If we redirected a replicated tuple operation into a partition child
table, and then tried to fire AFTER triggers for that event, the
relation cache entry for the child table was already closed. This has
no visible ill effects as long as the entry is still there and still
valid, but an unluckily-timed cache flush could result in a crash or
other misbehavior.
To fix, postpone the ExecCleanupTupleRouting call (which is what
closes the child table) until after we've fired triggers. This
requires a bit of refactoring so that the cleanup function can
have access to the necessary state.
In HEAD, I took the opportunity to simplify some of worker.c's
function APIs based on use of the new ApplyExecutionData struct.
However, it doesn't seem safe/practical to back-patch that aspect,
at least not without a lot of analysis of possible interactions
with a04daa97a.
In passing, add an Assert to afterTriggerInvokeEvents to catch
such cases. This seems worthwhile because we've grown a number
of fairly unstructured ways of calling AfterTriggerEndQuery.
Back-patch to v13, where worker.c grew the ability to deal with
partitioned target tables.
Discussion: https://postgr.es/m/3382681.1621381328@sss.pgh.pa.us
This was previously allowed, but I think that was just an oversight.
It's a clear violation of the rule that a generated column cannot
depend on itself or other generated columns. Moreover, because the
code was relying on the assumption that no such cross-references
exist, it was pretty easy to crash ALTER TABLE and perhaps other
places. Even if you managed not to crash, you got quite unstable,
implementation-dependent results.
Per report from Vitaly Ustinov.
Back-patch to v12 where GENERATED came in.
Discussion: https://postgr.es/m/CAM_DEiWR2DPT6U4xb-Ehigozzd3n3G37ZB1+867zbsEVtYoJww@mail.gmail.com
We consider this supported (though I've got my doubts that it's a
good idea, because tableoid is not immutable). However, several
code paths failed to fill the field in soon enough, causing such
a GENERATED expression to see zero or the wrong value. This
occurred when ALTER TABLE adds a new GENERATED column to a table
with existing rows, and during regular INSERT or UPDATE on a
foreign table with GENERATED columns.
Noted during investigation of a report from Vitaly Ustinov.
Back-patch to v12 where GENERATED came in.
Discussion: https://postgr.es/m/CAM_DEiWR2DPT6U4xb-Ehigozzd3n3G37ZB1+867zbsEVtYoJww@mail.gmail.com
COMMIT/ROLLBACK necessarily destroys all snapshots within the session.
The original implementation of intra-procedure transactions just
cavalierly did that, ignoring the fact that this left us executing in
a rather different environment than normal. In particular, it turns
out that handling of toasted datums depends rather critically on there
being an outer ActiveSnapshot: otherwise, when SPI or the core
executor pop whatever snapshot they used and return, it's unsafe to
dereference any toasted datums that may appear in the query result.
It's possible to demonstrate "no known snapshots" and "missing chunk
number N for toast value" errors as a result of this oversight.
Historically this outer snapshot has been held by the Portal code,
and that seems like a good plan to preserve. So add infrastructure
to pquery.c to allow re-establishing the Portal-owned snapshot if it's
not there anymore, and add enough bookkeeping support that we can tell
whether it is or not.
We can't, however, just re-establish the Portal snapshot as part of
COMMIT/ROLLBACK. As in normal transaction start, acquiring the first
snapshot should wait until after SET and LOCK commands. Hence, teach
spi.c about doing this at the right time. (Note that this patch
doesn't fix the problem for any PLs that try to run intra-procedure
transactions without using SPI to execute SQL commands.)
This makes SPI's no_snapshots parameter rather a misnomer, so in HEAD,
rename that to allow_nonatomic.
replication/logical/worker.c also needs some fixes, because it wasn't
careful to hold a snapshot open around AFTER trigger execution.
That code doesn't use a Portal, which I suspect someday we're gonna
have to fix. But for now, just rearrange the order of operations.
This includes back-patching the recent addition of finish_estate()
to centralize the cleanup logic there.
This also back-patches commit 2ecfeda3e into v13, to improve the
test coverage for worker.c (it was that test that exposed that
worker.c's snapshot management is wrong).
Per bug #15990 from Andreas Wicht. Back-patch to v11 where
intra-procedure COMMIT was added.
Discussion: https://postgr.es/m/15990-eee2ac466b11293d@postgresql.org
While applying the truncate change, the logical apply worker acquires
RowExclusiveLock on the relation being truncated. This allowed truncate on
the relation at a time by two apply workers which lead to a deadlock. The
reason was that one of the workers after updating the pg_class tuple tries
to acquire SHARE lock on the relation and started to wait for the second
worker which has acquired RowExclusiveLock on the relation. And when the
second worker tries to update the pg_class tuple, it starts to wait for
the first worker which leads to a deadlock. Fix it by acquiring
AccessExclusiveLock on the relation before applying the truncate change as
we do for normal truncate operation.
Author: Peter Smith, test case by Haiying Tang
Reviewed-by: Dilip Kumar, Amit Kapila
Backpatch-through: 11
Discussion: https://postgr.es/m/CAHut+PsNm43p0jM+idTvWwiGZPcP0hGrHMPK9TOAkc+a4UpUqw@mail.gmail.com
exec_for_query() normally tries to prefetch a few rows at a time
from the query being iterated over, so as to reduce executor
entry/exit overhead. Unfortunately this is unsafe if we have
COMMIT or ROLLBACK within the loop, because there might be
TOAST references in the data that we prefetched but haven't
yet examined. Immediately after the COMMIT/ROLLBACK, we have
no snapshots in the session, meaning that VACUUM is at liberty
to remove recently-deleted TOAST rows.
This was originally reported as a case triggering the "no known
snapshots" error in init_toast_snapshot(), but even if you miss
hitting that, you can get "missing toast chunk", as illustrated
by the added isolation test case.
To fix, just disable prefetching in non-atomic contexts. Maybe
there will be performance complaints prompting us to work harder
later, but it's not clear at the moment that this really costs
much, and I doubt we'd want to back-patch any complicated fix.
In passing, adjust that error message in init_toast_snapshot()
to be a little clearer about the likely cause of the problem.
Patch by me, based on earlier investigation by Konstantin Knizhnik.
Per bug #15990 from Andreas Wicht. Back-patch to v11 where
intra-procedure COMMIT was added.
Discussion: https://postgr.es/m/15990-eee2ac466b11293d@postgresql.org
"typename" is a C++ keyword, so pg_upgrade.h fails to compile in C++.
Fortunately, there seems no likely reason for somebody to need to
do that. Nonetheless, it's project policy that all .h files should
pass cpluspluscheck, so rename the argument to fix that.
Oversight in 57c081de0; back-patch as that was. (The policy requiring
pg_upgrade.h to pass cpluspluscheck only goes back to v12, but it
seems best to keep this code looking the same in all branches.)
ForgetBackgroundWorker lacked any memory barrier at all, while
BackgroundWorkerStateChange had one but unaccountably did
additional manipulation of the slot after the barrier. AFAICS,
the rule must be that the barrier is immediately before setting
or clearing slot->in_use.
It looks like back in 9.6 when ForgetBackgroundWorker was first
written, there might have been some case for not needing a
barrier there, but I'm not very convinced of that --- the fact
that the load of bgw_notify_pid is in the caller doesn't seem
to guarantee no memory ordering problem. So patch 9.6 too.
It's likely that this doesn't fix any observable bug on Intel
hardware, but machines with weaker memory ordering rules could
have problems here.
Discussion: https://postgr.es/m/4046084.1620244003@sss.pgh.pa.us
Add a defensive "can't happen" error to code that handles nbtree posting
list splits (promote an existing assertion). This avoids a segfault in
the event of an insertion of a newitem that is somehow identical to an
existing non-pivot tuple in the index. An nbtree index should never
have two index tuples with identical TIDs.
This scenario is not particular unlikely in the event of any kind of
corruption that leaves the index in an inconsistent state relative to
the heap relation that is indexed. There are two known reports of
preventable hard crashes. Doing nothing seems unacceptable given the
general expectation that nbtree will cope reasonably well with corrupt
data.
Discussion: https://postgr.es/m/CAH2-Wz=Jr_d-dOYEEmwz0-ifojVNWho01eAqewfQXgKfoe114w@mail.gmail.com
Backpatch: 13-, where nbtree deduplication was introduced.
Formerly we just relied on operator classes that assert longValuesOK
to eventually shorten the leaf value enough to fit on an index page.
That fails since the introduction of INCLUDE-column support (commit
09c1c6ab4), because the INCLUDE columns might alone take up more
than a page, meaning no amount of leaf-datum compaction will get
the job done. At least with spgtextproc.c, that leads to an infinite
loop, since spgtextproc.c won't throw an error for not being able
to shorten the leaf datum anymore.
To fix without breaking cases that would otherwise work, add logic
to spgdoinsert() to verify that the leaf tuple size is decreasing
after each "choose" step. Some opclasses might not decrease the
size on every single cycle, and in any case, alignment roundoff
of the tuple size could obscure small gains. Therefore, allow
up to 10 cycles without additional savings before throwing an
error. (Perhaps this number will need adjustment, but it seems
quite generous right now.)
As long as we've developed this logic, let's back-patch it.
The back branches don't have INCLUDE columns to worry about, but
this seems like a good defense against possible bugs in operator
classes. We already know that an infinite loop here is pretty
unpleasant, so having a defense seems to outweigh the risk of
breaking things. (Note that spgtextproc.c is actually the only
known opclass with longValuesOK support, so that this is all moot
for known non-core opclasses anyway.)
Per report from Dilip Kumar.
Discussion: https://postgr.es/m/CAFiTN-uxP_soPhVG840tRMQTBmtA_f_Y8N51G7DKYYqDh7XN-A@mail.gmail.com
Knowing that a buggy opclass could cause an infinite insertion loop,
spgdoinsert() intended to allow its loop to be interrupted by query
cancel. However, that never actually worked, because in iterations
after the first, we'd be holding buffer lock(s) which would cause
InterruptHoldoffCount to be positive, preventing servicing of the
interrupt.
To fix, check if an interrupt is pending, and if so fall out of
the insertion loop and service the interrupt after we've released
the buffers. If it was indeed a query cancel, that's the end of
the matter. If it was a non-canceling interrupt reason, make use
of the existing provision to retry the whole insertion. (This isn't
as wasteful as it might seem, since any upper-level index tuples we
already created should be usable in the next attempt.)
While there's no known instance of such a bug in existing release
branches, it still seems like a good idea to back-patch this to
all supported branches, since the behavior is fairly nasty if a
loop does happen --- not only is it uncancelable, but it will
quickly consume memory to the point of an OOM failure. In any
case, this code is certainly not working as intended.
Per report from Dilip Kumar.
Discussion: https://postgr.es/m/CAFiTN-uxP_soPhVG840tRMQTBmtA_f_Y8N51G7DKYYqDh7XN-A@mail.gmail.com
Split up CHECK_FOR_INTERRUPTS() to provide an additional macro
INTERRUPTS_PENDING_CONDITION(), which just tests whether an
interrupt is pending without attempting to service it. This is
useful in situations where the caller knows that interrupts are
blocked, and would like to find out if it's worth the trouble
to unblock them.
Also add INTERRUPTS_CAN_BE_PROCESSED(), which indicates whether
CHECK_FOR_INTERRUPTS() can be relied on to clear the pending interrupt.
This commit doesn't actually add any uses of the new macros,
but a follow-on bug fix will do so. Back-patch to all supported
branches to provide infrastructure for that fix.
Alvaro Herrera and Tom Lane
Discussion: https://postgr.es/m/20210513155351.GA7848@alvherre.pgsql
Make sample like_regex match string values of the root object instead of the
whole document. The corrected example seems to represent a more relevant
use case.
Backpatch to 12, when jsonpath was introduced.
Discussion: https://postgr.es/m/13440f8b-4c1f-5875-c8e3-f3f65606af2f%40xs4all.nl
Author: Erik Rijkers
Reviewed-by: Michael Paquier, Alexander Korotkov
Backpatch-through: 12
The worker.c global wrconn is only meant to be used by logical apply/
tablesync workers, but there are other variables with the same name. To
reduce future confusion rename the global from "wrconn" to
"LogRepWorkerWalRcvConn".
While this is just cosmetic, it seems better to backpatch it all the way
back to 10 where this code appeared, to avoid future backpatching
issues.
Author: Peter Smith <smithpb2250@gmail.com>
Discussion: https://postgr.es/m/CAHut+Pu7Jv9L2BOEx_Z0UtJxfDevQSAUW2mJqWU+CtmDrEZVAg@mail.gmail.com
Several queries in the privileges regression test cause the planner
to apply the plpgsql function "leak()" to every element of the
histogram for atest12.b. Since commit 0c882e52a increased the size
of that histogram to 10000 entries, the test invokes that function
over 100000 times, which takes an absolutely unreasonable amount of
time in clobber-cache-always mode.
However, there's no real reason why that has to be a plpgsql
function: for the purposes of this test, all that matters is that
it not be marked leakproof. So we can replace the plpgsql
implementation with a direct call of int4lt, which has the same
behavior and is orders of magnitude faster. This is expected to
cut several hours off the buildfarm cycle time for CCA animals.
It has some positive impact in normal builds too, though that's
probably lost in the noise.
Back-patch to v13 where 0c882e52a came in.
Discussion: https://postgr.es/m/575884.1620626638@sss.pgh.pa.us
It's unusual to have any resjunk columns in an ON CONFLICT ... UPDATE
list, but it can happen when MULTIEXPR_SUBLINK SubPlans are present.
If it happens, the ON CONFLICT UPDATE code path would end up storing
tuples that include the values of the extra resjunk columns. That's
fairly harmless in the short run, but if new columns are added to
the table then the values would become accessible, possibly leading
to malfunctions if they don't match the datatypes of the new columns.
This had escaped notice through a confluence of missing sanity checks,
including
* There's no cross-check that a tuple presented to heap_insert or
heap_update matches the table rowtype. While it's difficult to
check that fully at reasonable cost, we can easily add assertions
that there aren't too many columns.
* The output-column-assignment cases in execExprInterp.c lacked
any sanity checks on the output column numbers, which seems like
an oversight considering there are plenty of assertion checks on
input column numbers. Add assertions there too.
* We failed to apply nodeModifyTable's ExecCheckPlanOutput() to
the ON CONFLICT UPDATE tlist. That wouldn't have caught this
specific error, since that function is chartered to ignore resjunk
columns; but it sure seems like a bad omission now that we've seen
this bug.
In HEAD, the right way to fix this is to make the processing of
ON CONFLICT UPDATE tlists work the same as regular UPDATE tlists
now do, that is don't add "SET x = x" entries, and use
ExecBuildUpdateProjection to evaluate the tlist and combine it with
old values of the not-set columns. This adds a little complication
to ExecBuildUpdateProjection, but allows removal of a comparable
amount of now-dead code from the planner.
In the back branches, the most expedient solution seems to be to
(a) use an output slot for the ON CONFLICT UPDATE projection that
actually matches the target table, and then (b) invent a variant of
ExecBuildProjectionInfo that can be told to not store values resulting
from resjunk columns, so it doesn't try to store into nonexistent
columns of the output slot. (We can't simply ignore the resjunk columns
altogether; they have to be evaluated for MULTIEXPR_SUBLINK to work.)
This works back to v10. In 9.6, projections work much differently and
we can't cheaply give them such an option. The 9.6 version of this
patch works by inserting a JunkFilter when it's necessary to get rid
of resjunk columns.
In addition, v11 and up have the reverse problem when trying to
perform ON CONFLICT UPDATE on a partitioned table. Through a
further oversight, adjust_partition_tlist() discarded resjunk columns
when re-ordering the ON CONFLICT UPDATE tlist to match a partition.
This accidentally prevented the storing-bogus-tuples problem, but
at the cost that MULTIEXPR_SUBLINK cases didn't work, typically
crashing if more than one row has to be updated. Fix by preserving
resjunk columns in that routine. (I failed to resist the temptation
to add more assertions there too, and to do some minor code
beautification.)
Per report from Andres Freund. Back-patch to all supported branches.
Security: CVE-2021-32028
While we were (mostly) careful about ensuring that the dimensions of
arrays aren't large enough to cause integer overflow, the lower bound
values were generally not checked. This allows situations where
lower_bound + dimension overflows an integer. It seems that that's
harmless so far as array reading is concerned, except that array
elements with subscripts notionally exceeding INT_MAX are inaccessible.
However, it confuses various array-assignment logic, resulting in a
potential for memory stomps.
Fix by adding checks that array lower bounds aren't large enough to
cause lower_bound + dimension to overflow. (Note: this results in
disallowing cases where the last subscript position would be exactly
INT_MAX. In principle we could probably allow that, but there's a lot
of code that computes lower_bound + dimension and would need adjustment.
It seems doubtful that it's worth the trouble/risk to allow it.)
Somewhat independently of that, array_set_element() was careless
about possible overflow when checking the subscript of a fixed-length
array, creating a different route to memory stomps. Fix that too.
Security: CVE-2021-32027
When building without --enable-dtrace, emit dummy
do {} while (0)
statements for the stubbed-out TRACE_POSTGRESQL_foo() macros
instead of empty macros that totally elide the original probe
statement.
This fixes the
warning: suggest braces around empty body in an ‘if’ statement [-Wempty-body]
introduced by b94409a02f.
Author: Craig Ringer <craig.ringer@2ndquadrant.com>
Discussion: https://www.postgresql.org/message-id/flat/20210504221531.cfvpmmdfsou6eitb%40alap3.anarazel.de
This patch replaces use of the global "wrconn" variable in
AlterSubscription_refresh with a local variable of the same name, making
it consistent with other functions in subscriptioncmds.c (e.g.
DropSubscription).
The global wrconn is only meant to be used for logical apply/tablesync worker.
Abusing it this way is known to cause trouble if an apply worker
manages to do a subscription refresh, such as reported by Jeremy Finzel
and diagnosed by Andres Freund back in November 2020, at
https://www.postgresql.org/message-id/20201111215820.qihhrz7fayu6myfi@alap3.anarazel.de
Backpatch to 10. In branch master, also move the connection establishment
to occur outside the PG_TRY block; this way we can remove a test for NULL in
PG_FINALLY, and it also makes the code more consistent with similar code in
the same file.
Author: Peter Smith <peter.b.smith@fujitsu.com>
Reviewed-by: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>
Reviewed-by: Japin Li <japinli@hotmail.com>
Discussion: https://postgr.es/m/CAHut+Pu7Jv9L2BOEx_Z0UtJxfDevQSAUW2mJqWU+CtmDrEZVAg@mail.gmail.com
When ALTER TABLE .. ALTER CONSTRAINT changes deferrability properties
changed in a partitioned table, we failed to propagate those changes
correctly to partitions and to triggers. Repair by adding a recursion
mechanism to affect all derived constraints and all derived triggers.
(In particular, recurse to partitions even if their respective parents
are already in the desired state: it is possible for the partitions to
have been altered individually.) Because foreign keys involve tables in
two sides, we cannot use the standard ALTER TABLE recursion mechanism,
so we invent our own by following pg_constraint.conparentid down.
When ALTER TABLE .. ALTER CONSTRAINT is invoked on the derived
pg_constraint object that's automaticaly created in a partition as a
result of a constraint added to its parent, raise an error instead of
pretending to work and then failing to modify all the affected triggers.
Before this commit such a command would be allowed but failed to affect
all triggers, so it would silently misbehave. (Restoring dumps of
existing databases is not affected, because pg_dump does not produce
anything for such a derived constraint anyway.)
Add some tests for the case.
Backpatch to 11, where foreign key support was added to partitioned
tables by commit 3de241dba8. (A related change is commit f56f8f8da6
in pg12 which added support for FKs *referencing* partitioned tables;
this is what forces us to use an ad-hoc recursion mechanism for this.)
Diagnosed by Tom Lane from bug report from Ron L Johnson. As of this
writing, no reviews were offered.
Discussion: https://postgr.es/m/75fe0761-a291-86a9-c8d8-4906da077469@gmail.com
Discussion: https://postgr.es/m/3144850.1607369633@sss.pgh.pa.us
The OID of the constraint is used instead of the OID of the trigger --
an easy mistake to make. Apparently the object-alter hooks are not very
well tested :-(
Backpatch to 12, where this typo was introduced by 578b229718
Discussion: https://postgr.es/m/20210503231633.GA6994@alvherre.pgsql
When running ALTER TABLE t2 INHERIT t1, we must check that columns in
t2 that correspond to a generated column in t1 are also generated and
have the same generation expression. Otherwise, this would allow
creating setups that a normal CREATE TABLE sequence would not allow.
Discussion: https://www.postgresql.org/message-id/22de27f6-7096-8d96-4619-7b882932ca25@2ndquadrant.com
If dtrace is compiled in but disabled, the lwlock dtrace probes still
evaluate their arguments. Since PostgreSQL 13, T_NAME(lock) does
nontrivial work, so it should be avoided if not needed. To fix, make
these calls conditional on the *_ENABLED() macro corresponding to each
probe.
Reviewed-by: Craig Ringer <craig.ringer@enterprisedb.com>
Discussion: https://www.postgresql.org/message-id/CAGRY4nwxKUS_RvXFW-ugrZBYxPFFM5kjwKT5O+0+Stuga5b4+Q@mail.gmail.com
Mention specifically that you can't call aggregates, window functions,
or procedures this way (the inability to call SRFs was already
mentioned).
Also, the claim that PQfn doesn't support NULL arguments or results
has been a lie since we invented protocol 3.0. Not sure why this
text was never updated for that, but do it now.
Discussion: https://postgr.es/m/2039442.1615317309@sss.pgh.pa.us
Reject aggregates, window functions, and procedures. Aggregates
failed anyway, though with a somewhat obscure error message.
Window functions would hit an Assert or null-pointer dereference.
Procedures seemed to work as long as you didn't try to do
transaction control, but (a) transaction control is sort of the
point of a procedure, and (b) it's not entirely clear that no
bugs lurk in that path. Given the lack of testing of this area,
it seems safest to be conservative in what we support.
Also reject proretset functions, as the fastpath protocol can't
support returning a set.
Also remove an easily-triggered assertion that the given OID
isn't 0; the subsequent lookups can handle that case themselves.
Per report from Theodor-Arsenij Larionov-Trichkin.
Back-patch to all supported branches. (The procedure angle
only applies in v11+, of course.)
Discussion: https://postgr.es/m/2039442.1615317309@sss.pgh.pa.us
Commits 29aeda6e4 et al closed up some oversights involving not checking
for non-upgradable types within container types, such as arrays and
ranges. However, I only looked at version.c, failing to notice that
there were substantially-equivalent tests in check.c. (The division
of responsibility between those files is less than clear...)
In addition, because genbki.pl does not guarantee that auto-generated
rowtype OIDs will hold still across versions, we need to consider that
the composite type associated with a system catalog or view is
non-upgradable. It seems unlikely that someone would have a user
column declared that way, but if they did, trying to read it in another
PG version would likely draw "no such pg_type OID" failures, thanks
to the type OID embedded in composite Datums.
To support the composite and reg*-type cases, extend the recursive
query that does the search to allow any base query that returns
a column of pg_type OIDs, rather than limiting it to exactly one
starting type.
As before, back-patch to all supported branches.
Discussion: https://postgr.es/m/2798740.1619622555@sss.pgh.pa.us
Attempting to use this function with event triggers failed, as, since
its introduction in a676201, this code has never associated an object
name with event triggers. This addresses the failure by adding the
event trigger name to the set defining its object address.
Note that regression tests are added within event_trigger and not
object_address to avoid issues with concurrent connections in parallel
schedules.
Author: Joel Jacobson
Discussion: https://postgr.es/m/3c905e77-a026-46ae-8835-c3f6cd1d24c8@www.fastmail.com
Backpatch-through: 9.6
For some reason, the "julian" option for extract()/date_part() has
never gotten listed in the manual. Also, while Appendix B mentioned
in passing that we don't conform to the usual astronomical definition
that a Julian date starts at noon UTC, it was kind of vague about what
we do instead. Clarify that, and add an example showing how to get
the astronomical definition if you want it.
It's been like this for ages, so back-patch to all supported branches.
Discussion: https://postgr.es/m/1197050.1619123213@sss.pgh.pa.us
Previously it was documented that if using "-X none" option there was
no guarantee that all required WAL files were archived at the end of
pg_basebackup when taking a backup from the standby. But this limitation
was removed by commit 52f8a59dd9. Now, even when taking a backup
from the standby, pg_basebackup can wait for all required WAL files
to be archived. Therefore this commit removes such obsolete
description from the docs.
Also this commit adds new description about the limitation when
taking a backup from the standby, into the docs. The limitation is that
pg_basebackup cannot force the standbfy to switch to a new WAL file
at the end of backup, which may cause pg_basebackup to wait a long
time for the last required WAL file to be switched and archived,
especially when write activity on the primary is low.
Back-patch to v10 where the issue was introduced.
Reported-by: Kyotaro Horiguchi
Author: Kyotaro Horiguchi, Fujii Masao
Reviewed-by: Kyotaro Horiguchi, Fujii Masao
Discussion: https://postgr.es/m/20210420.133235.1342729068750553399.horikyota.ntt@gmail.com
Adopt a more consistent policy about what slot-type-specific
getsysattr functions should do when system attributes are not
available. To wit, they should all throw the same user-oriented
error, rather than variously crashing or emitting developer-oriented
messages.
This closes a identifiable problem in commits a71cfc56b and
3fb93103a (in v13 and v12), so back-patch into those branches,
along with a test case to try to ensure we don't break it again.
It is not known that any of the former crash cases are reachable
in HEAD, but this seems like a good safety improvement in any case.
Discussion: https://postgr.es/m/141051591267657@mail.yandex.ru
If the source and destination partitions don't have identical
rowtypes (for example, one has dropped columns the other lacks),
then the planSlot contents will be different because of that.
If the query has a RETURNING list that tries to return resjunk
columns out of the planSlot, that is columns from tables that
were joined to the target table, we'd get errors or wrong answers.
That's because we used the RETURNING list generated for the
destination partition, which expects a planSlot matching that
partition's subplan.
The most practical fix seems to be to convert the updated destination
tuple back to the source partition's rowtype, and then apply the
RETURNING list generated for the source partition. This avoids making
fragile assumptions about whether the per-subpartition subplans
generated all the resjunk columns in the same order.
This has been broken since v11 introduced cross-partition UPDATE.
The lack of field complaints shows that non-identical partitions
aren't a common case; therefore, don't stress too hard about
making the conversion efficient.
There's no such bug in HEAD, because commit 86dc90056 got rid of
per-target-relation variance in the contents of the planSlot.
Hence, patch v11-v13 only.
Amit Langote and Etsuro Fujita, small changes by me
Discussion: https://postgr.es/m/CA+HiwqE_UK1jTSNrjb8mpTdivzd3dum6mK--xqKq0Y9VmfwWQA@mail.gmail.com
An oversight introduced by the incremental-sort patches caused
"could not find pathkey item to sort" errors in some situations
where a sort key involves an aggregate or window function.
The basic problem here is that find_em_expr_usable_for_sorting_rel
isn't properly modeling what prepare_sort_from_pathkeys will do
later. Rather than hoping we can keep those functions in sync,
let's refactor so that they actually share the code for
identifying a suitable sort expression.
With this refactoring, tlist.c's tlist_member_ignore_relabel
is unused. I removed it in HEAD but left it in place in v13,
in case any extensions are using it.
Per report from Luc Vlaming. Back-patch to v13 where the
problem arose.
James Coleman and Tom Lane
Discussion: https://postgr.es/m/91f3ec99-85a4-fa55-ea74-33f85a5c651f@swarm64.com
Tom Lane