further back, but currently there's no evidence that it would be useful.
Discussion: https://postgr.es/m/CAMkU=1x1hvue1XYrZoWk_omG0Ja5nBvTdvgrOeVkkeqs71CV8g@mail.gmail.com
Not only did it not accept --builtin as a synonym for -b, but what it did
accept as a synonym was --tpc-b (huh?), which it got even further wrong
by marking as no_argument, so that if you did try that you got a core
dump. I suppose this is leftover from some early design for the new
switches added by commit 8bea3d221, but it's still pretty sloppy work.
Per bug #14580 from Stepan Pesternikov. Back-patch to 9.6 where the
error was introduced.
Report: https://postgr.es/m/20170307123347.25054.73207@wrigleys.postgresql.org
pg_dump has always handled the public schema in a special way when it
comes to the "--clean" option. To wit, we do not drop or recreate the
public schema in "normal" mode, but when we are run in "--clean" mode
then we do drop and recreate the public schema.
When running in "--clean" mode, the public schema is dropped and then
recreated and it is recreated with the normal schema-default privileges
of "nothing". This is unlike how the public schema starts life, which
is to have CREATE and USAGE GRANT'd to the PUBLIC role, and that is what
is recorded in pg_init_privs.
Due to this, in "--clean" mode, pg_dump would mistakenly only dump out
the set of privileges required to go from the initdb-time privileges on
the public schema to whatever the current-state privileges are. If the
privileges were not changed from initdb time, then no privileges would
be dumped out for the public schema, but with the schema being dropped
and recreated, the result was that the public schema would have no ACLs
on it instead of what it should have, which is the initdb-time
privileges.
Practically speaking, this meant that pg_dump with --clean mode dumping
a database where the ACLs on the public schema were not changed from the
default would, upon restore, result in a public schema with *no*
privileges GRANT'd, not matching the state of the existing database
(where the initdb-time privileges would have been CREATE and USAGE to
the PUBLIC role for the public schema).
To fix, adjust the query in getNamespaces() to ignore the pg_init_privs
entry for the public schema when running in "--clean" mode, meaning that
the privileges for the public schema would be dumped, correctly, as if
it was going from a newly-created schema to the current state (which is,
indeed, what will happen during the restore thanks to the DROP/CREATE).
Only the public schema is handled in this special way by pg_dump, no
other initdb-time objects are dropped/recreated in --clean mode.
Back-patch to 9.6 where the bug was introduced.
Discussion: https://postgr.es/m/3534542.o3cNaKiDID%40techfox
We attached no schema label to comments for procedural languages, casts,
transforms, operator classes, operator families, or text search objects.
The first three categories of objects don't really have schemas, but
pg_dump treats them as if they do, and it seems like the TocEntry fields
for their comments had better match the TocEntry fields for the parent
objects. (As an example of a possible hazard, the type names in a CAST
will be formatted with the assumption of a particular search_path, so
failing to ensure that this same path is active for the COMMENT ON command
could lead to an error or to attaching the comment to the wrong cast.)
In the last six cases, this was a flat-out error --- possibly mine to
begin with, but it was a long time ago.
The security label for a procedural language was likewise not correctly
labeled as to schema, and both the comment and security label for a
procedural language were not correctly labeled as to owner.
In simple cases the restore would accidentally work correctly anyway, since
these comments and security labels would normally get emitted right after
the owning object, and so the search path and active user would be correct
anyhow. But it could fail in corner cases; for example a schema-selective
restore would omit comments it should include.
Giuseppe Broccolo noted the oversight, and proposed the correct fix, for
text search dictionary objects; I found the rest by cross-checking other
dumpComment() calls. These oversights are ancient, so back-patch all
the way.
Discussion: https://postgr.es/m/CAFzmHiWwwzLjzwM4x5ki5s_PDMR6NrkipZkjNnO3B0xEpBgJaA@mail.gmail.com
When performing a pg_upgrade, we copy the files behind pg_largeobject
and pg_largeobject_metadata, allowing us to avoid having to dump out and
reload the actual data for large objects and their ACLs.
Unfortunately, that isn't all of the information which can be associated
with large objects. Currently, we also support COMMENTs and SECURITY
LABELs with large objects and these were being silently dropped during a
pg_upgrade as pg_dump would skip everything having to do with a large
object and pg_upgrade only copied the tables mentioned to the new
cluster.
As the file copies happen after the catalog dump and reload, we can't
simply include the COMMENTs and SECURITY LABELs in pg_dump's binary-mode
output but we also have to include the actual large object definition as
well. With the definition, comments, and security labels in the pg_dump
output and the file copies performed by pg_upgrade, all of the data and
metadata associated with large objects is able to be successfully pulled
forward across a pg_upgrade.
In 9.6 and master, we can simply adjust the dump bitmask to indicate
which components we don't want. In 9.5 and earlier, we have to put
explciit checks in in dumpBlob() and dumpBlobs() to not include the ACL
or the data when in binary-upgrade mode.
Adjustments made to the privileges regression test to allow another test
(large_object.sql) to be added which explicitly leaves a large object
with a comment in place to provide coverage of that case with
pg_upgrade.
Back-patch to all supported branches.
Discussion: https://postgr.es/m/20170221162655.GE9812@tamriel.snowman.net
With RLS active, "COPY tab TO ..." failed under -DRELCACHE_FORCE_RELEASE,
and would sometimes fail without that, because it used the relation name
directly from the relcache as part of the parsetree it's building. That
becomes a potentially-dangling pointer as soon as the relcache entry is
closed, a bit further down. Typical symptom if the relcache entry chanced
to get cleared would be "relation does not exist" error with a garbage
relation name, or possibly a core dump; but if you were really truly
unlucky, the COPY might copy from the wrong table.
Per report from Andrew Dunstan that regression tests fail with
-DRELCACHE_FORCE_RELEASE. The core tests now pass for me (but have
not tried "make check-world" yet).
Discussion: https://postgr.es/m/7b52f900-0579-cda9-ae2e-de5da17090e6@2ndQuadrant.com
This reliably fails with -DRELCACHE_FORCE_RELEASE, as reported by
Andrew Dunstan, and could sometimes fail in normal operation, resulting
in a wrong persistence value being used for the transient table.
It's not immediately clear to me what effects that might have beyond
the risk of a crash while accessing OldHeap->rd_rel->relpersistence,
but it's probably not good.
Bug introduced by commit f41872d0c, and made substantially worse by
commit 85b506bbf, which added a second such access significantly
later than the heap_close. I doubt the first reference could fail
in a production scenario, but the second one definitely could.
Discussion: https://postgr.es/m/7b52f900-0579-cda9-ae2e-de5da17090e6@2ndQuadrant.com
Likewise in RestoreSnapshot(). Do so by copying between the user buffer
and a stack buffer of known alignment. Back-patch to 9.6, where this
last applies cleanly. In master, the select_parallel test dies with
SIGBUS on "Oracle Solaris 10 1/13 s10s_u11wos_24a SPARC", building
32-bit with gcc 4.9.2. In 9.6 and 9.5, the buffers in question happen
to be sufficiently-aligned, and this change is mere insurance against
future 9.6 changes or extension code compromising that.
Newer Perl or IPC::Run versions default to appending the filename to string
exceptions, e.g. the exception
psql timed out
is thrown as
psql timed out at /usr/share/perl5/vendor_perl/IPC/Run.pm line 2961.
To handle this, match exceptions with !~ rather than ne.
From: Craig Ringer <craig@2ndquadrant.com>
Reviewed-by: Dagfinn Ilmari Mannsåker <ilmari@ilmari.org>
Previously the pg_upgrade standby upgrade instructions said not to
execute pgcrypto.sql, but it should have referenced the extension
command "CREATE EXTENSION pgcrypto". This patch makes that doc change.
Reported-by: a private bug report
Backpatch-through: 9.4, where standby instructions were added
We have a portable way of writing uint64 constants, but whoever wrote
this macro didn't know about it.
While at it, fix unsafe under-parenthesization of arguments. That might
be moot, because there are already good reasons not to use the macro on
anything more complicated than a simple variable, but it's still poor
practice.
Per buildfarm warnings.
The logic for removing excess trigrams from the result was faulty.
It intends to avoid merging the initial and final states of the NFA,
which is necessary, but in testing whether removal of a specific trigram
would cause that, it failed to consider the combined effects of all the
state merges that that trigram's removal would cause. This could result
in a broken final graph that would never match anything, leading to GIN
or GiST indexscans not finding anything.
To fix, add a "tentParent" field that is used only within this loop,
and set it to show state merges that we are tentatively going to do.
While examining a particular arc, we must chase up through tentParent
links as well as regular parent links (the former can only appear atop
the latter), and we must account for state init/fin flag merges that
haven't actually been done yet.
To simplify the latter, combine the separate init and fin bool fields
into a bitmap flags field. I also chose to get rid of the "children"
state list, which seems entirely inessential.
Per bug #14563 from Alexey Isayko, which the added test cases are based on.
Back-patch to 9.3 where this code was added.
Report: https://postgr.es/m/20170222111446.1256.67547@wrigleys.postgresql.org
Discussion: https://postgr.es/m/8816.1487787594@sss.pgh.pa.us
Walsender uses the local buffers for each outgoing and incoming message.
Previously when creating replication slot, walsender forgot to initialize
one of them and which can cause the segmentation fault error. To fix this
issue, this commit changes walsender so that it always initialize them
before it executes the requested replication command.
Back-patch to 9.4 where replication slot was introduced.
Problem report and initial patch by Stas Kelvich, modified by me.
Report: https://www.postgresql.org/message-id/A1E9CB90-1FAC-4CAD-8DBA-9AA62A6E97C5@postgrespro.ru
Several places in fd.c had badly-thought-through handling of error returns
from lseek() and close(). The fact that those would seldom fail on valid
FDs is probably the reason we've not noticed this up to now; but if they
did fail, we'd get quite confused.
LruDelete and LruInsert actually just Assert'd that lseek never fails,
which is pretty awful on its face.
In LruDelete, we indeed can't throw an error, because that's likely to get
called during error abort and so throwing an error would probably just lead
to an infinite loop. But by the same token, throwing an error from the
close() right after that was ill-advised, not to mention that it would've
left the LRU state corrupted since we'd already unlinked the VFD from the
list. I also noticed that really, most of the time, we should know the
current seek position and it shouldn't be necessary to do an lseek here at
all. As patched, if we don't have a seek position and an lseek attempt
doesn't give us one, we'll close the file but then subsequent re-open
attempts will fail (except in the somewhat-unlikely case that a
FileSeek(SEEK_SET) call comes between and allows us to re-establish a known
target seek position). This isn't great but it won't result in any state
corruption.
Meanwhile, having an Assert instead of an honest test in LruInsert is
really dangerous: if that lseek failed, a subsequent read or write would
read or write from the start of the file, not where the caller expected,
leading to data corruption.
In both LruDelete and FileClose, if close() fails, just LOG that and mark
the VFD closed anyway. Possibly leaking an FD is preferable to getting
into an infinite loop or corrupting the VFD list. Besides, as far as I can
tell from the POSIX spec, it's unspecified whether or not the file has been
closed, so treating it as still open could be the wrong thing anyhow.
I also fixed a number of other places that were being sloppy about
behaving correctly when the seekPos is unknown.
Also, I changed FileSeek to return -1 with EINVAL for the cases where it
detects a bad offset, rather than throwing a hard elog(ERROR). It seemed
pretty inconsistent that some bad-offset cases would get a failure return
while others got elog(ERROR). It was missing an offset validity check for
the SEEK_CUR case on a closed file, too.
Back-patch to all supported branches, since all this code is fundamentally
identical in all of them.
Discussion: https://postgr.es/m/2982.1487617365@sss.pgh.pa.us
