If the non-recursive part of a recursive CTE ended up using
TTSOpsBufferHeapTuple as the table slot type, then a duplicate value
could cause an Assert failure in CheckOpSlotCompatibility() when
checking the hash table for the duplicate value. The expected slot type
for the deform step was TTSOpsMinimalTuple so the Assert failed when the
TTSOpsBufferHeapTuple slot was used.
This is a long-standing bug which we likely didn't notice because it
seems much more likely that the non-recursive term would have required
projection and used a TTSOpsVirtual slot, which CheckOpSlotCompatibility
is ok with.
There doesn't seem to be any harm done here other than the Assert
failure. Both TTSOpsMinimalTuple and TTSOpsBufferHeapTuple slot types
require tuple deformation, so the EEOP_*_FETCHSOME ExprState step would
have properly existed in the ExprState.
The solution is to pass NULL for the ExecBuildGroupingEqual's 'lops'
parameter. This means the ExprState's EEOP_*_FETCHSOME step won't
expect a fixed slot type. This makes CheckOpSlotCompatibility() happy as
no checking is performed when the ExprEvalStep is not expecting a fixed
slot type.
Reported-by: Richard Guo
Reviewed-by: Tom Lane
Discussion: https://postgr.es/m/CAMbWs4-8U9q2LAtf8+ghV11zeUReA3AmrYkxzBEv0vKnDxwkKA@mail.gmail.com
Backpatch-through: 13, all supported versions
If a dshash table grows very large (e.g., the dshash table for
cumulative statistics when there are millions of tables), resizing
it may fail with an error like:
ERROR: invalid DSA memory alloc request size 1073741824
To fix, permit dshash resizing to allocate more than 1 GB by
providing the DSA_ALLOC_HUGE flag.
Reported-by: Andreas Scherbaum
Author: Matthias van de Meent
Reviewed-by: Cédric Villemain, Michael Paquier, Andres Freund
Discussion: https://postgr.es/m/80a12d59-0d5e-4c54-866c-e69cd6536471%40pgug.de
Backpatch-through: 13
Since commit 97550c0711, these failed with
"PANIC: proc_exit() called in child process" due to uninitialized or
stale MyProcPid. That was reachable if close() failed in
ClosePostmasterPorts() or setlocale(category, "C") failed, both
unlikely. Back-patch to v13 (all supported versions).
Discussion: https://postgr.es/m/20241208034614.45.nmisch@google.com
Our parallel-mode code only works when we are executing a query
in full, so ExecutePlan must disable parallel mode when it is
asked to do partial execution. The previous logic for this
involved passing down a flag (variously named execute_once or
run_once) from callers of ExecutorRun or PortalRun. This is
overcomplicated, and unsurprisingly some of the callers didn't
get it right, since it requires keeping state that not all of
them have handy; not to mention that the requirements for it were
undocumented. That led to assertion failures in some corner
cases. The only state we really need for this is the existing
QueryDesc.already_executed flag, so let's just put all the
responsibility in ExecutePlan. (It could have been done in
ExecutorRun too, leading to a slightly shorter patch -- but if
there's ever more than one caller of ExecutePlan, it seems better
to have this logic in the subroutine than the callers.)
This makes those ExecutorRun/PortalRun parameters unnecessary.
In master it seems okay to just remove them, returning the
API for those functions to what it was before parallelism.
Such an API break is clearly not okay in stable branches,
but for them we can just leave the parameters in place after
documenting that they do nothing.
Per report from Yugo Nagata, who also reviewed and tested
this patch. Back-patch to all supported branches.
Discussion: https://postgr.es/m/20241206062549.710dc01cf91224809dd6c0e1@sraoss.co.jp
pgstat_write_statsfile() discards any entries marked as dropped from
being written to the stats file at shutdown, and also included an
assertion based on the same condition.
The intention of the assertion is to track that no pgstats entries
should be left around as terminating backends should drop any entries
they still hold references on before the stats file is written by the
checkpointer, and it not worth taking down the server in this case if
there is a bug making that possible.
Let's improve the comment of this area to document clearly what's
intended.
Based on a discussion with Bertrand Drouvot and Anton A. Melnikov.
Author: Bertrand Drouvot
Discussion: https://postgr.es/m/a13e8cdf-b97a-4ecb-8f42-aaa367974e29@postgrespro.ru
Backpatch-through: 15
818119afcc has introduced the "generation" concept in pgstats entries,
incremented a counter when a pgstats entry is reinitialized, but it did
not count on the fact that backends still holding local references to
such entries need to be refreshed if the cache age is outdated. The
previous logic only updated local references when an entry was dropped,
but it needs also to consider entries that are reinitialized.
This matters for replication slot stats (as well as custom pgstats kinds
in 18~), where concurrent drops and creates of a slot could cause
incorrect stats to be locally referenced. This would lead to an
assertion failure at shutdown when writing out the stats file, as the
backend holding an outdated local reference would not be able to drop
during its shutdown sequence the stats entry that should be dropped, as
the last process holding a reference to the stats entry. The
checkpointer was then complaining about such an entry late in the
shutdown sequence, after the shutdown checkpoint is finished with the
control file updated, causing the stats file to not be generated. In
non-assert builds, the entry would just be skipped with the stats file
written.
Note that only logical replication slots use statistics.
A test case based on TAP is added to test_decoding, where a persistent
connection peeking at a slot's data is kept with concurrent drops and
creates of the same slot. This is based on the isolation test case that
Anton has sent. As it requires a node shutdown with a check to make
sure that the stats file is written with this specific sequence of
events, TAP is used instead.
Reported-by: Anton A. Melnikov
Reviewed-by: Bertrand Drouvot
Discussion: https://postgr.es/m/56bf8ff9-dd8c-47b2-872a-748ede82af99@postgrespro.ru
Backpatch-through: 15
When short-circuiting WindowAgg node evaluation on the top-level
WindowAgg node using quals on monotonic window functions, because the
WindowAgg run condition can mean there's no need to evaluate subsequent
window function results in the same partition once the run condition
becomes false, it was possible that the executor would use stale results
from the previous invocation of the window function in some cases.
A fix for this was partially done by a5832722, but that commit only
fixed the issue for non-top-level WindowAgg nodes. I mistakenly thought
that the top-level WindowAgg didn't have this issue, but Jayesh's example
case clearly shows that's incorrect. At the time, I also thought that
this only affected 32-bit systems as all window functions which then
supported run conditions returned BIGINT, however, that's wrong as
ExecProject is still called and that could cause evaluation of any other
window function belonging to the same WindowAgg node, one of which may
return a byref type.
The only queries affected by this are WindowAggs with a "Run Condition"
which contains at least one window function with a byref result type,
such as lead() or lag() on a byref column. The window clause must also
contain a PARTITION BY clause (without a PARTITION BY, execution of the
WindowAgg stops immediately when the run condition becomes false and
there's no risk of using the stale results).
Reported-by: Jayesh Dehankar
Discussion: https://postgr.es/m/193261e2c4d.3dd3cd7c1842.871636075166132237@zohocorp.com
Backpatch-through: 15, where WindowAgg run conditions were added
Usually an entry in pg_amop or pg_amproc does not need a dependency on
its amoplefttype/amoprighttype/amproclefttype/amprocrighttype types,
because there is an indirect dependency via the argument types of its
referenced operator or procedure, or via the opclass it belongs to.
However, for some support procedures in some index AMs, the argument
types of the support procedure might not mention the column data type
at all. Also, the amop/amproc entry might be treated as "loose" in
the opfamily, in which case it lacks a dependency on any particular
opclass; or it might be a cross-type entry having a reference to a
datatype that is not its opclass' opcintype.
The upshot of all this is that there are cases where a datatype can
be dropped while leaving behind amop/amproc entries that mention it,
because there is no path in pg_depend showing that those entries
depend on that type. Such entries are harmless in normal activity,
because they won't get used, but they cause problems for maintenance
actions such as dropping the operator family. They also cause pg_dump
to produce bogus output. The previous commit put a band-aid on the
DROP OPERATOR FAMILY failure, but a real fix is needed.
To fix, add pg_depend entries showing that a pg_amop/pg_amproc entry
depends on its lefttype/righttype. To avoid bloating pg_depend too
much, skip this if the referenced operator or function has that type
as an input type. (I did not bother with considering the possible
indirect dependency via the opclass' opcintype; at least in the
reported case, that wouldn't help anyway.)
Probably, the reason this has escaped notice for so long is that
add-on datatypes and relevant opclasses/opfamilies are usually
packaged as extensions nowadays, so that there's no way to drop
a type without dropping the referencing opclasses/opfamilies too.
Still, in the absence of pg_depend entries there's nothing that
constrains DROP EXTENSION to drop the opfamily entries before the
datatype, so it seems possible for a DROP failure to occur anyway.
The specific case that was reported doesn't fail in v13, because
v13 prefers to attach the support procedure to the opclass not the
opfamily. But it's surely possible to construct other edge cases
that do fail in v13, so patch that too.
Per report from Yoran Heling. Back-patch to all supported branches.
Discussion: https://postgr.es/m/Z1MVCOh1hprjK5Sf@gmai021
Yoran Heling reported a case where a data type could be dropped
while references to its OID remain behind in pg_amproc. This
causes getObjectDescription to fail, which blocks dropping the
operator family (since our DROP code likes to construct descriptions
of everything it's dropping). The proper fix for this requires
adding more pg_depend entries. But to allow DROP to go through with
already-corrupt catalogs, tweak getObjectDescription to print "???"
for the type instead of failing when it processes such an entry.
I changed the logic for pg_amop similarly, for consistency,
although it is not known that the problem can manifest in pg_amop.
Per report from Yoran Heling. Back-patch to all supported
branches (although the problem may be unreachable in v13).
Discussion: https://postgr.es/m/Z1MVCOh1hprjK5Sf@gmai021
These format codes produce or consume strings of digits, so they
should be labeled with is_digit = true, but they were not.
This has effect in only one place, where is_next_separator()
is checked to see if the preceding format code should slurp up
all the available digits. Thus, with a format such as '...SSFF3'
with remaining input '12345', the 'SS' code would consume all
five digits (and then complain about seconds being out of range)
when it should eat only two digits.
Per report from Nick Davies. This bug goes back to d589f9446
where the FFn codes were introduced, so back-patch to v13.
Discussion: https://postgr.es/m/AM8PR08MB6356AC979252CFEA78B56678B6312@AM8PR08MB6356.eurprd08.prod.outlook.com
Previously, it set only DELAY_CHKPT_COMPLETE. That was important,
because it meant that if the XLOG_SMGR_TRUNCATE record preceded a
XLOG_CHECKPOINT_ONLINE record in the WAL, then the truncation would also
happen on disk before the XLOG_CHECKPOINT_ONLINE record was
written.
However, it didn't guarantee that the sync request for the truncation
was processed before the XLOG_CHECKPOINT_ONLINE record was written. By
setting DELAY_CHKPT_START, we guarantee that if an XLOG_SMGR_TRUNCATE
record is written to WAL before the redo pointer of a concurrent
checkpoint, the sync request queued by that operation must be processed
by that checkpoint, rather than being left for the following one.
This is a refinement of commit 412ad7a556. Back-patch to all supported
releases, like that commit.
Author: Robert Haas <robertmhaas@gmail.com>
Reported-by: Thomas Munro <thomas.munro@gmail.com>
Discussion: https://postgr.es/m/CA%2BhUKG%2B-2rjGZC2kwqr2NMLBcEBp4uf59QT1advbWYF_uc%2B0Aw%40mail.gmail.com
Commit 352f6f2d used %d instead of %lu to format DWORD (unsigned long)
with psprintf(). The _WIN32_WINNT value recently changed for MinGW in
REL_15_STABLE (commit d700e8d7), so the code was suddenly being
compiled, with warnings from gcc.
The warnings were already fixed in 16+ by commits 495ed0ef and a9bc04b2
after the _WIN32_WINNT value was increase there. 14 and 13 didn't warn
because they still use a lower value for MinGW, and supported versions
of Visual Studio should compile the code in all live branches but don't
check our format string.
The change doesn't affect the result: sizeof(int) == sizeof(long) on
this platform, and the values are computed with expressions that cannot
exceed INT_MAX so were never interpreted as negative.
Back-patch the formatting change from those commits into 13-15. This
should turn CI's 15 branch green again and stop fairywren from warning
about that on 15.
Reported-by: Andres Freund <andres@anarazel.de>
Reported-by: Peter Eisentraut <peter@eisentraut.org>
Discussion: https://postgr.es/m/t2vjrcb3bloxf5qqvxjst6r7lvrefqyecxgt2koy5ho5b5glr2%40yuupmm6whgob
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
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
RelationSyncCache, the hash table in charge of tracking the relation
schemas sent through pgoutput, was forgetting to free the TupleDesc
associated to the two slots used to store the new and old tuples,
causing some memory to be leaked each time a relation is invalidated
when the slots of an existing relation entry are cleaned up.
This is rather hard to notice as the bloat is pretty minimal, but a
long-running WAL sender would be in trouble over time depending on the
workload. sysbench has proved to be pretty good at showing the problem,
coupled with some memory monitoring of the WAL sender.
Issue introduced in 52e4f0cd47, that has added row filters for tables
logically replicated.
Author: Boyu Yang
Reviewed-by: Michael Paquier, Hou Zhijie
Discussion: https://postgr.es/m/DM3PR84MB3442E14B340E553313B5C816E3252@DM3PR84MB3442.NAMPRD84.PROD.OUTLOOK.COM
Backpatch-through: 15
Ordinarily transformSetOperationTree will collect all UNION/
INTERSECT/EXCEPT steps into the setOperations tree of the topmost
Query, so that leaf queries do not contain any setOperations.
However, it cannot thus flatten a subquery that also contains
WITH, ORDER BY, FOR UPDATE, or LIMIT. I (tgl) forgot that in
commit 07b4c48b6 and wrote an assertion in rule deparsing that
a leaf's setOperations would always be empty.
If it were nonempty then we would want to parenthesize the subquery
to ensure that the output represents the setop nesting correctly
(e.g. UNION below INTERSECT had better get parenthesized). So
rather than just removing the faulty Assert, let's change it into
an additional case to check to decide whether to add parens. We
don't expect that the additional case will ever fire, but it's
cheap insurance.
Man Zeng and Tom Lane
Discussion: https://postgr.es/m/tencent_7ABF9B1F23B0C77606FC5FE3@qq.com
In the dim past we figured it was okay to ignore collations
when combining UNION set-operation nodes into a single N-way
UNION operation. I believe that was fine at the time, but
it stopped being fine when we added nondeterministic collations:
the semantics of distinct-ness are affected by those. v17 made
it even less fine by allowing per-child sorting operations to
be merged via MergeAppend, although I think we accidentally
avoided any live bug from that.
Add a check that collations match before deciding that two
UNION nodes are equivalent. I also failed to resist the
temptation to comment plan_union_children() a little better.
Back-patch to all supported branches (v13 now), since they
all have nondeterministic collations.
Discussion: https://postgr.es/m/3605568.1731970579@sss.pgh.pa.us
fixempties() counts the number of in-arcs in the regex NFA and then
allocates an array of that many arc pointers. If the NFA contains no
arcs, this amounts to malloc(0) for which some platforms return NULL.
The code mistakenly treats that as indicating out-of-memory. Thus,
we can get a bogus "out of memory" failure for some unsatisfiable
regexes.
This happens only in v15 and earlier, since bea3d7e38 switched to
using palloc() rather than bare malloc(). And at least of the
platforms in the buildfarm, only AIX seems to return NULL. So the
impact is pretty narrow. But I don't especially want to ship code
that is failing its own regression tests, so let's fix this for
this week's releases.
A quick code survey says that there is only the one place in
src/backend/regex/ that is at risk of doing malloc(0), so we'll just
band-aid that place. A more future-proof fix could be to install a
malloc() wrapper similar to pg_malloc(). But this code seems unlikely
to change much more in the affected branches, so that's probably
overkill.
The only known test case for this involves a complemented character
class in a bracket expression, for example [^\s\S], and we didn't
support that in v13. So it may be that the problem is unreachable
in v13. But I'm not 100% sure of that, so patch v13 too.
Discussion: https://postgr.es/m/661fd81b-f069-8f30-1a41-e195c57449b4@gmail.com
After commit 5a2fed911a, the catalog state
resulting from these commands ceased to affect sessions. Restore the
longstanding behavior, which is like beginning the session with a SET
ROLE command. If cherry-picking the CVE-2024-10978 fixes, default to
including this, too. (This fixes an unintended side effect of fixing
CVE-2024-10978.) Back-patch to v12, like that commit. The release team
decided to include v12, despite the original intent to halt v12 commits
earlier this week.
Tom Lane and Noah Misch. Reported by Etienne LAFARGE.
Discussion: https://postgr.es/m/CADOZwSb0UsEr4_UTFXC5k7=fyyK8uKXekucd+-uuGjJsGBfxgw@mail.gmail.com
Previously LogicalIncreaseRestartDecodingForSlot() accidentally
accepted any LSN as the candidate_lsn and candidate_valid after the
restart_lsn of the replication slot was updated, so it potentially
caused the restart_lsn to move backwards.
A scenario where this could happen in logical replication is: after a
logical replication restart, based on previous candidate_lsn and
candidate_valid values in memory, the restart_lsn advances upon
receiving a subscriber acknowledgment. Then, logical decoding restarts
from an older point, setting candidate_lsn and candidate_valid based
on an old RUNNING_XACTS record. Subsequent subscriber acknowledgments
then update the restart_lsn to an LSN older than the current value.
In the reported case, after WAL files were removed by a checkpoint,
the retreated restart_lsn prevented logical replication from
restarting due to missing WAL segments.
This change essentially modifies the 'if' condition to 'else if'
condition within the function. The previous code had an asymmetry in
this regard compared to LogicalIncreaseXminForSlot(), which does
almost the same thing for different fields.
The WAL removal issue was reported by Hubert Depesz Lubaczewski.
Backpatch to all supported versions, since the bug exists since 9.4
where logical decoding was introduced.
Reviewed-by: Tomas Vondra, Ashutosh Bapat, Amit Kapila
Discussion: https://postgr.es/m/Yz2hivgyjS1RfMKs%40depesz.com
Discussion: https://postgr.es/m/85fff40e-148b-4e86-b921-b4b846289132%40vondra.me
Backpatch-through: 13
In commit 08c0d6ad6 which introduced "rainbow" arcs in regex NFAs,
I didn't think terribly hard about what to do when creating the color
complement of a rainbow arc. Clearly, the complement cannot match any
characters, and I took the easy way out by just not building any arcs
at all in the complement arc set. That mostly works, but Nikolay
Shaplov found a case where it doesn't: if we decide to delete that
sub-NFA later because it's inside a "{0}" quantifier, delsub()
suffered an assertion failure. That's because delsub() relies on
the target sub-NFA being fully connected. That was always true
before, and the best fix seems to be to restore that property.
Hence, invent a new arc type CANTMATCH that can be generated in
place of an empty color complement, and drop it again later when we
start NFA optimization. (At that point we don't need to do delsub()
any more, and besides there are other cases where NFA optimization can
lead to disconnected subgraphs.)
It appears that this bug has no consequences in a non-assert-enabled
build: there will be some transiently leaked NFA states/arcs, but
they'll get cleaned up eventually. Still, we don't like assertion
failures, so back-patch to v14 where rainbow arcs were introduced.
Per bug #18708 from Nikolay Shaplov.
Discussion: https://postgr.es/m/18708-f94f2599c9d2c005@postgresql.org
This fixes a set of race conditions with cumulative statistics where a
shared stats entry could be dropped while it should still be valid in
the event when it is reused: an entry may refer to a different object
but requires the same hash key. This can happen with various stats
kinds, like:
- Replication slots that compute internally an index number, for
different slot names.
- Stats kinds that use an OID in the object key, where a wraparound
causes the same key to be used if an OID is used for the same object.
- As of PostgreSQL 18, custom pgstats kinds could also be an issue,
depending on their implementation.
This issue is fixed by introducing a counter called "generation" in the
shared entries via PgStatShared_HashEntry, initialized at 0 when an
entry is created and incremented when the same entry is reused, to avoid
concurrent issues on drop because of other backends still holding a
reference to it. This "generation" is copied to the local copy that a
backend holds when looking at an object, then cross-checked with the
shared entry to make sure that the entry is not dropped even if its
"refcount" justifies that if it has been reused.
This problem could show up when a backend shuts down and needs to
discard any entries it still holds, causing statistics to be removed
when they should not, or even an assertion failure. Another report
involved a failure in a standby after an OID wraparound, where the
startup process would FATAL on a "can only drop stats once", stopping
recovery abruptly. The buildfarm has been sporadically complaining
about the problem, as well, but the window is hard to reach with the
in-core tests.
Note that the issue can be reproduced easily by adding a sleep before
dshash_find() in pgstat_release_entry_ref() to enlarge the problematic
window while repeating test_decoding's isolation test oldest_xmin a
couple of times, for example, as pointed out by Alexander Lakhin.
Reported-by: Alexander Lakhin, Peter Smith
Author: Kyotaro Horiguchi, Michael Paquier
Reviewed-by: Bertrand Drouvot
Discussion: https://postgr.es/m/CAA4eK1KxuMVyAryz_Vk5yq3ejgKYcL6F45Hj9ZnMNBS-g+PuZg@mail.gmail.com
Discussion: https://postgr.es/m/17947-b9554521ad963c9c@postgresql.org
Backpatch-through: 15
The current code calls array_eq() and does not provide FmgrInfo. This commit
provides initialization of FmgrInfo and uses C collation as the safe option
for text comparison because we don't know anything about the semantics of
opclass options.
Backpatch to 13, where opclass options were introduced.
Reported-by: Nicolas Maus
Discussion: https://postgr.es/m/18692-72ea398df3ec6712%40postgresql.org
Backpatch-through: 13
Commit 5a2fed911 had an unexpected side-effect: the parallel worker
launched for the new test case would fail if it couldn't use a
superuser-reserved connection slot. The reason that test failed
while all our pre-existing ones worked is that the connection
privilege tests in InitPostgres had been based on the superuserness
of the leader's AuthenticatedUserId, but after the rearrangements
of 5a2fed911 we were testing the superuserness of CurrentUserId,
which the new test case deliberately made to be a non-superuser.
This all seems very accidental and probably not the behavior we really
want, but a security patch is no time to be redesigning things.
Pending some discussion about desirable semantics, hack it so that
InitPostgres continues to pay attention to the superuserness of
AuthenticatedUserId when starting a parallel worker.
Nathan Bossart and Tom Lane, per buildfarm member sawshark.
Security: CVE-2024-10978
The SQL spec mandates that SET SESSION AUTHORIZATION implies
SET ROLE NONE. We tried to implement that within the lowest-level
functions that manipulate these settings, but that was a bad idea.
In particular, guc.c assumes that it doesn't matter in what order
it applies GUC variable updates, but that was not the case for these
two variables. This problem, compounded by some hackish attempts to
work around it, led to some security-grade issues:
* Rolling back a transaction that had done SET SESSION AUTHORIZATION
would revert to SET ROLE NONE, even if that had not been the previous
state, so that the effective user ID might now be different from what
it had been.
* The same for SET SESSION AUTHORIZATION in a function SET clause.
* If a parallel worker inspected current_setting('role'), it saw
"none" even when it should see something else.
Also, although the parallel worker startup code intended to cope
with the current role's pg_authid row having disappeared, its
implementation of that was incomplete so it would still fail.
Fix by fully separating the miscinit.c functions that assign
session_authorization from those that assign role. To implement the
spec's requirement, teach set_config_option itself to perform "SET
ROLE NONE" when it sets session_authorization. (This is undoubtedly
ugly, but the alternatives seem worse. In particular, there's no way
to do it within assign_session_authorization without incompatible
changes in the API for GUC assign hooks.) Also, improve
ParallelWorkerMain to directly set all the relevant user-ID variables
instead of relying on some of them to get set indirectly. That
allows us to survive not finding the pg_authid row during worker
startup.
In v16 and earlier, this includes back-patching 9987a7bf3 which
fixed a violation of GUC coding rules: SetSessionAuthorization
is not an appropriate place to be throwing errors from.
Security: CVE-2024-10978
If a CTE, subquery, sublink, security invoker view, or coercion
projection references a table with row-level security policies, we
neglected to mark the plan as potentially dependent on which role
is executing it. This could lead to later executions in the same
session returning or hiding rows that should have been hidden or
returned instead.
Reported-by: Wolfgang Walther
Reviewed-by: Noah Misch
Security: CVE-2024-10976
Backpatch-through: 12
Commit ac04aa84a put the shutoff for this into the planner, which is
not ideal because it doesn't prevent us from re-using a previously
made parallel plan. Revert the planner change and instead put the
shutoff into InitializeParallelDSM, modeling it on the existing code
there for recovering from failure to allocate a DSM segment.
However, that code path is mostly untested, and testing a bit harder
showed there's at least one bug: ExecHashJoinReInitializeDSM is not
prepared for us to have skipped doing parallel DSM setup. I also
thought the Assert in ReinitializeParallelWorkers is pretty
ill-advised, and replaced it with a silent Min() operation.
The existing test case added by ac04aa84a serves fine to test this
version of the fix, so no change needed there.
Patch by me, but thanks to Noah Misch for the core idea that we
could shut off worker creation when !INTERRUPTS_CAN_BE_PROCESSED.
Back-patch to v12, as ac04aa84a was.
Discussion: https://postgr.es/m/CAC-SaSzHUKT=vZJ8MPxYdC_URPfax+yoA1hKTcF4ROz_Q6z0_Q@mail.gmail.com
If the collation of any join key column doesn’t match the collation of
the corresponding partition key, partitionwise joins can yield incorrect
results. For example, rows that would match under the join key collation
might be located in different partitions due to the partitioning
collation. In such cases, a partitionwise join would yield different
results from a non-partitionwise join, so disallow it in such cases.
Reported-by: Tender Wang <tndrwang@gmail.com>
Author: Jian He <jian.universality@gmail.com>
Reviewed-by: Tender Wang <tndrwang@gmail.com>
Reviewed-by: Junwang Zhao <zhjwpku@gmail.com>
Discussion: https://postgr.es/m/CAHewXNno_HKiQ6PqyLYfuqDtwp7KKHZiH1J7Pqyz0nr+PS2Dwg@mail.gmail.com
Backpatch-through: 12
If the collation of any grouping column doesn’t match the collation of
the corresponding partition key, partitionwise grouping can yield
incorrect results. For example, rows that would be grouped under the
grouping collation may end up in different partitions under the
partitioning collation. In such cases, full partitionwise grouping
would produce results that differ from those without partitionwise
grouping, so disallowed that.
Partial partitionwise aggregation is still allowed, as the Finalize
step reconciles partition-level aggregates with grouping requirements
across all partitions, ensuring that the final output remains
consistent.
This commit also fixes group_by_has_partkey() by ensuring the
RelabelType node is stripped from grouping expressions when matching
them to partition key expressions to avoid false mismatches.
Bug: #18568
Reported-by: Webbo Han <1105066510@qq.com>
Author: Webbo Han <1105066510@qq.com>
Reviewed-by: Tender Wang <tndrwang@gmail.com>
Reviewed-by: Aleksander Alekseev <aleksander@timescale.com>
Reviewed-by: Jian He <jian.universality@gmail.com>
Discussion: https://postgr.es/m/18568-2a9afb6b9f7e6ed3@postgresql.org
Discussion: https://postgr.es/m/tencent_9D9103CDA420C07768349CC1DFF88465F90A@qq.com
Discussion: https://postgr.es/m/CAHewXNno_HKiQ6PqyLYfuqDtwp7KKHZiH1J7Pqyz0nr+PS2Dwg@mail.gmail.com
Backpatch-through: 12
Now that lstat() reports junction points with S_IFLNK/S_ISLINK(), and
unlink() can unlink them, there is no need for conditional code for
Windows in a few places. That was expressed by testing for WIN32 or
S_ISLNK, which we can now constant-fold.
The coding around pgwin32_is_junction() was a bit suspect anyway, as we
never checked for errors, and we also know that errors can be spuriously
reported because of transient sharing violations on this OS. The
lstat()-based code has handling for that.
This also reverts 4fc6b6ee on master only. That was done because
lstat() didn't previously work for symlinks (junction points), but now
it does.
Tested-by: Andrew Dunstan <andrew@dunslane.net>
Discussion: https://postgr.es/m/CA%2BhUKGLfOOeyZpm5ByVcAt7x5Pn-%3DxGRNCvgiUPVVzjFLtnY0w%40mail.gmail.com
(cherry picked from commit 5fc88c5d53)
Author: Thomas Munro <tmunro@postgresql.org>
Author: Alexandra Wang <alexandra.wang.oss@gmail.com>
Supply a new memory manager for RuntimeDyld, to avoid crashes in
generated code caused by memory placement that can overflow a 32 bit
data type. This is a drop-in replacement for the
llvm::SectionMemoryManager class in the LLVM library, with Michael
Smith's proposed fix from
https://www.github.com/llvm/llvm-project/pull/71968.
We hereby slurp it into our own source tree, after moving into a new
namespace llvm::backport and making some minor adjustments so that it
can be compiled with older LLVM versions as far back as 12. It's harder
to make it work on even older LLVM versions, but it doesn't seem likely
that people are really using them so that is not investigated for now.
The problem could also be addressed by switching to JITLink instead of
RuntimeDyld, and that is the LLVM project's recommended solution as
the latter is about to be deprecated. We'll have to do that soon enough
anyway, and then when the LLVM version support window advances far
enough in a few years we'll be able to delete this code. Unfortunately
that wouldn't be enough for PostgreSQL today: in most relevant versions
of LLVM, JITLink is missing or incomplete.
Several other projects have already back-ported this fix into their fork
of LLVM, which is a vote of confidence despite the lack of commit into
LLVM as of today. We don't have our own copy of LLVM so we can't do
exactly what they've done; instead we have a copy of the whole patched
class so we can pass an instance of it to RuntimeDyld.
The LLVM project hasn't chosen to commit the fix yet, and even if it
did, it wouldn't be back-ported into the releases of LLVM that most of
our users care about, so there is not much point in waiting any longer
for that. If they make further changes and commit it to LLVM 19 or 20,
we'll still need this for older versions, but we may want to
resynchronize our copy and update some comments.
The changes that we've had to make to our copy can be seen by diffing
our SectionMemoryManager.{h,cpp} files against the ones in the tree of
the pull request. Per the LLVM project's license requirements, a copy
is in SectionMemoryManager.LICENSE.
This should fix the spate of crash reports we've been receiving lately
from users on large memory ARM systems.
Back-patch to all supported releases.
Co-authored-by: Thomas Munro <thomas.munro@gmail.com>
Co-authored-by: Anthonin Bonnefoy <anthonin.bonnefoy@datadoghq.com>
Reviewed-by: Anthonin Bonnefoy <anthonin.bonnefoy@datadoghq.com>
Reviewed-by: Daniel Gustafsson <daniel@yesql.se> (license aspects)
Reported-by: Anthonin Bonnefoy <anthonin.bonnefoy@datadoghq.com>
Discussion: https://postgr.es/m/CAO6_Xqr63qj%3DSx7HY6ZiiQ6R_JbX%2B-p6sTPwDYwTWZjUmjsYBg%40mail.gmail.com
PgStat_HashKey is currently initialized in a way that could result in
random data if the structure has any padding bytes. The structure
has no padding bytes currently, fortunately, but it could become a
problem should the structure change at some point in the future.
The code is changed to use some memset(0) so as any padding would be
handled properly, as it would be surprising to see random failures in
the pgstats entry lookups. PgStat_HashKey is a structure internal to
pgstats, and an ABI change could be possible in the scope of a bug fix,
so backpatch down to 15 where this has been introduced.
Author: Bertrand Drouvot
Reviewed-by: Jelte Fennema-Nio, Michael Paquier
Discussion: https://postgr.es/m/Zyb7RW1y9dVfO0UH@ip-10-97-1-34.eu-west-3.compute.internal
Backpatch-through: 15
Commit a07e03fd8f enlarged the work done
here under the pg_class heap buffer lock. Two preexisting actions are
best done before holding that lock. Both RelationGetNumberOfBlocks()
and visibilitymap_count() do I/O, and the latter might exclusive-lock a
visibility map buffer. Moving these reduces contention and risk of
undetected LWLock deadlock. Back-patch to v12, like that commit.
Discussion: https://postgr.es/m/20241031200139.b4@rfd.leadboat.com
This reverts commit 95c5acb3fc (v17) and
counterparts in each other non-master branch. If released, that commit
would have caused a worst-in-years minor release regression, via
undetected LWLock self-deadlock. This commit and its self-deadlock fix
warrant more bake time in the master branch.
Reported by Alexander Lakhin.
Discussion: https://postgr.es/m/10ec0bc3-5933-1189-6bb8-5dec4114558e@gmail.com
* In DetachPartitionFinalize() we were applying a tuple conversion map
to tuples that didn't need one, which can lead to erratic behavior if
a partitioned table has a partition with a different column order, as
reported by Alexander Lakhin. This was introduced by 53af9491a0.
Don't do that. Also, modify a recently added test case to exercise
this.
* The same function as well as CloneFkReferenced() were acquiring
AccessShareLock on a partition, only to have CreateTrigger() later
acquire ShareRowExclusiveLock on it. This can lead to deadlock by
lock escalation, unnecessarily. Avoid that by acquiring the stronger
lock to begin with. This probably dates back to branch 12, but I have
never seen a report of this being a problem in the field.
* Innocuous but wasteful: also introduced by 53af9491a0, we were
reading a pg_constraint tuple from syscache that we don't need, as
reported by Tender Wang. Don't.
Backpatch to 15.
Discussion: https://postgr.es/m/461e9c26-2076-8224-e119-84998b6a784e@gmail.com
Commit a07e03fd8f changed inplace updates
to wait for heap_update() commands like GRANT TABLE and GRANT DATABASE.
By keeping the pin during that wait, a sequence of autovacuum workers
and an uncommitted GRANT starved one foreground LockBufferForCleanup()
for six minutes, on buildfarm member sarus. Prevent, at the cost of a
bit of complexity. Back-patch to v12, like the earlier commit. That
commit and heap_inplace_lock() have not yet appeared in any release.
Discussion: https://postgr.es/m/20241026184936.ae.nmisch@google.com
A buffer lock won't stop a reader having already checked tuple
visibility. If a vac_update_datfrozenid() and then a crash happened
during inplace update of a relfrozenxid value, datfrozenxid could
overtake relfrozenxid. That could lead to "could not access status of
transaction" errors. Back-patch to v12 (all supported versions). In
v14 and earlier, this also back-patches the assertion removal from
commit 7fcf2faf9c.
Discussion: https://postgr.es/m/20240620012908.92.nmisch@google.com
The inplace update survives ROLLBACK. The inval didn't, so another
backend's DDL could then update the row without incorporating the
inplace update. In the test this fixes, a mix of CREATE INDEX and ALTER
TABLE resulted in a table with an index, yet relhasindex=f. That is a
source of index corruption. Back-patch to v12 (all supported versions).
The back branch versions don't change WAL, because those branches just
added end-of-recovery SIResetAll(). All branches change the ABI of
extern function PrepareToInvalidateCacheTuple(). No PGXN extension
calls that, and there's no apparent use case in extensions.
Reviewed by Nitin Motiani and (in earlier versions) Andres Freund.
Discussion: https://postgr.es/m/20240523000548.58.nmisch@google.com
An inplace update's invalidation messages are part of its transaction's
commit record. However, the update survives even if its transaction
aborts or we stop recovery before replaying its transaction commit.
After recovery, a backend that started in recovery could update the row
without incorporating the inplace update. That could result in a table
with an index, yet relhasindex=f. That is a source of index corruption.
This bulk invalidation avoids the functional consequences. A future
change can fix the !RecoveryInProgress() scenario without changing the
WAL format. Back-patch to v17 - v12 (all supported versions). v18 will
instead add invalidations to WAL.
Discussion: https://postgr.es/m/20240618152349.7f.nmisch@google.com
... to fix bugs when the referenced table is partitioned.
The catalog representation we chose for foreign keys connecting
partitioned tables (in commit f56f8f8da6) is inconvenient, in the
sense that a standalone table has a different way to represent the
constraint when referencing a partitioned table, than when the same
table becomes a partition (and vice versa). Because of this, we need to
create additional catalog rows on detach (pg_constraint and pg_trigger),
and remove them on attach. We were doing some of those things, but not
all of them, leading to missing catalog rows in certain cases.
The worst problem seems to be that we are missing action triggers after
detaching a partition, which means that you could update/delete rows
from the referenced partitioned table that still had referencing rows on
that table, the server failing to throw the required errors.
!!!
Note that this means existing databases with FKs that reference
partitioned tables might have rows that break relational integrity, on
tables that were once partitions on the referencing side of the FK.
Another possible problem is that trying to reattach a table
that had been detached would fail indicating that internal triggers
cannot be found, which from the user's point of view is nonsensical.
In branches 15 and above, we fix this by creating a new helper function
addFkConstraint() which is in charge of creating a standalone
pg_constraint row, and repurposing addFkRecurseReferencing() and
addFkRecurseReferenced() so that they're only the recursive routine for
each side of the FK, and they call addFkConstraint() to create
pg_constraint at each partitioning level and add the necessary triggers.
These new routines can be used during partition creation, partition
attach and detach, and foreign key creation. This reduces redundant
code and simplifies the flow.
In branches 14 and 13, we have a much simpler fix that consists on
simply removing the constraint on detach. The reason is that those
branches are missing commit f4566345cf, which reworked the way this
works in a way that we didn't consider back-patchable at the time.
We opted to leave branch 12 alone, because it's different from branch 13
enough that the fix doesn't apply; and because it is going in EOL mode
very soon, patching it now might be worse since there's no way to undo
the damage if it goes wrong.
Existing databases might need to be repaired.
In the future we might want to rethink the catalog representation to
avoid this problem, but for now the code seems to do what's required to
make the constraints operate correctly.
Co-authored-by: Jehan-Guillaume de Rorthais <jgdr@dalibo.com>
Co-authored-by: Tender Wang <tndrwang@gmail.com>
Co-authored-by: Alvaro Herrera <alvherre@alvh.no-ip.org>
Reported-by: Guillaume Lelarge <guillaume@lelarge.info>
Reported-by: Jehan-Guillaume de Rorthais <jgdr@dalibo.com>
Reported-by: Thomas Baehler (SBB CFF FFS) <thomas.baehler2@sbb.ch>
Discussion: https://postgr.es/m/20230420144344.40744130@karst
Discussion: https://postgr.es/m/20230705233028.2f554f73@karst
Discussion: https://postgr.es/m/GVAP278MB02787E7134FD691861635A8BC9032@GVAP278MB0278.CHEP278.PROD.OUTLOOK.COM
Discussion: https://postgr.es/m/18541-628a61bc267cd2d3@postgresql.org
