The call to XLogGetReplicationSlotMinimumLSN() might return a
greater LSN than the one given to the function. Subsequent segment
number calculations might then underflow, which could result in
unexpected behavior when removing or recyling WAL files. This was
introduced with max_slot_wal_keep_size in c655077639. To fix, skip
the block of code for replication slots if the LSN is greater.
Tom Lane [Thu, 27 Apr 2023 15:55:06 +0000 (11:55 -0400)]
In hstore_plpython, avoid crashing when return value isn't a mapping.
Python 3 changed the behavior of PyMapping_Check(), breaking the
test in plpython_to_hstore() that verifies whether a function result
to be transformed is acceptable. A backwards-compatible fix is to
first verify that the object doesn't pass PySequence_Check().
Perhaps accidentally, our other uses of PyMapping_Check() already
follow uses of PySequence_Check(), so that no other bugs were
created by this change.
Per bug #17908 from Alexander Lakhin. Back-patch to all supported
branches.
Michael Paquier [Tue, 25 Apr 2023 22:30:42 +0000 (07:30 +0900)]
Re-add tracking of wait event SLRUFlushSync
SLRUFlushSync has been accidently removed during dee663f, that has moved
the flush of the SLRU files to the checkpointer, so add it back. The
issue has been noticed by Thomas when checking for orphaned wait
events.
Author: Thomas Munro Reviewed-by: Bharath Rupireddy
Discussion: https://postgr.es/m/CA+hUKGK6tqm59KuF1z+h5Y8fsWcu5v8+84kduSHwRzwjB2aa_A@mail.gmail.com
Fix vacuum_cost_delay check for balance calculation.
Commit 1021bd6a89 excluded autovacuum workers from cost-limit balance
calculations when per-relation options were set. The code checks for
limit and cost_delay being greater than zero, but since cost_delay can
be set to -1 the test needs to check for greater than or zero.
Backpatch to all supported branches since 1021bd6a89 was backpatched
all the way at the time.
Michael Paquier [Tue, 25 Apr 2023 00:42:33 +0000 (09:42 +0900)]
Fix buffer refcount leak with FDW bulk inserts
The leak would show up when using batch inserts with foreign tables
included in a partition tree, as the slots used in the batch were not
reset once processed. In order to fix this problem, some
ExecClearTuple() are added to clean up the slots used once a batch is
filled and processed, mapping with the number of slots currently in use
as tracked by the counter ri_NumSlots.
This buffer refcount leak has been introduced in b676ac4 with the
addition of the executor facility to improve bulk inserts for FDWs, so
backpatch down to 14.
Alexander has provided the patch (slightly modified by me). The test
for postgres_fdw comes from me, based on the test case that the author
has sent in the report.
Tom Lane [Mon, 24 Apr 2023 18:19:46 +0000 (14:19 -0400)]
Fix memory leakage in plpgsql DO blocks that use cast expressions.
Commit 04fe805a1 modified plpgsql so that datatype casts make use of
expressions cached by plancache.c, in place of older code where these
expression trees were managed by plpgsql itself. However, I (tgl)
forgot that we use a separate, shorter-lived cast info hashtable in
DO blocks. The new mechanism thus resulted in session-lifespan
leakage of the plancache data once a DO block containing one or more
casts terminated. To fix, split the cast hash table into two parts,
one that tracks only the plancache's CachedExpressions and one that
tracks the expression state trees generated from them. DO blocks need
their own expression state trees and hence their own version of the
second hash table, but there's no reason they can't share the
CachedExpressions with regular plpgsql functions.
Per report from Ajit Awekar. Back-patch to v12 where the issue
was introduced.
Commit 6df7a9698bb accidentally included two identical prototypes for
default_multirange_selectivi() and commit 086cf1458c6 added a break;
statement where one was already present, thus duplicating it. While
there is no bug caused by this, fix by removing the duplicated lines
as they provide no value.
Backpatch the fix for duplicate prototypes to v14 and the duplicate
break statement fix to all supported branches to avoid backpatching
hazards due to the removal.
Reported-by: Anton Voloshin <a.voloshin@postgrespro.ru>
Discussion: https://postgr.es/m/0e69cb60-0176-f6d0-7e15-6478b7d85724@postgrespro.ru
Validate ltree siglen GiST option to be int-aligned
Unaligned siglen could lead to an unaligned access to subsequent key fields.
Backpatch to 13, where opclass options were introduced.
Reported-by: Alexander Lakhin
Bug: 17847
Discussion: https://postgr.es/m/17847-171232970bea406b%40postgresql.org Reviewed-by: Tom Lane, Pavel Borisov, Alexander Lakhin
Backpatch-through: 13
Tom Lane [Thu, 20 Apr 2023 22:12:32 +0000 (18:12 -0400)]
Use --strip-unneeded when stripping static libraries with GNU strip.
We've long used "--strip-unneeded" for shared libraries but plain
"-x" for static libraries when stripping symbols with GNU strip.
There doesn't seem to be any really good reason for that though,
since --strip-unneeded produces smaller output (as "-x" alone
does not remove debug symbols). Moreover it seems that
llvm-strip, although it identifies as GNU strip, misbehaves when
given "-x" for this purpose. It's unclear whether that's
intentional or a bug in llvm-strip, but in any case it seems like
changing to use --strip-unneeded in all cases should be a win.
Note that this doesn't change our behavior when dealing with
non-GNU strip.
Per gripes from Ed Maste and Palle Girgensohn. Back-patch,
in case anyone wants to use llvm-strip with stable branches.
David Rowley [Thu, 20 Apr 2023 22:02:25 +0000 (10:02 +1200)]
Fix list_copy_head() with empty Lists
list_copy_head() given an empty List would crash from trying to
dereference the List to obtain its length. Since NIL is how we represent
an empty List, we should just be returning another empty List in this
case.
list_copy_head() is new to v16, so let's fix it now before too many people
start coding around the buggy NIL behavior.
Reported-by: Miroslav Bendik
Discussion: https://postgr.es/m/CAPoEpV02WhawuWnmnKet6BqU63bEu7oec0pJc=nKMtPsHMzTXQ@mail.gmail.com
David Rowley [Thu, 20 Apr 2023 11:52:36 +0000 (23:52 +1200)]
Doc: clarify NULLS NOT DISTINCT use in unique indexes
indexes-unique.html mentioned nothing about the availability of NULLS NOT
DISTINCT to modify the NULLs-are-not-equal behavior of unique indexes.
Add this to the synopsis and clarify what it does regarding NULLs.
Author: David Gilman, David Rowley Reviewed-by: Corey Huinker
Discussion: https://postgr.es/m/CALBH9DDr3NLqzWop1z5uZE-M5G_GYUuAeHFHQeyzFbNd8W0d=Q@mail.gmail.com
Backpatch-through: 15, where NULLS NOT DISTINCT was added
Tom Lane [Tue, 18 Apr 2023 18:46:39 +0000 (14:46 -0400)]
Update time zone data files to tzdata release 2023c.
DST law changes in Egypt, Greenland, Morocco, and Palestine.
When observing Moscow time, Europe/Kirov and Europe/Volgograd now
use the abbreviations MSK/MSD instead of numeric abbreviations,
for consistency with other timezones observing Moscow time.
Also, America/Yellowknife is no longer distinct from America/Edmonton;
this affects some pre-1948 timestamps in that area.
Michael Paquier [Tue, 18 Apr 2023 02:20:47 +0000 (11:20 +0900)]
ecpg: Fix handling of strings in ORACLE compat code with SQLDA
When compiled with -C ORACLE, ecpg_get_data() had a one-off issue where
it would incorrectly store the null terminator byte to str[-1] when
varcharsize is 0, which is something that can happen when using SQLDA.
This would eat 1 byte from the previous field stored, corrupting the
results generated.
All the callers of ecpg_get_data() estimate and allocate enough storage
for the data received, and the fix of this commit relies on this
assumption. Note that this maps to the case where no padding or
truncation is required.
This issue has been introduced by 3b7ab43 with the Oracle compatibility
option, so backpatch down to v11.
Tom Lane [Mon, 17 Apr 2023 18:22:06 +0000 (14:22 -0400)]
Avoid trying to write an empty WAL record in log_newpage_range().
If the last few pages in the specified range are empty (all zero),
then log_newpage_range() could try to emit an empty WAL record
containing no FPIs. This at least upsets an Assert in
ReserveXLogInsertLocation, and might perhaps have bad real-world
consequences in non-assert builds.
This has been broken since log_newpage_range() was introduced,
but the case was hard if not impossible to hit before commit 3d6a98457
decided it was okay to leave VM and FSM pages intentionally zero.
Nonetheless, it seems prudent to back-patch. log_newpage_range()
was added in v12 but later back-patched, so this affects all
supported branches.
Matthias van de Meent, per report from Justin Pryzby
Tom Lane [Sat, 15 Apr 2023 16:01:39 +0000 (12:01 -0400)]
Fix assignment to array of domain over composite, redux.
Commit 3e310d837 taught isAssignmentIndirectionExpr() to look through
CoerceToDomain nodes. That's not sufficient, because since commit 04fe805a1 it's been possible for the planner to simplify
CoerceToDomain to RelabelType when the domain has no constraints
to enforce. So we need to look through RelabelType too.
Per bug #17897 from Alexander Lakhin. Although 3e310d837 was
back-patched to v11, it seems sufficient to apply this change
to v12 and later, since 04fe805a1 came in in v12.
doc: PQinitOpenSSL and PQinitSSL are obsolete in OpenSSL 1.1.0+
Starting with OpenSSL 1.1.0 there is no need to call PQinitOpenSSL
or PQinitSSL to avoid duplicate initialization of OpenSSL. Add a
note to the documentation to explain this.
Backpatch to all supported versions as older OpenSSL versions are
equally likely to be used for all branches.
Reported-by: Sebastien Flaesch <sebastien.flaesch@4js.com> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/DBAP191MB12895BFFEC4B5FE0460D0F2FB0459@DBAP191MB1289.EURP191.PROD.OUTLOOK.COM
Backpatch-through: 11, all supported versions
David Rowley [Fri, 14 Apr 2023 04:21:07 +0000 (16:21 +1200)]
Fix incorrect partition pruning logic for boolean partitioned tables
The partition pruning logic assumed that "b IS NOT true" was exactly the
same as "b IS FALSE". This is not the case when considering NULL values.
Fix this so we correctly include any partition which could hold NULL
values for the NOT case.
Additionally, this fixes a bug in the partition pruning code which handles
partitioned tables partitioned like ((NOT boolcol)). This is a seemingly
unlikely schema design, and it was untested and also broken.
Here we add tests for the ((NOT boolcol)) case and insert some actual data
into those tables and verify we do get the correct rows back when running
queries. I've also adjusted the existing boolpart tests to include some
data and verify we get the correct results too.
Both the bugs being fixed here could lead to incorrect query results with
fewer rows being returned than expected. No additional rows could have
been returned accidentally.
In passing, remove needless ternary expression. It's more simple just to
pass !is_not_clause to makeBoolConst(). It makes sense to do this so the
code is consistent with the bug fix in the "else if" condition just below.
David Kimura did submit a patch to fix the first of the issues here, but
that's not what's being committed here.
Reported-by: David Kimura Reviewed-by: Richard Guo, David Kimura
Discussion: https://postgr.es/m/CAHnPFjQ5qxs6J_p+g8=ww7GQvfn71_JE+Tygj0S7RdRci1uwPw@mail.gmail.com
Backpatch-through: 11, all supported versions
Tom Lane [Wed, 12 Apr 2023 14:46:30 +0000 (10:46 -0400)]
Fix parallel-safety marking when moving initplans to another node.
Our policy since commit ab77a5a45 has been that a plan node having
any initplans is automatically not parallel-safe. (This could be
relaxed, but not today.) clean_up_removed_plan_level neglected
this, and could attach initplans to a parallel-safe child plan
node without clearing the plan's parallel-safe flag. That could
lead to "subplan was not initialized" errors at runtime, in case
an initplan referenced another one and only the referencing one
got transmitted to parallel workers.
The fix in clean_up_removed_plan_level is trivial enough.
materialize_finished_plan also moves initplans from one node
to another, but it's okay because it already copies the source
node's parallel_safe flag. The other place that does this kind
of thing is standard_planner's hack to inject a top-level Gather
when debug_parallel_query is active. But that's actually dead
code given that we're correctly enforcing the "initplans aren't
parallel safe" rule, so just replace it with an Assert that
there are no initplans.
Also improve some related comments.
Normally we'd add a regression test case for this sort of bug.
The mistake itself is already reached by existing tests, but there
is accidentally no visible problem. The only known test case that
creates an actual failure seems too indirect and fragile to justify
keeping it as a regression test (not least because it fails to fail
in v11, though the bug is clearly present there too).
Per report from Justin Pryzby. Back-patch to all supported branches.
Michael Paquier [Wed, 12 Apr 2023 00:09:53 +0000 (09:09 +0900)]
Fix detection of unseekable files for fseek() and ftello() with MSVC
Calling fseek() or ftello() on a handle to a non-seeking device such as
a pipe or a communications device is not supported. Unfortunately,
MSVC's flavor of these routines, _fseeki64() and _ftelli64(), do not
return an error when given a pipe as handle. Some of the logic of
pg_dump and restore relies on these routines to check if a handle is
seekable, causing failures when passing the contents of pg_dump to
pg_restore through a pipe, for example.
This commit introduces wrappers for fseeko() and ftello() on MSVC so as
any callers are able to properly detect the cases of non-seekable
handles. This relies mainly on GetFileType(), sharing a bit of code
with the MSVC port for fstat(). The code in charge of getting a file
type is refactored into a new file called win32common.c, shared by
win32stat.c and the new win32fseek.c. It includes the MSVC ports for
fseeko() and ftello().
Like 765f5df, this is backpatched down to 14, where the fstat()
implementation for MSVC is able to understand about files larger than
4GB in size. Using a TAP test for that is proving to be tricky as
IPC::Run handles the pipes by itself, still I have been able to check
the fix manually.
Reported-by: Daniel Watzinger
Author: Juan José Santamaría Flecha, Michael Paquier
Discussion: https://postgr.es/m/CAC+AXB26a4EmxM2suXxPpJaGrqAdxracd7hskLg-zxtPB50h7A@mail.gmail.com
Backpatch-through: 14
Tom Lane [Mon, 10 Apr 2023 19:49:48 +0000 (15:49 -0400)]
Doc: add missed entries in BRIN extensibility tables.
The tables in "71.3. Extensibility" listing the support functions
for bloom and minmax-multi opclasses should include the associated
options function. While this isn't quite as required as the rest,
you need it for full functionality of the opclass.
Back-patch to v14 where these functions were added.
Tom Lane [Mon, 10 Apr 2023 17:09:18 +0000 (13:09 -0400)]
Doc: adjust examples of EXTRACT() output to match current reality.
EXTRACT(EPOCH), EXTRACT(SECOND), and some related cases print more
trailing zeroes than they used to. This behavior change happened
with commit a2da77cdb (Change return type of EXTRACT to numeric),
and it was intentional according to the commit log:
- Return values when extracting fields with possibly fractional
values, such as second and epoch, now have the full scale that the
value has internally (so, for example, '1.000000' instead of just
'1').
It's been like that for two releases now, so while I suggested
changing this back, it's probably better to adjust the documentation
examples.
Per bug #17866 from Евгений Жужнев. Back-patch to v14 where the
change came in.
Stephen Frost [Fri, 7 Apr 2023 23:36:25 +0000 (19:36 -0400)]
For Kerberos testing, disable DNS lookups
Similar to 8dff2f224, this disables DNS lookups by the Kerberos library
to look up the KDC and the realm while the Kerberos tests are running.
In some environments, these lookups can take a long time and end up
timing out and causing tests to fail. Further, since this isn't really
our domain, we shouldn't be sending out these DNS requests during our
tests.
Stephen Frost [Fri, 7 Apr 2023 23:36:25 +0000 (19:36 -0400)]
For Kerberos testing, disable reverse DNS lookup
In our Kerberos test suite, there isn't much need to worry about the
normal canonicalization that Kerberos provides by looking up the reverse
DNS for the IP address connected to, and in some cases it can actively
cause problems (eg: a captive portal wifi where the normally not
resolvable localhost address used ends up being resolved anyway, and
not to the domain we are using for testing, causing the entire
regression test to fail with errors about not being able to get a TGT
for the remote realm for cross-realm trust).
Therefore, disable it by adding rdns = false into the krb5.conf that's
generated for the test.
Reviewed-By: Heikki Linnakangas
Discussion: https://postgr.es/m/Y/QD2zDkDYQA1GQt@tamriel.snowman.net
Tom Lane [Thu, 6 Apr 2023 22:13:49 +0000 (18:13 -0400)]
Stabilize just-added regression test cases.
The tests added by commits 029dea882 et al turn out to produce
different output under -DRANDOMIZE_ALLOCATED_MEMORY. This is
not a bug exactly: that flag causes coerce_type() to invoke
the input function twice when coercing an unknown-type literal
to a specific type. So you get tsqueryin's bleat about an empty
tsquery twice. Revise the test query to avoid that.
Tom Lane [Thu, 6 Apr 2023 19:52:37 +0000 (15:52 -0400)]
Fix ts_headline() edge cases for empty query and empty search text.
tsquery's GETQUERY() macro is only safe to apply to a tsquery
that is known non-empty; otherwise it gives a pointer to garbage.
Before commit 5a617d75d, ts_headline() avoided this pitfall, but
only in a very indirect, nonobvious way. (hlCover could not reach
its TS_execute call, because if the query contains no lexemes
then hlFirstIndex would surely return -1.) After that commit,
it fell into the trap, resulting in weird errors such as
"unrecognized operator" and/or valgrind complaints. In HEAD,
fix this by not calling TS_execute_locations() at all for an
empty query. In the back branches, add a defensive check to
hlCover() --- that's not fixing any live bug, but I judge the
code a bit too fragile as-is.
Also, both mark_hl_fragments() and mark_hl_words() were careless
about the possibility of empty search text: in the cases where
no match has been found, they'd end up telling mark_fragment() to
mark from word indexes 0 to 0 inclusive, even when there is no
word 0. This is harmless since we over-allocated the prs->words
array, but it does annoy valgrind. Fix so that the end index is -1
and thus mark_fragment() will do nothing in such cases.
Bottom line is that this fixes a live bug in HEAD, but in the
back branches it's only getting rid of a valgrind nitpick.
Back-patch anyway.
Tom Lane [Wed, 5 Apr 2023 16:56:30 +0000 (12:56 -0400)]
Fix another issue with ENABLE/DISABLE TRIGGER on partitioned tables.
In v13 and v14, the ENABLE/DISABLE TRIGGER USER variant malfunctioned
on cloned triggers, failing to find the clones because it thought they
were system triggers. Other variants of ENABLE/DISABLE TRIGGER would
improperly apply a superuserness check. Fix by adjusting the is-it-
a-system-trigger check to match reality in those branches. (As far
as I can find, this is the only place that got it wrong.)
There's no such bug in v15/HEAD, because we revised the catalog
representation of system triggers to be what this code was expecting.
However, add the test case to these branches anyway, because this area
is visibly pretty fragile. Also remove an obsoleted comment.
The recent v15/HEAD commit 6949b921d fixed a nearby bug. I now see
that my commit message for that was inaccurate: the behavior of
recursing to clone triggers is older than v15, but it didn't apply
to the case in v13/v14 because in those branches parent partitioned
tables have no pg_trigger entries for foreign-key triggers. But add
the test case from that commit to v13/v14, just to show what is
happening there.
Michael Paquier [Tue, 4 Apr 2023 22:59:49 +0000 (07:59 +0900)]
doc: Add more details about pg_stat_get_xact_blocks_{fetched,hit}
The explanation describing the dependency to system read() calls for
these two functions has been removed in ddfc2d9. And after more
discussion about d69c404, we have concluded that adding more details
makes them easier to understand.
While on it, use the term "block read requests" (maybe found in cache)
rather than "buffers fetched" and "buffer hits".
Per discussion with Melanie Plageman, Kyotaro Horiguchi, Bertrand
Drouvot and myself.
Tom Lane [Fri, 31 Mar 2023 15:18:49 +0000 (11:18 -0400)]
Reject system columns as elements of foreign keys.
Up through v11 it was sensible to use the "oid" system column as
a foreign key column, but since that was removed there's no visible
usefulness in making any of the remaining system columns a foreign
key. Moreover, since the TupleTableSlot rewrites in v12, such cases
actively fail because of implicit assumptions that only user columns
appear in foreign keys. The lack of complaints about that seems
like good evidence that no one is trying to do it. Hence, rather
than trying to repair those assumptions (of which there are at least
two, maybe more), let's just forbid the case up front.
Per this patch, a system column in either the referenced or
referencing side of a foreign key will draw this error; however,
putting one in the referenced side would have failed later anyway,
since we don't allow unique indexes to be made on system columns.
Per bug #17877 from Alexander Lakhin. Back-patch to v12; the
case still appears to work in v11, so we shouldn't break it there.
Tom Lane [Fri, 31 Mar 2023 14:08:40 +0000 (10:08 -0400)]
Ensure acquire_inherited_sample_rows sets its output parameters.
The totalrows/totaldeadrows outputs were left uninitialized in cases
where we find no analyzable child tables of a partitioned table. This
could lead to setting the partitioned table's pg_class.reltuples value
to garbage. It's not clear that that would have any very bad effects
in practice, but fix it anyway because it's making valgrind unhappy.
Reported and diagnosed by Alexander Lakhin (bug #17880).
David Rowley [Thu, 30 Mar 2023 23:13:34 +0000 (12:13 +1300)]
Fix List memory issue in transformColumnDefinition
When calling generateSerialExtraStmts(), we would pass in the
constraint->options. In some cases, generateSerialExtraStmts() would
modify the referenced List to remove elements from it, but doing so is
invalid without assigning the list back to all variables that point to it.
In the particular reported problem case, the List became empty, in which
cases it became NIL, but the passed in constraint->options didn't get to
find out about that and was left pointing to free'd memory.
To fix this, just perform a list_copy() inside generateSerialExtraStmts().
We could just do a list_copy() just before we perform the delete from the
list, however, that seems less robust. Let's make sure the generated
CreateSeqStmt gets a completely different copy of the list to be safe.
Tom Lane [Wed, 29 Mar 2023 15:31:30 +0000 (11:31 -0400)]
Fix dereference of dangling pointer in GiST index buffering build.
gistBuildCallback tried to fetch the size of an index tuple that
might have already been freed by gistProcessEmptyingQueue.
While this seems to usually be harmless in production builds,
in principle it could result in a SIGSEGV, or more likely a bogus
value for indtuplesSize leading to poor page-split decisions later
in the build.
The memory management here is confusing and could stand to be
refactored, but for the moment it seems to be enough to fetch
the tuple size sooner. AFAICT the indtuples[Size] totals aren't
used in between these places; even if they were, the updated
values shouldn't be any worse to use. So just move the
incrementing of the totals up.
It's not very clear why our valgrind-using buildfarm animals
haven't noticed this problem, because the relevant code path
does seem to be exercised according to the code coverage report.
I think the reason that we didn't fix this bug after the first
report is that I'd wanted to try to understand that better.
However, now that it's been re-discovered let's just be pragmatic
and fix it already.
Original report by Alexander Lakhin (bug #16329),
later rediscovered by Egor Chindyaskin (bug #17874).
Patch by Alexander Lakhin (commentary by Pavel Borisov and me).
Back-patch to all supported branches.
Robert Haas [Tue, 28 Mar 2023 20:16:53 +0000 (16:16 -0400)]
amcheck: In verify_heapam, allows tuples with xmin 0.
Commit e88754a1965c0f40a723e6e46d670cacda9e19bd caused that case
to be reported as corruption, but Peter Geoghegan pointed out that
it can legitimately happen in the case of a speculative insertion
that aborts, so we'd better not flag it as corruption after all.
Back-patch to v14, like the commit that introduced the issue.
Tom Lane [Tue, 28 Mar 2023 15:36:50 +0000 (11:36 -0400)]
Fix corner-case planner failure for MERGE.
MERGE planning could fail with "variable not found in subplan target
list" if the target table is partitioned and all its partitions are
excluded at plan time, or in the case where it has no partitions but
used to have some. This happened because distribute_row_identity_vars
thought it didn't need to make the target table's reltarget list
fully valid; but if we generate a join plan then that is required
because the dummy Result node's tlist will be made from the reltarget.
The same logic appears in distribute_row_identity_vars in v14,
but AFAICS the problem is unreachable in that branch for lack of
MERGE. In other updating statements, the target table is always
inner-joined to any other tables, so if the target is known dummy
then the whole plan reduces to dummy, so no join nodes are created.
So I'll refrain from back-patching this code change to v14 for now.
doc: Fix XML_CATALOG_FILES env var for Apple Silicon machines
Homebrew changed the prefix for Apple Silicon based machines, so
our advice for XML_CATALOG_FILES needs to mention both. More info
on the Homebrew change can be found at:
https://github.com/Homebrew/brew/issues/9177
This is backpatch of commits 4c8d65408 and 5a91c7975, the latter
which contained a small fix based on a report from Dagfinn Ilmari
Mannsåker.
Tom Lane [Mon, 27 Mar 2023 19:04:02 +0000 (15:04 -0400)]
Reject attempts to alter composite types used in indexes.
find_composite_type_dependencies() ignored indexes, which is a poor
decision because an expression index could have a stored column of
a composite (or other container) type even when the underlying table
does not. Teach it to detect such cases and error out. We have to
work a bit harder than for other relations because the pg_depend entry
won't identify the specific index column of concern, but it's not much
new code.
This does not address bug #17872's original complaint that dropping
a column in such a type might lead to violations of the uniqueness
property that a unique index is supposed to ensure. That seems of
much less concern to me because it won't lead to crashes.
Per bug #17872 from Alexander Lakhin. Back-patch to all supported
branches.
Tom Lane [Sun, 26 Mar 2023 17:41:06 +0000 (13:41 -0400)]
Fix oversights in array manipulation.
The nested-arrays code path in ExecEvalArrayExpr() used palloc to
allocate the result array, whereas every other array-creating function
has used palloc0 since 18c0b4ecc. This mostly works, but unused bits
past the end of the nulls bitmap may end up undefined. That causes
valgrind complaints with -DWRITE_READ_PARSE_PLAN_TREES, and could
cause planner misbehavior as cited in 18c0b4ecc. There seems no very
good reason why we should strive to avoid palloc0 in just this one case,
so fix it the easy way with s/palloc/palloc0/.
While looking at that I noted that we also failed to check for overflow
of "nbytes" and "nitems" while summing the sizes of the sub-arrays,
potentially allowing a crash due to undersized output allocation.
For "nbytes", follow the policy used by other array-munging code of
checking for overflow after each addition. (As elsewhere, the last
addition of the array's overhead space doesn't need an extra check,
since palloc itself will catch a value between 1Gb and 2Gb.)
For "nitems", there's no very good reason to sum the inputs at all,
since we can perfectly well use ArrayGetNItems' result instead of
ignoring it.
Per discussion of this bug, also remove redundant zeroing of the
nulls bitmap in array_set_element and array_set_slice.
Patch by Alexander Lakhin and myself, per bug #17858 from Alexander
Lakhin; thanks also to Richard Guo. These bugs are a dozen years old,
so back-patch to all supported branches.
Robert Haas [Thu, 23 Mar 2023 19:29:28 +0000 (15:29 -0400)]
amcheck: Fix verify_heapam for tuples where xmin or xmax is 0.
In such cases, get_xid_status() doesn't set its output parameter (the
third argument), so we shouldn't fall through to code which will test
the value of that parameter. There are five existing calls to
get_xid_status(), three of which seem to already handle this case
properly. This commit tries to fix the other two.
If we're checking xmin and find that it is invalid (i.e. 0) just
report that as corruption, similar to what's already done in the
three cases that seem correct. If we're checking xmax and find
that's invalid, that's fine: it just means that the tuple hasn't
been updated or deleted.
Thanks to Andres Freund and valgrind for finding this problem, and
also to Andres for having a look at the patch. This bug seems to go
all the way back to where verify_heapam was first introduced, but
wasn't detected until recently, possibly because of the new test cases
added for update chain verification. Back-patch to v14, where this
code showed up.
Amit Kapila [Thu, 23 Mar 2023 06:16:16 +0000 (11:46 +0530)]
Ignore generated columns during apply of update/delete.
We fail to apply updates and deletes when the REPLICA IDENTITY FULL is
used for the table having generated columns. We didn't use to ignore
generated columns while doing tuple comparison among the tuples from
the publisher and subscriber during apply of updates and deletes.
Author: Onder Kalaci Reviewed-by: Shi yu, Amit Kapila
Backpatch-through: 12
Discussion: https://postgr.es/m/CACawEhVQC9WoofunvXg12aXtbqKnEgWxoRx3+v8q32AWYsdpGg@mail.gmail.com
Andres Freund [Wed, 22 Mar 2023 16:26:23 +0000 (09:26 -0700)]
Fix memory leak and inefficiency in CREATE DATABASE ... STRATEGY WAL_LOG
RelationCopyStorageUsingBuffer() did not free the strategies used to access
the source / target relation. They memory was released at the end of the
transaction, but when using a template database with a lot of relations, the
temporary leak can become big prohibitively big.
RelationCopyStorageUsingBuffer() acquired the buffer for the target relation
with RBM_NORMAL, therefore requiring a read of a block guaranteed to be
zero. Use RBM_ZERO_AND_LOCK instead.
Reviewed-by: Robert Haas <robertmhaas@gmail.com>
Discussion: https://postgr.es/m/20230321070113.o2vqqxogjykwgfrr@awork3.anarazel.de
Backpatch: 15-, where STRATEGY WAL_LOG was introduced
Michael Paquier [Wed, 22 Mar 2023 09:32:02 +0000 (18:32 +0900)]
doc: Add description of some missing monitoring functions
This commit adds some documentation about two monitoring functions:
- pg_stat_get_xact_blocks_fetched()
- pg_stat_get_xact_blocks_hit()
The description of these functions has been removed in ddfc2d9, later
simplified by 5f2b089, assuming that all the functions whose
descriptions were removed are used in system views. Unfortunately, some
of them were are not used in any system views, so they lacked
documentation.
This gap exists in the docs for a long time, so backpatch all the way
down.
Amit Kapila [Tue, 21 Mar 2023 04:10:41 +0000 (09:40 +0530)]
Ignore dropped columns during apply of update/delete.
We fail to apply updates and deletes when the REPLICA IDENTITY FULL is
used for the table having dropped columns. We didn't use to ignore dropped
columns while doing tuple comparison among the tuples from the publisher
and subscriber during apply of updates and deletes.
Author: Onder Kalaci, Shi yu Reviewed-by: Amit Kapila
Discussion: https://postgr.es/m/CACawEhVQC9WoofunvXg12aXtbqKnEgWxoRx3+v8q32AWYsdpGg@mail.gmail.com
Thomas Munro [Tue, 21 Mar 2023 01:29:34 +0000 (14:29 +1300)]
Fix race in parallel hash join batch cleanup, take II.
With unlucky timing and parallel_leader_participation=off (not the
default), PHJ could attempt to access per-batch shared state just as it
was being freed. There was code intended to prevent that by checking
for a cleared pointer, but it was racy. Fix, by introducing an extra
barrier phase. The new phase PHJ_BUILD_RUNNING means that it's safe to
access the per-batch state to find a batch to help with, and
PHJ_BUILD_DONE means that it is too late. The last to detach will free
the array of per-batch state as before, but now it will also atomically
advance the phase, so that late attachers can avoid the hazard. This
mirrors the way per-batch hash tables are freed (see phases
PHJ_BATCH_PROBING and PHJ_BATCH_DONE).
An earlier attempt to fix this (commit 3b8981b6, later reverted) missed
one special case. When the inner side is empty (the "empty inner
optimization), the build barrier would only make it to
PHJ_BUILD_HASHING_INNER phase before workers attempted to detach from
the hashtable. In that case, fast-forward the build barrier to
PHJ_BUILD_RUNNING before proceeding, so that our later assertions hold
and we can still negotiate who is cleaning up.
Revealed by build farm failures, where BarrierAttach() failed a sanity
check assertion, because the memory had been clobbered by dsa_free().
In non-assert builds, the result could be a segmentation fault.
Back-patch to all supported releases.
Author: Thomas Munro <thomas.munro@gmail.com>
Author: Melanie Plageman <melanieplageman@gmail.com> Reported-by: Michael Paquier <michael@paquier.xyz> Reported-by: David Geier <geidav.pg@gmail.com> Tested-by: David Geier <geidav.pg@gmail.com>
Discussion: https://postgr.es/m/20200929061142.GA29096%40paquier.xyz
Tomas Vondra [Mon, 20 Mar 2023 08:51:50 +0000 (09:51 +0100)]
Fix netmask handling in inet_minmax_multi_ops
When calculating distance in brin_minmax_multi_distance_inet(), the
netmask was applied incorrectly. This results in (seemingly) incorrect
ordering of values, triggering an assert.
For builds without asserts this is mostly harmless - we may merge other
ranges, possibly resulting in slightly less efficient index. But it's
still correct and the greedy algorithm doesn't guarantee optimality
anyway.
Backpatch to 14, where minmax-multi indexes were introduced.
Reported by Dmitry Dolgov, investigation and fix by me.
David Rowley [Mon, 20 Mar 2023 00:30:15 +0000 (13:30 +1300)]
Fix memory leak in Memoize cache key evaluation
When probing the Memoize cache to check if the current cache key values
exist in the cache, we perform an evaluation of the expressions making up
the cache key before probing the hash table for those values. This
operation could leak memory as it is possible that the cache key is an
expression which requires allocation of memory, as was the case in bug
17844.
Here we fix this by correctly switching to the per tuple context before
evaluating the cache expressions so that the memory is freed next time the
per tuple context is reset.
Bug: 17844 Reported-by: Alexey Ermakov
Discussion: https://postgr.es/m/17844-d2f6f9e75a622bed@postgresql.org
Backpatch-through: 14, where Memoize was introduced
Tom Lane [Fri, 17 Mar 2023 17:31:40 +0000 (13:31 -0400)]
Fix pg_dump for hash partitioning on enum columns.
Hash partitioning on an enum is problematic because the hash codes are
derived from the OIDs assigned to the enum values, which will almost
certainly be different after a dump-and-reload than they were before.
This means that some rows probably end up in different partitions than
before, causing restore to fail because of partition constraint
violations. (pg_upgrade dodges this problem by using hacks to force
the enum values to keep the same OIDs, but that's not possible nor
desirable for pg_dump.)
Users can work around that by specifying --load-via-partition-root,
but since that's a dump-time not restore-time decision, one might
find out the need for it far too late. Instead, teach pg_dump to
apply that option automatically when dealing with a partitioned
table that has hash-on-enum partitioning.
Also deal with a pre-existing issue for --load-via-partition-root
mode: in a parallel restore, we try to TRUNCATE target tables just
before loading them, in order to enable some backend optimizations.
This is bad when using --load-via-partition-root because (a) we're
likely to suffer deadlocks from restore jobs trying to restore rows
into other partitions than they came from, and (b) if we miss getting
a deadlock we might still lose data due to a TRUNCATE removing rows
from some already-completed restore job.
The fix for this is conceptually simple: just don't TRUNCATE if we're
dealing with a --load-via-partition-root case. The tricky bit is for
pg_restore to identify those cases. In dumps using COPY commands we
can inspect each COPY command to see if it targets the nominal target
table or some ancestor. However, in dumps using INSERT commands it's
pretty impractical to examine the INSERTs in advance. To provide a
solution for that going forward, modify pg_dump to mark TABLE DATA
items that are using --load-via-partition-root with a comment.
(This change also responds to a complaint from Robert Haas that
the dump output for --load-via-partition-root is pretty confusing.)
pg_restore checks for the special comment as well as checking the
COPY command if present. This will fail to identify the combination
of --load-via-partition-root and --inserts in pre-existing dump files,
but that should be a pretty rare case in the field. If it does
happen you will probably get a deadlock failure that you can work
around by not using parallel restore, which is the same as before
this bug fix.
Having done this, there seems no remaining reason for the alarmism
in the pg_dump man page about combining --load-via-partition-root
with parallel restore, so remove that warning.
Patch by me; thanks to Julien Rouhaud for review. Back-patch to
v11 where hash partitioning was introduced.
Andres Freund [Fri, 17 Mar 2023 06:03:31 +0000 (23:03 -0700)]
tests: Prevent syslog activity by slapd, take 2
Unfortunately it turns out that the logfile-only option added in b9f8d1cbad7
is only available in openldap starting in 2.6.
Luckily the option to control the log level (loglevel/-s) have been around for
much longer. As it turns out loglevel/-s only control what goes into syslog,
not what ends up in the file specified with 'logfile' and stderr.
While we currently are specifying 'logfile', nothing ends up in it, as the
option only controls debug messages, and we didn't set a debug level. The
debug level can only be configured on the commandline and also prevents
forking. That'd require larger changes, so this commit doesn't tackle that
issue.
Specify the syslog level when starting slapd using -s, as that allows to
prevent all syslog messages if one uses '0' instead of 'none', while loglevel
doesn't prevent the first message.
David Rowley [Fri, 17 Mar 2023 02:51:00 +0000 (15:51 +1300)]
Fix incorrect logic for determining safe WindowAgg run conditions
The logic added in 9d9c02ccd to determine when a qual can be used as a
WindowClause run condition failed to correctly check for subqueries in the
qual. This was being done correctly for normal subquery qual pushdowns,
it's just that 9d9c02ccd failed to follow the lead on that.
This also fixes various other cases where transforming the qual into a
WindowClause run condition in the subquery should have been disallowed.
Bug: #17826 Reported-by: Anban Company
Discussion: https://postgr.es/m/17826-7d8750952f19a5f5@postgresql.org
Backpatch-through: 15, where 9d9c02ccd was introduced.
Andres Freund [Fri, 17 Mar 2023 00:48:47 +0000 (17:48 -0700)]
tests: Minimize syslog activity by slapd
Until now the tests using slapd spammed syslog for every connection /
query. Use logfile-only to prevent syslog activity. Unfortunately that only
takes effect after logging the first message, but that's still much better
than the prior situation.
Further to commit 6a9229da, checking for NULL is now redundant. An "out
of memory" error would have been thrown already by palloc() and treated
as FATAL, so we can delete a few more lines.
Back-patch to all releases, like those other commits.
Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/4040668.1679013388%40sss.pgh.pa.us
Andres Freund [Thu, 16 Mar 2023 21:08:44 +0000 (14:08 -0700)]
Work around spurious compiler warning in inet operators
gcc 12+ has complaints like the following:
../../../../../pgsql/src/backend/utils/adt/network.c: In function 'inetnot':
../../../../../pgsql/src/backend/utils/adt/network.c:1893:34: warning: writing 1 byte into a region of size 0 [-Wstringop-overflow=]
1893 | pdst[nb] = ~pip[nb];
| ~~~~~~~~~^~~~~~~~~~
../../../../../pgsql/src/include/utils/inet.h:27:23: note: at offset -1 into destination object 'ipaddr' of size 16
27 | unsigned char ipaddr[16]; /* up to 128 bits of address */
| ^~~~~~
../../../../../pgsql/src/include/utils/inet.h:27:23: note: at offset -1 into destination object 'ipaddr' of size 16
This is due to a compiler bug:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104986
It has been a year since the bug has been reported without getting fixed. As
the warnings are verbose and use of gcc 12 is becoming more common, it seems
worth working around the bug. Particularly because a simple reformulation of
the loop condition fixes the issue and isn't any less readable.
Author: Tom Lane <tgl@sss.pgh.pa.us>
Author: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/144536.1648326206@sss.pgh.pa.us
Backpatch: 11-
A comment was left behind claiming that we needed to use malloc() rather
than palloc() because the corresponding free would run in another
thread, but that's not true anymore. Remove that comment. And, with
the reason being gone, we might as well actually use palloc().
Tom Lane [Thu, 16 Mar 2023 20:50:56 +0000 (16:50 -0400)]
Doc: mention CREATE+ATTACH PARTITION with CREATE TABLE...PARTITION OF.
Clarify that ATTACH/DETACH PARTITION can be used to perform partition
maintenance with less locking than straight CREATE TABLE/DROP TABLE.
This was already stated in some places, but not emphasized.
Back-patch to v14 where DETACH PARTITION CONCURRENTLY was added.
(We had lower lock levels for ATTACH PARTITION before that, but
this wording wouldn't apply.)
Justin Pryzby, reviewed by Robert Treat and Jakub Wartak;
a little further wordsmithing by me
Tom Lane [Wed, 15 Mar 2023 15:59:18 +0000 (11:59 -0400)]
Support PlaceHolderVars in MERGE actions.
preprocess_targetlist thought PHVs couldn't appear here.
It was mistaken, as per report from Önder Kalacı.
Surveying other pull_var_clause calls, I noted no similar errors,
but I did notice that qual_is_pushdown_safe's assertion about
!contain_window_function was pointless, because the following
pull_var_clause call would complain about them anyway. In HEAD
only, remove the redundant Assert and improve the commentary.
Michael Paquier [Wed, 15 Mar 2023 03:56:06 +0000 (12:56 +0900)]
Improve WIN32 port of fstat() to detect more file types
The current implementation of _pgfstat64() is ineffective in detecting a
terminal handle or an anonymous named pipe. This commit improves our
port of fstat() to detect more efficiently such cases by relying on
GetFileType(), and returning more correct data when the type found is
either a FILE_TYPE_PIPE (_S_IFIFO) or a FILE_TYPE_CHAR (_S_IFCHR).
This is part of a more global fix to address failures when feeding the
output generated by pg_dump to pg_restore through a pipe, for example,
but not all of it. We are also going to need to do something about
fseek() and ftello() which are not reliable on WIN32 for the same cases
where fstat() was incorrect. Fixing fstat() is independent of the rest,
though, which is why both fixes are handled separately, and this is the
first part of it.
Reported-by: Daniel Watzinger
Author: Daniel Watzinger, Juan José Santamaría Flecha
Discussion: https://postgr.es/m/b1448cd7-871e-20e3-8398-895e2d1d3bf9@gmail.com
Backpatch-through: 14
Thomas Munro [Wed, 15 Mar 2023 00:57:00 +0000 (13:57 +1300)]
Fix fractional vacuum_cost_delay.
Commit 4753ef37 changed vacuum_delay_point() to use the WaitLatch() API,
to fix the problem that vacuum could keep running for a very long time
after the postmaster died.
Unfortunately, that broke commit caf626b2's support for fractional
vacuum_cost_delay, which shipped in PostgreSQL 12. WaitLatch() works in
whole milliseconds.
For now, revert the change from commit 4753ef37, but add an explicit
check for postmaster death. That's an extra system call on systems
other than Linux and FreeBSD, but that overhead doesn't matter much
considering that we willingly went to sleep and woke up again. (In
later work, we might add higher resolution timeouts to the latch API so
that we could do this with our standard programming pattern, but that
wouldn't be back-patched.)
Thomas Munro [Wed, 15 Mar 2023 00:17:18 +0000 (13:17 +1300)]
Fix waitpid() emulation on Windows.
Our waitpid() emulation didn't prevent a PID from being recycled by the
OS before the call to waitpid(). The postmaster could finish up
tracking more than one child process with the same PID, and confuse
them.
Fix, by moving the guts of pgwin32_deadchild_callback() into waitpid(),
so that resources are released synchronously. The process and PID
continue to exist until we close the process handle, which only happens
once we're ready to adjust our book-keeping of running children.
This seems to explain a couple of failures on CI. It had never been
reported before, despite the code being as old as the Windows port.
Perhaps Windows started recycling PIDs more rapidly, or perhaps timing
changes due to commit 7389aad6 made it more likely to break.
Thanks to Alexander Lakhin for analysis and Andres Freund for tracking
down the root cause.
Back-patch to all supported branches.
Reported-by: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/20230208012852.bvkn2am4h4iqjogq%40awork3.anarazel.de
Tom Lane [Tue, 14 Mar 2023 23:17:31 +0000 (19:17 -0400)]
Fix corner case bug in numeric to_char() some more.
The band-aid applied in commit f0bedf3e4 turns out to still need
some work: it made sure we didn't set Np->last_relevant too small
(to the left of the decimal point), but it didn't prevent setting
it too large (off the end of the partially-converted string).
This could result in fetching data beyond the end of the allocated
space, which with very bad luck could cause a SIGSEGV, though
I don't see any hazard of interesting memory disclosure.
Per bug #17839 from Thiago Nunes. The bug's pretty ancient,
so back-patch to all supported versions.
Tom Lane [Tue, 14 Mar 2023 15:10:45 +0000 (11:10 -0400)]
Remove unnecessary code in dependency_is_compatible_expression().
Scanning the expression for compatible Vars isn't really necessary,
because the subsequent match against StatisticExtInfo entries will
eliminate expressions containing other Vars just fine. Moreover,
this code hadn't stopped to think about what to do with
PlaceHolderVars or Aggrefs in the clause; and at least for the PHV
case, that demonstrably leads to failures. Rather than work out
whether it's reasonable to ignore those, let's just remove the
whole stanza.
Per report from Richard Guo. Back-patch to v14 where this code
was added.
Tom Lane [Mon, 13 Mar 2023 19:19:00 +0000 (15:19 -0400)]
Fix JSON error reporting for many cases of erroneous string values.
The majority of error exit cases in json_lex_string() failed to
set lex->token_terminator, causing problems for the error context
reporting code: it would see token_terminator less than token_start
and do something more or less nuts. In v14 and up the end result
could be as bad as a crash in report_json_context(). Older
versions accidentally avoided that fate; but all versions produce
error context lines that are far less useful than intended,
because they'd stop at the end of the prior token instead of
continuing to where the actually-bad input is.
To fix, invent some macros that make it less notationally painful
to do the right thing. Also add documentation about what the
function is actually required to do; and in >= v14, add an assertion
in report_json_context about token_terminator being sufficiently
far advanced.
Per report from Nikolay Shaplov. Back-patch to all supported
versions.
Tom Lane [Mon, 13 Mar 2023 16:40:28 +0000 (12:40 -0400)]
Fix failure to detect some cases of improperly-nested aggregates.
check_agg_arguments_walker() supposed that it needn't descend into
the arguments of a lower-level aggregate function, but this is
just wrong in the presence of multiple levels of sub-select. The
oversight would lead to executor failures on queries that should
be rejected. (Prior to v11, they actually were rejected, thanks
to a "redundant" execution-time check.)
Per bug #17835 from Anban Company. Back-patch to all supported
branches.
Dean Rasheed [Mon, 13 Mar 2023 11:11:10 +0000 (11:11 +0000)]
Fix MERGE command tag for actions blocked by BEFORE ROW triggers.
This ensures that the row count in the command tag for a MERGE is
correctly computed in the case where UPDATEs or DELETEs are skipped
due to a BEFORE ROW trigger returning NULL (the INSERT case was
already handled correctly by ExecMergeNotMatched() calling
ExecInsert()).
Dean Rasheed [Mon, 13 Mar 2023 10:23:42 +0000 (10:23 +0000)]
Fix concurrent update issues with MERGE.
If MERGE attempts an UPDATE or DELETE on a table with BEFORE ROW
triggers, or a cross-partition UPDATE (with or without triggers), and
a concurrent UPDATE or DELETE happens, the merge code would fail.
In some cases this would lead to a crash, while in others it would
cause the wrong merge action to be executed, or no action at all. The
immediate cause of the crash was the trigger code calling
ExecGetUpdateNewTuple() as part of the EPQ mechanism, which fails
because during a merge ri_projectNew is NULL, since merge has its own
per-action projection information, which ExecGetUpdateNewTuple() knows
nothing about.
Fix by arranging for the trigger code to exit early, returning the
TM_Result and TM_FailureData information, if a concurrent modification
is detected, allowing the merge code to do the necessary EPQ handling
in its own way. Similarly, prevent the cross-partition update code
from doing any EPQ processing for a merge, allowing the merge code to
work out what it needs to do.
This leads to a number of simplifications in nodeModifyTable.c. Most
notably, the ModifyTableContext->GetUpdateNewTuple() callback is no
longer needed, and mergeGetUpdateNewTuple() can be deleted, since
there is no longer any requirement for get-update-new-tuple during a
merge. Similarly, ModifyTableContext->cpUpdateRetrySlot is no longer
needed. Thus ExecGetUpdateNewTuple() and the retry_slot handling of
ExecCrossPartitionUpdate() can be restored to how they were in v14,
before the merge code was added, and ExecMergeMatched() no longer
needs any special-case handling for cross-partition updates.
While at it, tidy up ExecUpdateEpilogue() a bit, making it handle
recheckIndexes locally, rather than passing it in as a parameter,
ensuring that it is freed properly. This dates back to when it was
split off from ExecUpdate() to support merge.
Per bug #17809 from Alexander Lakhin, and follow-up investigation of
bug #17792, also from Alexander Lakhin.
Back-patch to v15, where MERGE was introduced, taking care to preserve
backwards-compatibility of the trigger API in v15 for any extensions
that might use it.
Michael Paquier [Mon, 13 Mar 2023 07:36:28 +0000 (16:36 +0900)]
Fix inconsistent error handling for GSS encryption in PQconnectPoll()
The error cases for TLS and GSS encryption were inconsistent. After TLS
fails, the connection is marked as dead and follow-up calls of
PQconnectPoll() would return immediately, but GSS encryption was not
doing that, so the connection would still have been allowed to enter the
GSS handling code. This was handled incorrectly when gssencmode was set
to "require". "prefer" was working correctly, and this could not happen
under "disable" as GSS encryption would not be attempted.
This commit makes the error handling of GSS encryption on par with TLS
portion, fixing the case of gssencmode=require.
Reported-by: Jacob Champion
Author: Michael Paquier Reviewed-by: Jacob Champion, Stephen Frost
Discussion: https://postgr.es/m/23787477-5fe1-a161-6d2a-e459f74c4713@timescale.com
Backpatch-through: 12
Andres Freund [Sat, 11 Mar 2023 22:12:51 +0000 (14:12 -0800)]
amcheck: Fix FullTransactionIdFromXidAndCtx() for xids before epoch 0
64bit xids can't represent xids before epoch 0 (see also be504a3e974). When
FullTransactionIdFromXidAndCtx() was passed such an xid, it'd create a 64bit
xid far into the future. Noticed while adding assertions in the course of
investigating be504a3e974, as amcheck's test create such xids.
To fix the issue, just return FirstNormalFullTransactionId in this case. A
freshly initdb'd cluster already has a newer horizon. The most minimal version
of this would make the messages for some detected corruptions differently
inaccurate. To make those cases accurate, switch
FullTransactionIdFromXidAndCtx() to use the 32bit modulo difference between
xid and nextxid to compute the 64bit xid, yielding sensible "in the future" /
"in the past" answers.
Reviewed-by: Mark Dilger <mark.dilger@enterprisedb.com>
Discussion: https://postgr.es/m/20230108002923.cyoser3ttmt63bfn@awork3.anarazel.de
Backpatch: 14-, where heapam verification was introduced
Andres Freund [Sat, 11 Mar 2023 22:12:51 +0000 (14:12 -0800)]
amcheck: Fix ordering bug in update_cached_xid_range()
The initialization order in update_cached_xid_range() was wrong, calling
FullTransactionIdFromXidAndCtx() before setting
->next_xid. FullTransactionIdFromXidAndCtx() uses ->next_xid.
In most situations this will not cause visible issues, because the next call
to update_cached_xid_range() will use a less wrong ->next_xid. It's rare that
xids advance fast enough for this to be a problem.
Found while adding more asserts to the 64bit xid infrastructure.
Reviewed-by: Mark Dilger <mark.dilger@enterprisedb.com>
Discussion: https://postgr.es/m/20230108002923.cyoser3ttmt63bfn@awork3.anarazel.de
Backpatch: 14-, where heapam verification was introduced
Tom Lane [Sat, 11 Mar 2023 17:15:41 +0000 (12:15 -0500)]
Fix misbehavior in contrib/pg_trgm with an unsatisfiable regex.
If the regex compiler can see that a regex is unsatisfiable
(for example, '$foo') then it may emit an NFA having no arcs.
pg_trgm's packGraph function did the wrong thing in this case;
it would access off the end of a work array, and with bad luck
could produce a corrupted output data structure causing more
problems later. This could end with wrong answers or crashes
in queries using a pg_trgm GIN or GiST index with such a regex.
Fix by not trying to de-duplicate if there aren't at least 2 arcs.
Per bug #17830 from Alexander Lakhin. Back-patch to all supported
branches.
Tom Lane [Fri, 10 Mar 2023 18:52:28 +0000 (13:52 -0500)]
Ensure COPY TO on an RLS-enabled table copies no more than it should.
The COPY documentation is quite clear that "COPY relation TO" copies
rows from only the named table, not any inheritance children it may
have. However, if you enabled row-level security on the table then
this stopped being true, because the code forgot to apply the ONLY
modifier in the "SELECT ... FROM relation" query that it constructs
in order to allow RLS predicates to be attached. Fix that.
Report and patch by Antonin Houska (comment adjustments and test case
by me). Back-patch to all supported branches.
Thomas Munro [Thu, 9 Mar 2023 03:33:24 +0000 (16:33 +1300)]
Fix race in SERIALIZABLE READ ONLY.
Commit bdaabb9b started skipping doomed transactions when building the
list of possible conflicts for SERIALIZABLE READ ONLY. That makes
sense, because doomed transactions won't commit, but a couple of subtle
things broke:
1. If all uncommitted r/w transactions are doomed, a READ ONLY
transaction would arbitrarily not benefit from the safe snapshot
optimization. It would not be taken immediately, and yet no other
transaction would set SXACT_FLAG_RO_SAFE later.
2. In the same circumstances but with DEFERRABLE, GetSafeSnapshot()
would correctly exit its wait loop without sleeping and then take the
optimization in non-assert builds, but assert builds would fail a sanity
check that SXACT_FLAG_RO_SAFE had been set by another transaction.
This is similar to the case for PredXact->WritableSxactCount == 0. We
should opt out immediately if our possibleUnsafeConflicts list is empty
after filtering.
The code to maintain the serializable global xmin is moved down below
the new opt out site, because otherwise we'd have to reverse its effects
before returning.
Back-patch to all supported releases. Bug #17368.
Reported-by: Alexander Lakhin <exclusion@gmail.com>
Discussion: https://postgr.es/m/17116-d6ca217acc180e30%40postgresql.org
Discussion: https://postgr.es/m/20110707212159.GF76634%40csail.mit.edu
Andres Freund [Wed, 8 Mar 2023 05:36:48 +0000 (21:36 -0800)]
Fix corruption due to vacuum_defer_cleanup_age underflowing 64bit xids
When vacuum_defer_cleanup_age is bigger than the current xid, including the
epoch, the subtraction of vacuum_defer_cleanup_age would lead to a wrapped
around xid. While that normally is not a problem, the subsequent conversion to
a 64bit xid results in a 64bit-xid very far into the future. As that xid is
used as a horizon to detect whether rows versions are old enough to be
removed, that allows removal of rows that are still visible (i.e. corruption).
If vacuum_defer_cleanup_age was never changed from the default, there is no
chance of this bug occurring.
This bug was introduced in dc7420c2c92. A lesser version of it exists in
12-13, introduced by fb5344c969a, affecting only GiST.
The 12-13 version of the issue can, in rare cases, lead to pages in a gist
index getting recycled too early, potentially causing index entries to be
found multiple times.
The fix is fairly simple - don't allow vacuum_defer_cleanup_age to retreat
further than FirstNormalTransactionId.
Patches to make similar bugs easier to find, by adding asserts to the 64bit
xid infrastructure, have been proposed, but are not suitable for backpatching.
Currently there are no tests for vacuum_defer_cleanup_age. A patch introducing
infrastructure to make writing a test easier has been posted to the list.
Reported-by: Michail Nikolaev <michail.nikolaev@gmail.com> Reviewed-by: Matthias van de Meent <boekewurm+postgres@gmail.com>
Author: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/20230108002923.cyoser3ttmt63bfn@awork3.anarazel.de
Backpatch: 12-, but impact/fix is smaller for 12-13
Tom Lane [Tue, 7 Mar 2023 23:21:37 +0000 (18:21 -0500)]
Fix more bugs caused by adding columns to the end of a view.
If a view is defined atop another view, and then CREATE OR REPLACE
VIEW is used to add columns to the lower view, then when the upper
view's referencing RTE is expanded by ApplyRetrieveRule we will have
a subquery RTE with fewer eref->colnames than output columns. This
confuses various code that assumes those lists are always in sync,
as they are in plain parser output.
We have seen such problems before (cf commit d5b760ecb), and now
I think the time has come to do what was speculated about in that
commit: let's make ApplyRetrieveRule synthesize some column names to
preserve the invariant that holds in parser output. Otherwise we'll
be chasing this class of bugs indefinitely. Moreover, it appears from
testing that this actually gives us better results in the test case d5b760ecb added, and likely in other corner cases that we lack
coverage for.
In HEAD, I replaced d5b760ecb's hack to make expandRTE exit early with
an elog(ERROR) call, since the case is now presumably unreachable.
But it seems like changing that in back branches would bring more risk
than benefit, so there I just updated the comment.
Per bug #17811 from Alexander Lakhin. Back-patch to all supported
branches.
Tom Lane [Mon, 6 Mar 2023 23:31:16 +0000 (18:31 -0500)]
Fix some more cases of missed GENERATED-column updates.
If UPDATE is forced to retry after an EvalPlanQual check, it neglected
to repeat GENERATED-column computations, even though those might well
have changed since we're dealing with a different tuple than before.
Fixing this is mostly a matter of looping back a bit further when
we retry. In v15 and HEAD that's most easily done by altering the API
of ExecUpdateAct so that it includes computing GENERATED expressions.
Also, if an UPDATE in a partitioned table turns into a cross-partition
INSERT operation, we failed to recompute GENERATED columns. That's a
bug since 8bf6ec3ba allowed partitions to have different generation
expressions; although it seems to have no ill effects before that.
Fixing this is messier because we can now have situations where the same
query needs both the UPDATE-aligned set of GENERATED columns and the
INSERT-aligned set, and it's unclear which set will be generated first
(else we could hack things by forcing the INSERT-aligned set to be
generated, which is indeed how fe9e658f4 made it work for MERGE).
The best fix seems to be to build and store separate sets of expressions
for the INSERT and UPDATE cases. That would create ABI issues in the
back branches, but so far it seems we can leave this alone in the back
branches.
Per bug #17823 from Hisahiro Kauchi. The first part of this affects all
branches back to v12 where GENERATED columns were added.
Robert Haas [Thu, 2 Feb 2023 17:04:16 +0000 (12:04 -0500)]
In basebackup.c, perform end-of-file test after checksum validation.
We read blocks of data from files that we're backing up in chunks,
some multiple of BLCKSZ for each read. If checksum verification fails,
we then try rereading just the one block for which validation failed.
If that block happened to be the first block of the chunk, and if
the file was concurrently truncated to remove that block, then we'd
reach a call to bbsink_archive_contents() with a buffer length of 0.
That causes an assertion failure.
As far as I can see, there are no particularly bad consequences if
this happens in a non-assert build, and it's pretty unlikely to happen
in the first place because it requires a series of somewhat unlikely
things to happen in very quick succession. However, assertion failures
are bad, so rearrange the code to avoid that possibility.
Thomas Munro [Mon, 6 Mar 2023 02:07:15 +0000 (15:07 +1300)]
Fix assert failures in parallel SERIALIZABLE READ ONLY.
1. Make sure that we don't decrement SxactGlobalXminCount twice when
the SXACT_FLAG_RO_SAFE optimization is reached in a parallel query.
This could trigger a sanity check failure in assert builds. Non-assert
builds recompute the count in SetNewSxactGlobalXmin(), so the problem
was hidden, explaining the lack of field reports. Add a new isolation
test to exercise that case.
2. Remove an assertion that the DOOMED flag can't be set on a partially
released SERIALIZABLEXACT. Instead, ignore the flag (our transaction
was already determined to be read-only safe, and DOOMED is in fact set
during partial release, and there was already an assertion that it
wasn't set sooner). Improve an existing isolation test so that it
reaches that case (previously it wasn't quite testing what it was
supposed to be testing; see discussion).
Back-patch to 12. Bug #17116. Defects in commit 47a338cf.
Reported-by: Alexander Lakhin <exclusion@gmail.com>
Discussion: https://postgr.es/m/17116-d6ca217acc180e30%40postgresql.org
Tom Lane [Sat, 4 Mar 2023 18:32:35 +0000 (13:32 -0500)]
Avoid failure when altering state of partitioned foreign-key triggers.
Beginning in v15, if you apply ALTER TABLE ENABLE/DISABLE TRIGGER to
a partitioned table, it also affects the partitions' cloned versions
of the affected trigger(s). The initial implementation of this
located the clones by name, but that fails on foreign-key triggers
which have names incorporating their own OIDs. We can fix that, and
also make the behavior more bulletproof in the face of user-initiated
trigger renames, by identifying the cloned triggers by tgparentid.
Following the lead of earlier commits in this area, I took care not
to break ABI in the v15 branch, even though I rather doubt there
are any external callers of EnableDisableTrigger.
While here, update the documentation, which was not touched when
the semantics were changed.
Per bug #17817 from Alan Hodgson. Back-patch to v15; older versions
do not have this behavior.
Michael Paquier [Thu, 2 Mar 2023 05:03:08 +0000 (14:03 +0900)]
pageinspect: Fix crash with gist_page_items()
Attempting to use this function with a raw page not coming from a GiST
index would cause a crash, as it was missing the same sanity checks as
gist_page_items_bytea(). This slightly refactors the code so as all the
basic validation checks for GiST pages are done in a single routine,
in the same fashion as the pageinspect functions for hash and BRIN.
This fixes an issue similar to 076f4d9. A test is added to stress for
this case. While on it, I have added a similar test for
brin_page_items() with a combination make of a valid GiST index and a
raw btree page. This one was already protected, but it was not tested.
Tom Lane [Wed, 1 Mar 2023 16:30:17 +0000 (11:30 -0500)]
Avoid fetching one past the end of translate()'s "to" parameter.
This is usually harmless, but if you were very unlucky it could
provoke a segfault due to the "to" string being right up against
the end of memory. Found via valgrind testing (so we might've
found it earlier, except that our regression tests lacked any
exercise of translate()'s deletion feature).
Fix by switching the order of the test-for-end-of-string and
advance-pointer steps. While here, compute "to_ptr + tolen"
just once. (Smarter compilers might figure that out for
themselves, but let's just make sure.)
Tom Lane [Tue, 28 Feb 2023 01:27:48 +0000 (20:27 -0500)]
Drop test view when done with it.
The view just added by commit 53fe7e6cb decompiles differently
in v15 than HEAD (presumably as a consequence of 47bb9db75).
That causes failures in cross-version upgrade testing.
We could teach AdjustUpgrade.pm to compensate for that, but it
seems less painful to just drop the view after we're done with it.
Tom Lane [Mon, 27 Feb 2023 21:29:51 +0000 (16:29 -0500)]
Harden postgres_fdw tests against unexpected cache flushes.
postgres_fdw will close its remote session if an sinval cache reset
occurs, since it's possible that that means some FDW parameters
changed. We had two tests that were trying to ensure that the
session remains alive by setting debug_discard_caches = 0; but
that's not sufficient. Even though the tests seem stable enough
in the buildfarm, they flap a lot under CI.
In the first test, which is checking the ability to recover from
a lost connection, we can stabilize the results by just not
caring whether pg_terminate_backend() finds a victim backend.
If a reset did happen, there won't be a session to terminate
anymore, but the test can proceed anyway. (Arguably, we are
then not testing the unintentional-disconnect case, but as long
as that scenario is exercised in most runs I think it's fine;
testing the reset-driven case is of value too.)
In the second test, which is trying to verify the application_name
displayed in pg_stat_activity by a remote session, we had a race
condition in that the remote session might go away before we can
fetch its pg_stat_activity entry. We can close that race and make
the test more certainly test what it intends to by arranging things
so that the remote session itself fetches its pg_stat_activity entry
(based on PID rather than a somewhat-circular assumption about the
application name).
Both tests now demonstrably pass under debug_discard_caches = 1,
so we can remove that hack.
Andrew Dunstan [Sun, 26 Feb 2023 11:48:41 +0000 (06:48 -0500)]
Don't force SQL_ASCII/no-locale for installcheck in vcregress.pl
It's been this way for a very long time, but it appears to have been
masking an issue that only manifests with different settings. Therefore,
run the tests in the installation's default encoding/locale.
Dean Rasheed [Sun, 26 Feb 2023 09:04:04 +0000 (09:04 +0000)]
Doc: Miscellaneous doc updates for MERGE.
Update a few places in the documentation that should mention MERGE
among the list of applicable commands. In a couple of places, a
slightly more detailed description of what happens for MERGE seems
appropriate.
Tom Lane [Sat, 25 Feb 2023 19:44:14 +0000 (14:44 -0500)]
Fix MULTIEXPR_SUBLINK with partitioned target tables, yet again.
We already tried to fix this in commits 3f7323cbb et al (and follow-on
fixes), but now it emerges that there are still unfixed cases;
moreover, these cases affect all branches not only pre-v14. I thought
we had eliminated all cases of making multiple clones of an UPDATE's
target list when we nuked inheritance_planner. But it turns out we
still do that in some partitioned-UPDATE cases, notably including
INSERT ... ON CONFLICT UPDATE, because ExecInitPartitionInfo thinks
it's okay to clone and modify the parent's targetlist.
This fix is based on a suggestion from Andres Freund: let's stop
abusing the ParamExecData.execPlan mechanism, which was only ever
meant to handle initplans, and instead solve the execution timing
problem by having the expression compiler move MULTIEXPR_SUBLINK steps
to the front of their expression step lists. This is feasible because
(a) all branches still in support compile the entire targetlist of
an UPDATE into a single ExprState, and (b) we know that all
MULTIEXPR_SUBLINKs do need to be evaluated --- none could be buried
inside a CASE, for example. There is a minor semantics change
concerning the order of execution of the MULTIEXPR's subquery versus
other parts of the parent targetlist, but that seems like something
we can get away with. By doing that, we no longer need to worry
about whether different clones of a MULTIEXPR_SUBLINK share output
Params; their usage of that data structure won't overlap.
Per bug #17800 from Alexander Lakhin. Back-patch to all supported
branches. In v13 and earlier, we can revert 3f7323cbb and follow-on
fixes; however, I chose to keep the SubPlan.subLinkId field added
in ccbb54c72. We don't need that anymore in the core code, but it's
cheap enough to fill, and removing a plan node field in a minor
release seems like it'd be asking for trouble.
Dean Rasheed [Sat, 25 Feb 2023 14:43:57 +0000 (14:43 +0000)]
Fix mishandling of OLD/NEW references in subqueries in rule actions.
If a rule action contains a subquery that refers to columns from OLD
or NEW, then those are really lateral references, and the planner will
complain if it sees such things in a subquery that isn't marked as
lateral. However, at rule-definition time, the user isn't required to
mark the subquery with LATERAL, and so it can fail when the rule is
used.
Fix this by marking such subqueries as lateral in the rewriter, at the
point where they're used.
Dean Rasheed and Tom Lane, per report from Alexander Lakhin.
Back-patch to all supported branches.
Tom Lane [Thu, 23 Feb 2023 20:40:28 +0000 (15:40 -0500)]
Don't repeatedly register cache callbacks in pgoutput plugin.
Multiple cycles of starting up and shutting down the plugin within a
single session would eventually lead to "out of relcache_callback_list
slots", because pgoutput_startup blindly re-registered its cache
callbacks each time. Fix it to register them only once, as all other
users of cache callbacks already take care to do.
This has been broken all along, so back-patch to all supported branches.
Dean Rasheed [Thu, 23 Feb 2023 10:54:51 +0000 (10:54 +0000)]
Fix multi-row DEFAULT handling for INSERT ... SELECT rules.
Given an updatable view with a DO ALSO INSERT ... SELECT rule, a
multi-row INSERT ... VALUES query on the view fails if the VALUES list
contains any DEFAULTs that are not replaced by view defaults. This
manifests as an "unrecognized node type" error, or an Assert failure,
in an assert-enabled build.
The reason is that when RewriteQuery() attempts to replace the
remaining DEFAULT items with NULLs in any product queries, using
rewriteValuesRTEToNulls(), it assumes that the VALUES RTE is located
at the same rangetable index in each product query. However, if the
product query is an INSERT ... SELECT, then the VALUES RTE is actually
in the SELECT part of that query (at the same index), rather than the
top-level product query itself.
Fix, by descending to the SELECT in such cases. Note that we can't
simply use getInsertSelectQuery() for this, since that expects to be
given a raw rule action with OLD and NEW placeholder entries, so we
duplicate its logic instead.
While at it, beef up the checks in getInsertSelectQuery() by checking
that the jointree->fromlist node is indeed a RangeTblRef, and that the
RTE it points to has rtekind == RTE_SUBQUERY.
Per bug #17803, from Alexander Lakhin. Back-patch to all supported
branches.
Tomas Vondra [Wed, 22 Feb 2023 14:24:09 +0000 (15:24 +0100)]
Fix snapshot handling in logicalmsg_decode
Whe decoding a transactional logical message, logicalmsg_decode called
SnapBuildGetOrBuildSnapshot. But we may not have a consistent snapshot
yet at that point. We don't actually need the snapshot in this case
(during replay we'll have the snapshot from the transaction), so in
practice this is harmless. But in assert-enabled build this crashes.
Fixed by requesting the snapshot only in non-transactional case, where
we are guaranteed to have SNAPBUILD_CONSISTENT.
Backpatch to 11. The issue exists since 9.6.
Backpatch-through: 11 Reviewed-by: Andres Freund
Discussion: https://postgr.es/m/84d60912-6eab-9b84-5de3-41765a5449e8@enterprisedb.com
Dean Rasheed [Wed, 22 Feb 2023 13:24:51 +0000 (13:24 +0000)]
Add missing support for the latest SPI status codes.
SPI_result_code_string() was missing support for SPI_OK_TD_REGISTER,
and in v15 and later, it was missing support for SPI_OK_MERGE, as was
pltcl_process_SPI_result().
The last of those would trigger an error if a MERGE was executed from
PL/Tcl. The others seem fairly innocuous, but worth fixing.
Back-patch to all supported branches. Before v15, this is just adding
SPI_OK_TD_REGISTER to SPI_result_code_string(), which is unlikely to
be seen by anyone, but seems worth doing for completeness.
Dean Rasheed [Wed, 22 Feb 2023 10:54:57 +0000 (10:54 +0000)]
Fix Assert failure for MERGE into a partitioned table with RLS.
In ExecInitPartitionInfo(), the Assert when building the WITH CHECK
OPTION list for the new partition assumed that the command would be an
INSERT or UPDATE, but it can also be a MERGE. This can be triggered by
a MERGE into a partitioned table with RLS checks to enforce.
Fix, and back-patch to v15, where MERGE was introduced.
Dean Rasheed [Wed, 22 Feb 2023 09:41:28 +0000 (09:41 +0000)]
Fix MERGE command tag for cross-partition updates.
This ensures that the row count in the command tag for a MERGE is
correctly computed. Previously, if MERGE updated a partitioned table,
the row count would be incorrect if any row was moved to a different
partition, since such updates were counted twice.
Michael Paquier [Wed, 22 Feb 2023 01:14:56 +0000 (10:14 +0900)]
Fix corruption of templates after CREATE DATABASE .. STRATEGY WAL_LOG
WAL_LOG does a scan of the template's pg_class to determine the set of
relations that need to be copied from a template database to the new
one. However, as coded in 9c08aea, this copy strategy would load the
pages of pg_class without considering it as a permanent relation,
causing the loaded pages to never be flushed when they should. Any
modification of the template's pg_class, mostly through DDLs, would then
be missed, causing corruptions.
STRATEGY = WAL_LOG is the default over FILE_COPY since it has been
introduced, so any changes done to pg_class on a database template would
be gone. Updates of database templates should be a rare thing, so the
impact of this bug should be hopefully limited. The pre-14 default
strategy FILE_COPY is safe, and can be used as a workaround.
Ryo Matsumura has found and analyzed the issue, and Nathan has written a
test able to reproduce the failure (with few tweaks from me).
Backpatch down to 15, where STRATEGY = WAL_LOG has been introduced.
Tom Lane [Tue, 21 Feb 2023 23:47:46 +0000 (18:47 -0500)]
Fix erroneous Valgrind markings in AllocSetRealloc.
If asked to decrease the size of a large (>8K) palloc chunk,
AllocSetRealloc could improperly change the Valgrind state of memory
beyond the new end of the chunk: it would mark data UNDEFINED as far
as the old end of the chunk after having done the realloc(3) call,
thus tromping on the state of memory that no longer belongs to it.
One would normally expect that memory to now be marked NOACCESS,
so that this mislabeling might prevent detection of later errors.
If realloc() had chosen to move the chunk someplace else (unlikely,
but well within its rights) we could also mismark perfectly-valid
DEFINED data as UNDEFINED, causing false-positive valgrind reports
later. Also, any malloc bookkeeping data placed within this area
might now be wrongly marked, causing additional problems.
Fix by replacing relevant uses of "oldsize" with "Min(size, oldsize)".
It's sufficient to mark as far as "size" when that's smaller, because
whatever remains in the new chunk size will be marked NOACCESS below,
and we expect realloc() to have taken care of marking the memory
beyond the new official end of the chunk.
While we're here, also rename the function's "oldsize" variable
to "oldchksize" to more clearly explain what it actually holds,
namely the distance to the end of the chunk (that is, requested size
plus trailing padding). This is more consistent with the use of
"size" and "chksize" to hold the new requested size and chunk size.
Add a new variable "oldsize" in the one stanza where we're actually
talking about the old requested size.
Oversight in commit c477f3e44. Back-patch to all supported branches,
as that was, just in case anybody wants to do valgrind testing on back
branches.