According to the SQL standard, if the referential action RESTRICT is
triggered, it has its own error code. We previously didn't use that,
we just used the error code for foreign key violation. But RESTRICT
is not necessarily an actual foreign key violation. The foreign key
might still be satisfied in theory afterwards, but the RESTRICT
setting prevents the action even then. So it's a separate kind of
error condition.
Discussion: https://www.postgresql.org/message-id/ea5b2777-266a-46fa-852f-6fca6ec480ad@eisentraut.org
The loops over cursor argument variables neglected to ever advance
"prevvar". The code would accidentally do the right thing anyway
when removing the first or second list entry, but if it had to
remove the third or later entry then it would also remove all
entries between there and the first entry. AFAICS this would
only matter for cursors that reference out-of-scope variables,
which is a weird Informix compatibility hack; between that and
the lack of impact for short lists, it's not so surprising that
nobody has complained. Nonetheless it's a pretty obvious bug.
It would have been more obvious if these loops used a more standard
coding style for chasing the linked lists --- this business with the
"prev" pointer sometimes pointing at the current list entry is
confusing and overcomplicated. So rather than just add a minimal
band-aid, I chose to rewrite the loops in the same style we use
elsewhere, where the "prev" pointer is NULL until we are dealing with
a non-first entry and we save the "next" pointer at the top of the
loop. (Two of the four loops touched here are not actually buggy,
but it seems better to make them all look alike.)
Coverity discovered this problem, but not until 2b41de4a5 added code
to free no-longer-needed arguments structs. With that, the incorrect
link updates are possibly touching freed memory, and it complained
about that. Nonetheless the list corruption hazard is ancient, so
back-patch to all supported branches.
As I'd feared, commit 5c9d8636d was still a few bricks shy of a load.
We can't just leave pulled-up lateral-reference Vars with no new
nullingrels: we have to carefully compute what subset of the
to-be-replaced Var's nullingrels apply to them, else we still get
"wrong varnullingrels" errors. This is a bit tedious, but it looks
like we can use the nullingrel data this patch computes for other
purposes, enabling better optimization. We don't want to inject
unnecessary plan changes into stable branches though, so leave that
idea for a later HEAD-only patch.
Patch by me, but thanks to Richard Guo for devising a test case that
broke 5c9d8636d, and for preliminary investigation about how to fix
it. As before, back-patch to v16.
Discussion: https://postgr.es/m/E1tGn4j-0003zi-MP@gemulon.postgresql.org
Some lines were indented by an inconsistent number of spaces. While
we're here, also fix some code that used the newline after left
parenthesis style, which is obsolete.
Some of the behaviors of the different referential actions, such as
the difference between NO ACTION and RESTRICT are best illustrated
using a case-insensitive collation. So add some tests for that.
(What is actually being tested here is the behavior with values that
are "distinct" (binary different) but compare as equal. Another way
to do that would be with positive and negative zeroes with float
types. But this way seems nicer and more flexible.)
Discussion: https://www.postgresql.org/message-id/ea5b2777-266a-46fa-852f-6fca6ec480ad@eisentraut.org
There is no point in transforming OR-clauses into SAOP's if the target index
doesn't support SAOP scans anyway. This commit adds corresponding checks
to match_orclause_to_indexcol() and group_similar_or_args(). The first check
fixes the actual bug, while the second just saves some cycles.
Reported-by: Alexander Lakhin
Discussion: https://postgr.es/m/8174de69-9e1a-0827-0e81-ef97f56a5939%40gmail.com
Author: Alena Rybakina
Reviewed-by: Ranier Vilela, Alexander Korotkov, Andrei Lepikhov
Like 91f5a4a000 for pg_amcheck, this makes the code more
self-documented as there is less need to look in the headers what a
hardcoded value means. This touches queries related to procedures, AMs,
functions, databases, relations, constraints, collations, types and
extended stats, pulling into psql their *_d.h headers. The queries are
written the same way as originally.
There are still a couple of hardcoded values. These cannot be included
yet as they are not exposed in headers that are safe to use in frontend
code.
Note that describe.c was including pg_am.h that should be used only in
backend code. This is updated to use pg_am_d.h.
Reviewed-by: Daniel Gustafsson, Corey Huinker
Discussion: https://postgr.es/m/Zxb2hpca-pZc6zKe@paquier.xyz
If we are pulling up a subquery that's under an outer join, and
the subquery's target list contains a strict expression that uses
both a subquery variable and a lateral-reference variable, it's okay
to pull up the expression without wrapping it in a PlaceHolderVar.
That's safe because if the subquery variable is forced to NULL
by the outer join, the expression result will come out as NULL too,
so we don't have to force that outcome by evaluating the expression
below the outer join. It'd be correct to wrap in a PHV, but that can
lead to very significantly worse plans, since we'd then have to use
a nestloop plan to pass down the lateral reference to where the
expression will be evaluated.
However, when we do that, we should not mark the lateral reference
variable as being nulled by the outer join, because it isn't after
we pull up the expression in this way. So the marking logic added
by cb8e50a4a was incorrect in this detail, leading to "wrong
varnullingrels" errors from the consistency-checking logic in
setrefs.c. It seems to be sufficient to just not mark lateral
references at all in this case. (I have a nagging feeling that more
complexity may be needed in cases where there are several levels of
outer join, but some attempts to break it with that didn't succeed.)
Per report from Bertrand Mamasam. Back-patch to v16, as the previous
patch was.
Discussion: https://postgr.es/m/CACZ67_UA_EVrqiFXJu9XK50baEpH=ofEPJswa2kFxg6xuSw-ww@mail.gmail.com
The C standard says that sizeof(bool) is implementation-defined, but we
know of no current systems where it is not 1. The last known systems
seem to have been Apple macOS/PowerPC 10.5 and Microsoft Visual C++ 4,
both long defunct.
PostgreSQL has always required sizeof(bool) == 1 for the definition of
bool that it used, but previously it would define its own type if the
system-provided bool had a different size. That was liable to cause
memory layout problems when interacting with system and third-party
libraries on (by now hypothetical) computers with wider _Bool, and now
C23 has introduced a new problem by making bool a built-in datatype
(like C++), so the fallback code doesn't even compile. We could
probably work around that, but then we'd be writing new untested code
for a computer that doesn't exist.
Instead, delete the unreachable and C23-uncompilable fallback code, and
let existing static assertions fail if the system-provided bool is too
wide. If we ever get a problem report from a real system, then it will
be time to figure out what to do about it in a way that also works on
modern compilers.
Note on C++: Previously we avoided including <stdbool.h> or trying to
define a new bool type in headers that might be included by C++ code.
These days we might as well just include <stdbool.h> unconditionally:
it should be visible to C++11 but do nothing, just as in C23. We
already include <stdint.h> without C++ guards in c.h, and that falls
under the same C99-compatibility section of the C++11 standard as
<stdbool.h>, so let's remove the guards here too.
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/3198438.1731895163%40sss.pgh.pa.us
Presently, we check for compiler support for the required
intrinsics both with and without the -msse4.2 compiler flag, and
then depending on the results of those checks, we pick which files
to compile with which flags. This is tedious and complicated, and
it results in unsustainable coding patterns such as separate files
for each portion of code that may need to be built with different
compiler flags.
This commit makes use of the newly-added support for
__attribute__((target(...))) in the SSE4.2 CRC-32C code. This
simplifies both the configure-time checks and the build scripts,
and it allows us to place the functions that use the intrinsics in
files that we otherwise do not want to build with special CPU
instructions (although this commit refrains from doing so). This
is also preparatory work for a proposed follow-up commit that will
further optimize the CRC-32C code with AVX-512 instructions.
While at it, this commit modifies meson's checks for SSE4.2 CRC
support to be the same as autoconf's. meson was choosing whether
to use a runtime check based purely on whether -msse4.2 is
required, while autoconf has long checked for the __SSE4_2__
preprocessor symbol to decide. meson's previous approach seems to
work just fine, but this change avoids needing to build multiple
test programs and to keep track of whether to actually use
pg_attribute_target().
Ideally we'd use __attribute__((target(...))) for ARMv8 CRC
support, too, but there's little point in doing so because until
clang 16, using the ARM intrinsics still requires special compiler
flags. Perhaps we can re-evaluate this decision after some time
has passed.
Author: Raghuveer Devulapalli
Discussion: https://postgr.es/m/PH8PR11MB8286BE735A463468415D46B5FB5C2%40PH8PR11MB8286.namprd11.prod.outlook.com
They were all missing punctuation, one was missing initial capital.
Per our message style guidelines.
No backpatch, to avoid breaking existing translations.
Avoid leaking the prior value when updating the "connection"
state variable.
Ditto for ECPGstruct_sizeof. (It seems like this one ought to
be statement-local, but testing says it isn't, and I didn't
feel like diving deeper.)
The actual_type[] entries are statement-local, though, so
no need to mm_strdup() strings stored in them.
Likewise, sqlda variables are statement-local, so we can
loc_alloc them.
Also clean up sloppiness around management of the argsinsert and
argsresult lists.
progname changes are strictly to prevent valgrind from complaining
about leaked allocations.
With this, valgrind reports zero leakage in the ecpg preprocessor
for all of our ecpg regression test cases.
Discussion: https://postgr.es/m/2011420.1713493114@sss.pgh.pa.us
This didn't work earlier in the patch series (I think some of
the strings were ending up in data-type-related structures),
but apparently we're now clean enough for it. This considerably
reduces process-lifespan memory leakage.
Discussion: https://postgr.es/m/2011420.1713493114@sss.pgh.pa.us
ECPGfree_type() and related functions were quite incomplete
about removing subsidiary data structures. Possibly this is
because ecpg wasn't careful to make sure said data structures
always had their own storage. Previous patches in this series
cleaned up a lot of that, and I had to add a couple more
mm_strdup's here.
Also, ecpg.trailer tended to overwrite struct_member_list[struct_level]
without bothering to free up its previous contents, thus potentially
leaking a lot of struct-member-related storage. Add
ECPGfree_struct_member() calls at appropriate points.
Discussion: https://postgr.es/m/2011420.1713493114@sss.pgh.pa.us
Commit 0785d1b8b adds support for libpq as a JSON client, but
allocations for string tokens can still be leaked during parsing
failures. This is tricky to fix for the object_field semantic callbacks:
the field name must remain valid until the end of the object, but if a
parsing error is encountered partway through, object_field_end() won't
be invoked and the client won't get a chance to free the field name.
This patch adds a flag to switch the ownership of parsed tokens to the
lexer. When this is enabled, the client must make a copy of any tokens
it wants to persist past the callback lifetime, but the lexer will
handle necessary cleanup on failure.
Backend uses of the JSON parser don't need to use this flag, since the
parser's allocations will occur in a short lived memory context.
A -o option has been added to test_json_parser_incremental to exercise
the new setJsonLexContextOwnsTokens() API, and the test_json_parser TAP
tests make use of it. (The test program now cleans up allocated memory,
so that tests can be usefully run under leak sanitizers.)
Author: Jacob Champion
Discussion: https://postgr.es/m/CAOYmi+kb38EciwyBQOf9peApKGwraHqA7pgzBkvoUnw5BRfS1g@mail.gmail.com
1. The error reporting of "port setrequested list-of-packages..."
changed, hiding errors we were relying on to know if all packages in our
list were already installed. Use a loop instead.
2. The cached MacPorts installation was shared between PostgreSQL
major branches, though each branch wanted different packages. Add the
list of packages to cache key, so that different branches, when tested
in one github account/repo such as postgres/postgres, stop fighting with
each other, adding and removing packages.
Back-patch to 15 where CI began.
Author: Thomas Munro <thomas.munro@gmail.com>
Author: Nazir Bilal Yavuz <byavuz81@gmail.com>
Suggested-by: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/au2uqfuy2nf43nwy2txmc5t2emhwij7kzupygto3d2ffgtrdgr%40ckvrlwyflnh2
Commit ccd38024bc, which introduced the pg_signal_autovacuum_worker
role, added a call to pgstat_get_beentry_by_proc_number() for the
purpose of determining whether the process is an autovacuum worker.
This function calls pgstat_read_current_status(), which can be
fairly expensive and may return cached, out-of-date information.
Since we just need to look up the target backend's BackendType, and
we already know its ProcNumber, we can instead inspect the
BackendStatusArray directly, which is much less expensive and
possibly more up-to-date. There are some caveats with this
approach (which are documented in the code), but it's still
substantially better than before.
Reported-by: Andres Freund
Reviewed-by: Andres Freund
Discussion: https://postgr.es/m/ujenaa2uabzfkwxwmfifawzdozh3ljr7geozlhftsuosgm7n7q%40g3utqqyyosb6
Emitting each variable separately is unnecessarily verbose / hard to skim
over. Emit the whole thing in one ereport() to address that.
Also remove program name and function reference from the message. The former
doesn't seem particularly helpful and the latter is provided by the elog.c
infrastructure these days.
Reviewed-by: Heikki Linnakangas <hlinnaka@iki.fi>
Reviewed-by: Peter Eisentraut <peter@eisentraut.org>
Discussion: https://postgr.es/m/leouteo5ozcrux3fepuhtbp6c56tbfd4naxeokidbx7m75cabz@hhw6g4urlowt
This commit introduces regression tests to validate incorrect settings
for the ON_ERROR, LOG_VERBOSITY, and REJECT_LIMIT options in file_fdw.
Author: Atsushi Torikoshi
Reviewed-by: Fujii Masao
Suggested-by: Yugo Nagata
Discussion: https://postgr.es/m/20241113231706.09e5b5ea9640289312835be8@sraoss.co.jp
During pgbench's table initialization, progress updates could display
leftover characters from the previous message if the new message
was shorter. This commit resolves the issue by appending spaces to
the current message to fully overwrite any remaining characters from
the previous line.
Back-patch to all the supported versions.
Author: Yushi Ogiwara, Tatsuo Ishii, Fujii Masao
Reviewed-by: Tatsuo Ishii, Fujii Masao
Discussion: https://postgr.es/m/9a9b8b95b6a709877ae48ad5b0c59bb9@oss.nttdata.com
We added pg_constraint rows for all not-null constraints, first for
tables and later for domains; but while the ones for tables were
reverted, the ones for domains were not. However, we did accidentally
revert ruleutils.c support for the ones on domains in 6f8bb7c1e9,
which breaks running pg_get_constraintdef() on them. Put that back.
This is only needed in branch 17, because we've reinstated this code in
branch master with commit 14e87ffa5c. Add some new tests in both
branches.
I couldn't find anything else that needs de-reverting.
Reported-by: Erki Eessaar <erki.eessaar@taltech.ee>
Reviewed-by: Magnus Hagander <magnus@hagander.net>
Discussion: https://postgr.es/m/AS8PR01MB75110350415AAB8BBABBA1ECFE222@AS8PR01MB7511.eurprd01.prod.exchangelabs.com
Commit 9044fc1d45 added some files from upstream LLVM. These files
have different whitespace rules, which make the git whitespace checks
powered by gitattributes fail. To fix, add those files to the exclude
list.
This reverts commit 2cf91ccb73.
When using the old msvcrt.dll, MinGW would supply its own dummy version
of _configthreadlocale() that just returns -1 if you try to use it. For
a time we tolerated that to shut the build farm up. We would fall back
to code that was enough for the tests to pass, but it would surely have
risked crashing a real multithreaded program.
We don't need that kludge anymore, because we can count on ucrt. We
expect the real _configthreadlocale() to be present, and the ECPG tests
will now fail if it isn't. The workaround was dead code and it's time
to revert it.
(A later patch still under review proposes to remove this use of
_configthreadlocale() completely but we're unwinding this code in
steps.)
Reviewed-by: Peter Eisentraut <peter@eisentraut.org>
Discussion: https://postgr.es/m/d9e7731c-ca1b-477c-9298-fa51e135574a%40eisentraut.org
Historically we tolerated the absence of various C runtime library
features for the benefit of the MinGW tool chain, because it used
ancient msvcrt.dll for a long period of time. It now uses ucrt by
default (like Windows 10+, Visual Studio 2015+), and that's the only
configuration we're testing.
In practice, we effectively required ucrt already in PostgreSQL 17, when
commit 8d9a9f03 required _create_locale etc, first available in
msvcr120.dll (Visual Studio 2013, the last of the pre-ucrt series of
runtimes), and for MinGW users that practically meant ucrt because it
was difficult or impossible to use msvcr120.dll. That may even not have
been the first such case, but old MinGW configurations had already
dropped off our testing radar so we weren't paying much attention.
This commit formalizes the requirement. It also removes a couple of
obsolete comments that discussed msvcrt.dll limitations, and some tests
of !defined(_MSC_VER) to imply msvcrt.dll. There are many more
anachronisms, but it'll take some time to figure out how to remove them
all. APIs affected relate to locales, UTF-8, threads, large files and
more.
Thanks to Peter Eisentraut for the documentation change. It's not
really necessary to talk about ucrt explicitly in such a short section,
since it's the default for MinGW-w64 and MSYS2. It's enough to prune
references and broken links to much older tools.
Reviewed-by: Peter Eisentraut <peter@eisentraut.org>
Discussion: https://postgr.es/m/d9e7731c-ca1b-477c-9298-fa51e135574a%40eisentraut.org
All modern Windows systems have _configthreadlocale(). It was first
introduced in msvcr80.dll from Visual Studio 2005. Historically, MinGW
was stuck on even older msvcrt.dll, but added its own dummy
implementation of the function when using msvcrt.dll years ago anyway,
effectively rendering the configure test useless. In practice we don't
encounter the dummy anymore because modern MinGW uses ucrt.
Reviewed-by: Peter Eisentraut <peter@eisentraut.org>
Discussion: https://postgr.es/m/CWZBBRR6YA8D.8EHMDRGLCKCD%40neon.tech
This allows for example using LIKE with case-insensitive collations.
There was previously no internal implementation of this, so it was met
with a not-supported error. This adds the internal implementation and
removes the error. The implementation follows the specification of
the SQL standard for this.
Unlike with deterministic collations, the LIKE matching cannot go
character by character but has to go substring by substring. For
example, if we are matching against LIKE 'foo%bar', we can't start by
looking for an 'f', then an 'o', but instead with have to find
something that matches 'foo'. This is because the collation could
consider substrings of different lengths to be equal. This is all
internal to MatchText() in like_match.c.
The changes in GenericMatchText() in like.c just pass through the
locale information to MatchText(), which was previously not needed.
This matches exactly Generic_Text_IC_like() below.
ILIKE is not affected. (It's unclear whether ILIKE makes sense under
nondeterministic collations.)
This also updates match_pattern_prefix() in like_support.c to support
optimizing the case of an exact pattern with nondeterministic
collations. This was already alluded to in the previous code.
(includes documentation examples from Daniel Vérité and test cases
from Paul A Jungwirth)
Reviewed-by: Jian He <jian.universality@gmail.com>
Discussion: https://www.postgresql.org/message-id/flat/700d2e86-bf75-4607-9cf2-f5b7802f6e88@eisentraut.org
Currently, logical replication produces a generic error message when
targeting a subscriber-side table column that is either missing or
generated. The error message can be misleading for generated columns.
This patch introduces a specific error message to clarify the issue when
generated columns are involved.
Author: Shubham Khanna
Reviewed-by: Peter Smith, Vignesh C, Amit Kapila
Discussion: https://postgr.es/m/CAHv8RjJBvYtqU7OAofBizOmQOK2Q8h+w9v2_cQWxT_gO7er3Aw@mail.gmail.com
When using a pipeline, a transaction starts from the first command and
is committed with a Sync message or when the pipeline ends.
Functions like IsInTransactionBlock() or PreventInTransactionBlock()
were already able to understand a pipeline as being in a transaction
block, but it was not the case of CheckTransactionBlock(). This
function is called for example to generate a WARNING for SET LOCAL,
complaining that it is used outside of a transaction block.
The current state of the code caused multiple problems, like:
- SET LOCAL executed at any stage of a pipeline issued a WARNING, even
if the command was at least second in line where the pipeline is in a
transaction state.
- LOCK TABLE failed when invoked at any step of a pipeline, even if it
should be able to work within a transaction block.
The pipeline protocol assumes that the first command of a pipeline is
not part of a transaction block, and that any follow-up commands is
considered as within a transaction block.
This commit changes the backend so as an implicit transaction block is
started each time the first Execute message of a pipeline has finished
processing, with this implicit transaction block ended once a sync is
processed. The checks based on XACT_FLAGS_PIPELINING in the routines
checking if we are in a transaction block are not necessary: it is
enough to rely on the existing ones.
Some tests are added to pgbench, that can be backpatched down to v17
when \syncpipeline is involved and down to v14 where \startpipeline and
\endpipeline are available. This is unfortunately limited regarding the
error patterns that can be checked, but it provides coverage for various
pipeline combinations to check if these succeed or fail. These tests
are able to capture the case of SET LOCAL's WARNING. The author has
proposed a different feature to improve the coverage by adding similar
meta-commands to psql where error messages could be checked, something
more useful for the cases where commands cannot be used in transaction
blocks, like REINDEX CONCURRENTLY or VACUUM. This is considered as
future work for v18~.
Author: Anthonin Bonnefoy
Reviewed-by: Jelte Fennema-Nio, Michael Paquier
Discussion: https://postgr.es/m/CAO6_XqrWO8uNBQrSu5r6jh+vTGi5Oiyk4y8yXDORdE2jbzw8xw@mail.gmail.com
Backpatch-through: 13
In commit 641a5b7a14, I removed "nbsp" characters from SVG files, not
realizing the SVG files were generated from GV files and that the "nbsp"
characters were caused by trailing ASCII spaces in GV files. This
commit restores the "nbsp" SVG characters and adds a GV comment about
how the trailing spaces cause the "nbsp" output.
Reported-by: Peter Eisentraut
Discussion: https://postgr.es/m/2c5dd601-b245-4092-9c27-6d1ad51609df%40eisentraut.org
Backpatch-through: master
The error messages in CreateWaitEventSet() made it hard to know whether the
syscall or AcquireExternalFD() failed. This is particularly relevant because
AcquireExternalFD() imposes a lower limit than what would cause syscalls fail
with EMFILE.
I did not change the message in libpqsrv_connect_prepare(), which is the one
other use of AcquireExternalFD() in our codebase, as the error message already
is less ambiguous.
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/xjjx7r4xa7beixuu4qtkdhnwdbchrrpo3gaeb3jsbinvvdiat5@cwjw55mna5of
Most came in during the 17 cycle, so backpatch there. Some
(particularly reorderbuffer.h) are very old, but backpatching doesn't
seem useful.
Like commits c9d2977519, c4f113e8fe.
Commit a8ccf4e93 uses the same table name "distinct_tbl" in both
select_distinct.sql and select_distinct_on.sql, which could cause
conflicts when these two test scripts are run in parallel.
Fix by renaming the table in select_distinct_on.sql to
"distinct_on_tbl".
Per buildfarm (via Tom Lane)
Discussion: https://postgr.es/m/1572004.1732583549@sss.pgh.pa.us
This utility has been using hardcoded values for relkind and
relpersistence in its queries generated. These queries are switched to
use CppAsString2() instead, with the values fetched directly from the
header of pg_class. This has the advantage of making the code more
self-documented, as it becomes unnecessary to look at a header for the
meaning of a value.
There should be no functional changes; the queries are generated the
same way as before this commit.
Reviewed-by: Nathan Bossart, Daniel Gustafsson, Álvaro Herrera, Karina
Litskevich
Discussion: https://postgr.es/m/ZxIvemDk0Ob1RGwh@paquier.xyz
The function get_param_path_clause_serials() is used to get the set of
pushed-down clauses enforced within a parameterized Path. Since we
don't currently support parameterized MergeAppend paths, and it
doesn't look like that is going to change anytime soon (as explained
in the comments for generate_orderedappend_paths), we don't need to
consider MergeAppendPath in this function.
This change won't make any measurable difference in performance; it's
just for clarity's sake.
Author: Richard Guo
Reviewed-by: Andrei Lepikhov
Discussion: https://postgr.es/m/CAMbWs4_Puie4DQ2ODvjQB_3CxYkUODnrJm8jn_ObMAcrjYNW7Q@mail.gmail.com
The ordering of DISTINCT items is semantically insignificant, so we
can reorder them as needed. In fact, in the parser, we absorb the
sorting semantics of the sortClause as much as possible into the
distinctClause, ensuring that one clause is a prefix of the other.
This can help avoid a possible need to re-sort.
In this commit, we attempt to adjust the DISTINCT keys to match the
input path's pathkeys. This can likewise help avoid re-sorting, or
allow us to use incremental-sort to save efforts.
For DISTINCT ON expressions, the parser already ensures that they
match the initial ORDER BY expressions. When reordering the DISTINCT
keys, we must ensure that the resulting pathkey list matches the
initial distinctClause pathkeys.
This introduces a new GUC, enable_distinct_reordering, which allows
the optimization to be disabled if needed.
Author: Richard Guo
Reviewed-by: Andrei Lepikhov
Discussion: https://postgr.es/m/CAMbWs48dR26cCcX0f=8bja2JKQPcU64136kHk=xekHT9xschiQ@mail.gmail.com
If passed a read-write expanded object pointer, the EEOP_NULLIF
code would hand that same pointer to the equality function
and then (unless equality was reported) also return the same
pointer as its value. This is no good, because a function that
receives a read-write expanded object pointer is fully entitled
to scribble on or even delete the object, thus corrupting the
NULLIF output. (This problem is likely unobservable with the
equality functions provided in core Postgres, but it's easy to
demonstrate with one coded in plpgsql.)
To fix, make sure the pointer passed to the equality function
is read-only. We can still return the original read-write
pointer as the NULLIF result, allowing optimization of later
operations.
Per bug #18722 from Alexander Lakhin. This has been wrong
since we invented expanded objects, so back-patch to all
supported branches.
Discussion: https://postgr.es/m/18722-fd9e645448cc78b4@postgresql.org
This WARNING appeared because SearchSysCacheLocked1() read
cc_relisshared before catcache initialization, when the field is false
unconditionally. On the basis of reading false there, it constructed a
locktag as though pg_tablespace weren't relisshared. Only shared
catalogs could be affected, and only GRANT TABLESPACE was affected in
practice. SearchSysCacheLocked1() callers use one other shared-relation
syscache, DATABASEOID. DATABASEOID is initialized by the end of
CheckMyDatabase(), making the problem unreachable for pg_database.
Back-patch to v13 (all supported versions). This has no known impact
before v16, where ExecGrant_common() first appeared. Earlier branches
avoid trouble by having a separate ExecGrant_Tablespace() that doesn't
use LOCKTAG_TUPLE. However, leaving this unfixed in v15 could ensnare a
future back-patch of a SearchSysCacheLocked1() call.
Reported by Aya Iwata.
Discussion: https://postgr.es/m/OS7PR01MB11964507B5548245A7EE54E70EA212@OS7PR01MB11964.jpnprd01.prod.outlook.com
Peter Eisentraut