Affected test queries have been testing the wrong thing since their
introduction in commit 4c1383efd132e4f532213c8a8cc63a455f55e344.
Back-patch to 9.3 (all supported versions).
Document security implications of qualified names.
Commit 5770172cb0c9df9e6ce27c507b449557e5b45124 documented secure schema
usage, and that advice suffices for using unqualified names securely.
Document, in typeconv-func primarily, the additional issues that arise
with qualified names. Back-patch to 9.3 (all supported versions).
Bruce Momjian [Sat, 28 Jul 2018 19:01:55 +0000 (15:01 -0400)]
pg_upgrade: check for clean server shutdowns
Previously pg_upgrade checked for the pid file and started/stopped the
server to force a clean shutdown. However, "pg_ctl -m immediate"
removes the pid file but doesn't do a clean shutdown, so check
pg_controldata for a clean shutdown too.
Diagnosed-by: Vimalraj A
Discussion: https://postgr.es/m/CAFKBAK5e4Q-oTUuPPJ56EU_d2Rzodq6GWKS3ncAk3xo7hAsOZg@mail.gmail.com
Tom Lane [Sat, 21 Jul 2018 19:40:52 +0000 (15:40 -0400)]
Further portability hacking in pg_upgrade's test script.
I blew the dust off a Bourne shell (file date 1996, yea verily) and
tried to run test.sh with it. It mostly worked, but I found that the
temp-directory creation code introduced by commit be76a6d39 was not
compatible, for a couple of reasons: this shell thinks "set -e" should
force an exit if a command within backticks fails, and it also thinks code
within braces should be executed by a sub-shell, meaning that variable
settings don't propagate back up to the parent shell. In view of Victor
Wagner's report that Solaris is still using pre-POSIX shells, seems like
we oughta make this case work. It's not like the code is any less
idiomatic this way; the prior coding technique appeared nowhere else.
(There is a remaining bash-ism here, which is that $RANDOM doesn't do
what the code hopes in non-bash shells. But the use of $$ elsewhere in
that path should be enough to ensure uniqueness and some amount of
randomness, so I think it's okay as-is.)
Back-patch to all supported branches, as the previous commit was.
Tom Lane [Fri, 13 Jul 2018 22:45:30 +0000 (18:45 -0400)]
Fix crash in contrib/ltree's lca() function for empty input array.
lca_inner() wasn't prepared for the possibility of getting no inputs.
Fix that, and make some cosmetic improvements to the code while at it.
Also, I thought the documentation of this function as returning the
"longest common prefix" of the paths was entirely misleading; it really
returns a path one shorter than the longest common prefix, for the typical
definition of "prefix". Don't use that term in the docs, and adjust the
examples to clarify what really happens.
This has been broken since its beginning, so back-patch to all supported
branches.
Per report from Hailong Li. Thanks to Pierre Ducroquet for diagnosing
and for the initial patch, though I whacked it around some and added
test cases.
Tom Lane [Fri, 13 Jul 2018 15:52:50 +0000 (11:52 -0400)]
Fix inadequate buffer locking in FSM and VM page re-initialization.
When reading an existing FSM or VM page that was found to be corrupt by the
buffer manager, the code applied PageInit() to reinitialize the page, but
did so without any locking. There is thus a hazard that two backends might
concurrently do PageInit, which in itself would still be OK, but the slower
one might then zero over subsequent data changes applied by the faster one.
Even that is unlikely to be fatal; but it's not desirable, so add locking
to prevent it.
This does not add any locking overhead in the normal code path where the
page is OK. It's not immediately obvious that that's safe, but I believe
it is, for reasons explained in the added comments.
Problem noted by R P Asim. It's been like this for a long time, so
back-patch to all supported branches.
Tom Lane [Thu, 12 Jul 2018 16:28:43 +0000 (12:28 -0400)]
Doc: minor improvement in pl/pgsql FETCH/MOVE documentation.
Explain that you can use any integer expression for the "count" in
pl/pgsql's versions of FETCH/MOVE, unlike the SQL versions which only
allow a constant.
Remove the duplicate version of this para under MOVE. I don't see
a good reason to maintain two identical paras when we just said that
MOVE works exactly like FETCH.
Tom Lane [Mon, 9 Jul 2018 23:26:19 +0000 (19:26 -0400)]
Avoid emitting a bogus WAL record when recycling an all-zero btree page.
Commit fafa374f2 caused _bt_getbuf() to possibly emit a WAL record for
a page that it was about to recycle. However, it failed to distinguish
all-zero pages from dead pages, which is important because only the
latter have valid btpo.xact values, or indeed any special space at all.
Recycling an all-zero page with XLogStandbyInfoActive() enabled therefore
led to an Assert failure, or to emission of a WAL record containing a
bogus cutoff XID, which might lead to unnecessary query cancellations
on hot standby servers.
Per reports from Antonin Houska and 自己. Amit Kapila was first to
propose this fix, and Robert Haas, myself, and Kyotaro Horiguchi
reviewed it at various times.
This is an old bug, so back-patch to all supported branches.
Tom Lane [Mon, 9 Jul 2018 21:23:32 +0000 (17:23 -0400)]
Prevent accidental linking of system-supplied copies of libpq.so etc.
Back-patch commit dddfc4cb2, which broke LDFLAGS and related Makefile
variables into two parts, one for within-build-tree library references and
one for external libraries, to ensure that the order of -L flags has all
of the former before all of the latter. This turns out to fix a problem
recently noted on buildfarm member peripatus, that we attempted to
incorporate code from libpgport.a into a shared library. That will fail on
platforms that are sticky about putting non-PIC code into shared libraries.
(It's quite surprising we hadn't seen such failures before, since the code
in question has been like that for a long time.)
I think that peripatus' problem could have been fixed with just a subset
of this patch; but since the previous issue of accidentally linking to the
wrong copy of a Postgres shlib seems likely to bite people in the field,
let's just back-patch the whole change. Now that commit dddfc4cb2 has
survived some beta testing, I'm less afraid to back-patch it than I was
at the time.
This also fixes undesired inclusion of "-DFRONTEND" in pg_config's CPPFLAGS
output (in 9.6 and up) and undesired inclusion of "-L../../src/common" in
its LDFLAGS output (in all supported branches).
Back-patch to v10 and older branches; this is already in v11.
Michael Paquier [Thu, 5 Jul 2018 01:48:03 +0000 (10:48 +0900)]
Prevent references to invalid relation pages after fresh promotion
If a standby crashes after promotion before having completed its first
post-recovery checkpoint, then the minimal recovery point which marks
the LSN position where the cluster is able to reach consistency may be
set to a position older than the first end-of-recovery checkpoint while
all the WAL available should be replayed. This leads to the instance
thinking that it contains inconsistent pages, causing a PANIC and a hard
instance crash even if all the WAL available has not been replayed for
certain sets of records replayed. When in crash recovery,
minRecoveryPoint is expected to always be set to InvalidXLogRecPtr,
which forces the recovery to replay all the WAL available, so this
commit makes sure that the local copy of minRecoveryPoint from the
control file is initialized properly and stays as it is while crash
recovery is performed. Once switching to archive recovery or if crash
recovery finishes, then the local copy minRecoveryPoint can be safely
updated.
Pavan Deolasee has reported and diagnosed the failure in the first
place, and the base fix idea to rely on the local copy of
minRecoveryPoint comes from Kyotaro Horiguchi, which has been expanded
into a full-fledged patch by me. The test included in this commit has
been written by Álvaro Herrera and Pavan Deolasee, which I have modified
to make it faster and more reliable with sleep phases.
Backpatch down to all supported versions where the bug appears, aka 9.3
which is where the end-of-recovery checkpoint is not run by the startup
process anymore. The test gets easily supported down to 10, still it
has been tested on all branches.
Improve the performance of relation deletes during recovery.
When multiple relations are deleted at the same transaction,
the files of those relations are deleted by one call to smgrdounlinkall(),
which leads to scan whole shared_buffers only one time. OTOH,
previously, during recovery, smgrdounlink() (not smgrdounlinkall()) was
called for each file to delete, which led to scan shared_buffers
multiple times. Obviously this could cause to increase the WAL replay
time very much especially when shared_buffers was huge.
To alleviate this situation, this commit changes the recovery so that
it also calls smgrdounlinkall() only one time to delete multiple
relation files.
This is just fix for oversight of commit 279628a0a7, not new feature.
So, per discussion on pgsql-hackers, we concluded to backpatch this
to all supported versions.
Author: Fujii Masao Reviewed-by: Michael Paquier, Andres Freund, Thomas Munro, Kyotaro Horiguchi, Takayuki Tsunakawa
Discussion: https://postgr.es/m/CAHGQGwHVQkdfDqtvGVkty+19cQakAydXn1etGND3X0PHbZ3+6w@mail.gmail.com
When these programs call pg_catalog.set_config, they need to check for
PGRES_TUPLES_OK instead of PGRES_COMMAND_OK. Fix for 5770172cb0c9df9e6ce27c507b449557e5b45124.
Michael Paquier [Fri, 29 Jun 2018 13:18:24 +0000 (22:18 +0900)]
Replace search.cpan.org with metacpan.org
search.cpan.org has been EOL'd, with metacpan.org being the official
replacement to which URLs now redirect. Update links to match the new
URL. Also update links to CPAN to use https as it will redirect from
http.
Author: Daniel Gustafsson
Discussion: https://postgr.es/m/B74C0219-6BA9-46E1-A524-5B9E8CD3BDB3@yesql.se
Fujii Masao [Tue, 26 Jun 2018 15:45:21 +0000 (00:45 +0900)]
Fix documentation bug related to backup history file.
The backup history file has been no longer necessary for recovery
since the version 9.0. It's now basically just for informational purpose.
But previously the documentations still described that a recovery
requests the backup history file to proceed. The commit fixes this
documentation bug.
Thomas Munro [Mon, 18 Jun 2018 06:33:53 +0000 (18:33 +1200)]
Add PGTYPESchar_free() to avoid cross-module problems on Windows.
On Windows, it is sometimes important for corresponding malloc() and
free() calls to be made from the same DLL, since some build options can
result in multiple allocators being active at the same time. For that
reason we already provided PQfreemem(). This commit adds a similar
function for freeing string results allocated by the pgtypes library.
Thomas Munro [Tue, 26 Jun 2018 06:23:17 +0000 (18:23 +1200)]
Move RecoveryLockList into a hash table.
Standbys frequently need to release all locks held by a given xid.
Instead of searching one big list linearly, let's create one list
per xid and put them in a hash table, so we can find what we need
in O(1) time.
Earlier analysis and a prototype were done by David Rowley, though
this isn't his patch.
Back-patch all the way.
Author: Thomas Munro Diagnosed-by: David Rowley, Andres Freund Reviewed-by: Andres Freund, Tom Lane, Robert Haas
Discussion: https://postgr.es/m/CAEepm%3D1mL0KiQ2KJ4yuPpLGX94a4Ns_W6TL4EGRouxWibu56pA%40mail.gmail.com
Discussion: https://postgr.es/m/CAKJS1f9vJ841HY%3DwonnLVbfkTWGYWdPN72VMxnArcGCjF3SywA%40mail.gmail.com
Michael Paquier [Mon, 25 Jun 2018 01:30:59 +0000 (10:30 +0900)]
Address set of issues with errno handling
System calls mixed up in error code paths are causing two issues which
several code paths have not correctly handled:
1) For write() calls, sometimes the system may return less bytes than
what has been written without errno being set. Some paths were careful
enough to consider that case, and assumed that errno should be set to
ENOSPC, other calls missed that.
2) errno generated by a system call is overwritten by other system calls
which may succeed once an error code path is taken, causing what is
reported to the user to be incorrect.
This patch uses the brute-force approach of correcting all those code
paths. Some refactoring could happen in the future, but this is let as
future work, which is not targeted for back-branches anyway.
Author: Michael Paquier Reviewed-by: Ashutosh Sharma
Discussion: https://postgr.es/m/20180622061535.GD5215@paquier.xyz
Tom Lane [Sat, 16 Jun 2018 19:34:07 +0000 (15:34 -0400)]
Use -Wno-format-truncation and -Wno-stringop-truncation, if available.
gcc 8 has started emitting some warnings that are largely useless for
our purposes, particularly since they complain about code following
the project-standard coding convention that path names are assumed
to be shorter than MAXPGPATH. Even if we make the effort to remove
that assumption in some future release, the changes wouldn't get
back-patched. Hence, just suppress these warnings, on compilers that
have these switches.
Tom Lane [Sat, 16 Jun 2018 18:58:11 +0000 (14:58 -0400)]
Avoid unnecessary use of strncpy in a couple of places in ecpg.
Use of strncpy with a length limit based on the source, rather than
the destination, is non-idiomatic and draws warnings from gcc 8.
Replace with memcpy, which does exactly the same thing in these cases,
but with less chance for confusion.
Tom Lane [Sat, 16 Jun 2018 18:45:47 +0000 (14:45 -0400)]
Use snprintf not sprintf in pg_waldump's timestamptz_to_str.
This could only cause an issue if strftime returned a ridiculously
long timezone name, which seems unlikely; and it wouldn't qualify
as a security problem even then, since pg_waldump (nee pg_xlogdump)
is a debug tool not part of the server. But gcc 8 has started issuing
warnings about it, so let's use snprintf and be safe.
Andres Freund [Tue, 12 Jun 2018 18:13:22 +0000 (11:13 -0700)]
Fix bugs in vacuum of shared rels, by keeping their relcache entries current.
When vacuum processes a relation it uses the corresponding relcache
entry's relfrozenxid / relminmxid as a cutoff for when to remove
tuples etc. Unfortunately for nailed relations (i.e. critical system
catalogs) bugs could frequently lead to the corresponding relcache
entry being stale.
This set of bugs could cause actual data corruption as vacuum would
potentially not remove the correct row versions, potentially reviving
them at a later point. After 699bf7d05c some corruptions in this vein
were prevented, but the additional error checks could also trigger
spuriously. Examples of such errors are:
ERROR: found xmin ... from before relfrozenxid ...
and
ERROR: found multixact ... from before relminmxid ...
To be caused by this bug the errors have to occur on system catalog
tables.
The two bugs are:
1) Invalidations for nailed relations were ignored, based on the
theory that the relcache entry for such tables doesn't
change. Which is largely true, except for fields like relfrozenxid
etc. This means that changes to relations vacuumed in other
sessions weren't picked up by already existing sessions. Luckily
autovacuum doesn't have particularly longrunning sessions.
2) For shared *and* nailed relations, the shared relcache init file
was never invalidated while running. That means that for such
tables (e.g. pg_authid, pg_database) it's not just already existing
sessions that are affected, but even new connections are as well.
That explains why the reports usually were about pg_authid et. al.
To fix 1), revalidate the rd_rel portion of a relcache entry when
invalid. This implies a bit of extra complexity to deal with
bootstrapping, but it's not too bad. The fix for 2) is simpler,
simply always remove both the shared and local init files.
Alvaro Herrera [Wed, 6 Jun 2018 18:46:53 +0000 (14:46 -0400)]
Fix function code in error report
This bug causes a lseek() failure to be reported as a "could not open"
failure in the error message, muddling bug reports. I introduced this
copy-and-pasteo in commit 78e122010422.
Noticed while reviewing code for bug report #15221, from lily liang. In
version 10 the affected function is only used by multixact.c and
commit_ts, and only in corner-case circumstances, neither of which are
involved in the reported bug (a pg_subtrans failure.)
Tom Lane [Fri, 25 May 2018 18:31:07 +0000 (14:31 -0400)]
Fix misidentification of SQL statement type in plpgsql's exec_stmt_execsql.
To distinguish SQL statements that are INSERT/UPDATE/DELETE from other
ones, exec_stmt_execsql looked at the post-rewrite form of the statement
rather than the original. This is problematic because it did that only
during first execution of the statement (in a session), but the correct
answer could change later due to addition or removal of DO INSTEAD rules
during the session. That could lead to an Assert failure, as reported
by Tushar Ahuja and Robert Haas. In non-assert builds, there's a hazard
that we would fail to enforce STRICT behavior when we'd be expected to.
That would happen if an initially present DO INSTEAD, that replaced the
original statement with one of a different type, were removed; after that
the statement should act "normally", including strictness enforcement, but
it didn't. (The converse case of enforcing strictness when we shouldn't
doesn't seem to be a hazard, as addition of a DO INSTEAD that changes the
statement type would always lead to acting as though the statement returned
zero rows, so that the strictness error could not fire.)
To fix, inspect the original form of the statement not the post-rewrite
form, making it valid to assume the answer can't change intra-session.
This should lead to the same answer in every case except when there is a
DO INSTEAD that changes the statement type; we will now set mod_stmt=true
anyway, while we would not have done so before. That breaks the Assert
in the SPI_OK_REWRITTEN code path, which expected the latter behavior.
It might be all right to assert mod_stmt rather than !mod_stmt there,
but I'm not entirely convinced that that'd always hold, so just remove
the assertion altogether.
This has been broken for a long time, so back-patch to all supported
branches.
Magnus Hagander [Fri, 25 May 2018 11:59:50 +0000 (13:59 +0200)]
Remove incorrect statement about IPC configuration on OpenBSD
kern.ipc.shm_use_phys is not a sysctl on OpenBSD, and SEMMAP is not
a kernel configuration option. These were probably copy pasteos from
when the documentation had a single paragraph for *BSD.
Tom Lane [Thu, 24 May 2018 16:07:42 +0000 (12:07 -0400)]
Properly schema-qualify additional object types in getObjectDescription().
Collations, conversions, extended statistics objects (in >= v10),
and all four types of text search objects have schema-qualified names.
getObjectDescription() ignored that and would emit just the base name of
the object, potentially producing wrong or at least highly misleading
output. Fix it to add the schema name whenever the object is not "visible"
in the current search path, as is the rule for other schema-qualifiable
object types.
Although in common situations the output won't change, this seems to me
(tgl) to be a bug worthy of back-patching, hence do so.
Tom Lane [Wed, 23 May 2018 23:04:34 +0000 (19:04 -0400)]
Fix simple_prompt() to disable echo on Windows when stdin != terminal.
If echo = false, simple_prompt() is supposed to prevent echoing the
input (for password input). However, the Windows implementation applied
the mode change to STD_INPUT_HANDLE. That would not have the desired
effect if stdin isn't actually the terminal, for instance if the user
is piping something into psql. Fix it to apply the mode change to
the correct input file, so that passwords do not echo in such cases.
In passing, shorten and de-uglify this code by using #elif rather than
an #if nest and removing some duplicated code.
Back-patch to all supported versions. To simplify that, also back-patch
the portions of commit 9daec77e1 that got rid of an unnecessary
malloc/free in the same area.
Tom Lane [Tue, 22 May 2018 17:32:52 +0000 (13:32 -0400)]
Widen COPY FROM's current-line-number counter from 32 to 64 bits.
Because the code for the HEADER option skips a line when this counter
is zero, a very long COPY FROM WITH HEADER operation would drop a line
every 2^32 lines. A lesser but still unfortunate problem is that errors
would show a wrong input line number for errors occurring beyond the
2^31'st input line. While such large input streams seemed impractical
when this code was first written, they're not any more. Widening the
counter (and some associated variables) to uint64 should be enough to
prevent problems for the foreseeable future.
Andrew Gierth [Mon, 21 May 2018 16:02:17 +0000 (17:02 +0100)]
Fix SQL:2008 FETCH FIRST syntax to allow parameters.
OFFSET <x> ROWS FETCH FIRST <y> ROWS ONLY syntax is supposed to accept
<simple value specification>, which includes parameters as well as
literals. When this syntax was added all those years ago, it was done
inconsistently, with <x> and <y> being different subsets of the
standard syntax.
Rectify that by making <x> and <y> accept the same thing, and allowing
either a (signed) numeric literal or a c_expr there, which allows for
parameters, variables, and parenthesized arbitrary expressions.
Per bug #15200 from Lukas Eder.
Backpatch all the way, since this has been broken from the start.
Tom Lane [Sun, 20 May 2018 15:40:55 +0000 (11:40 -0400)]
printf("%lf") is not portable, so omit the "l".
The "l" (ell) width spec means something in the corresponding scanf usage,
but not here. While modern POSIX says that applying "l" to "f" and other
floating format specs is a no-op, SUSv2 says it's undefined. Buildfarm
experience says that some old compilers emit warnings about it, and at
least one old stdio implementation (mingw's "ANSI" option) actually
produces wrong answers and/or crashes.
Tom Lane [Sat, 19 May 2018 18:22:19 +0000 (14:22 -0400)]
Support platforms where strtoll/strtoull are spelled __strtoll/__strtoull.
Ancient HPUX, for one, does this. We hadn't noticed due to the lack
of regression tests that required a working strtoll.
(I was slightly tempted to remove the other historical spelling,
strto[u]q, since it seems we have no buildfarm members testing that case.
But I refrained.)
Tom Lane [Sat, 19 May 2018 02:42:10 +0000 (22:42 -0400)]
Arrange to supply declarations for strtoll/strtoull if needed.
Buildfarm member dromedary is still unhappy about the recently-added
ecpg "long long" tests. The reason turns out to be that it includes
"-ansi" in its CFLAGS, and in their infinite wisdom Apple have decided
to hide the declarations of strtoll/strtoull in C89-compliant builds.
(I find it pretty curious that they hide those function declarations
when you can nonetheless declare a "long long" variable, but anyway
that is their behavior, both on dromedary's obsolete macOS version and
the newest and shiniest.) As a result, gcc assumes these functions
return "int", leading naturally to wrong results.
(Looking at dromedary's past build results, it's evident that this
problem also breaks pg_strtouint64() on 32-bit platforms; but we
evidently have no regression tests that exercise that function with
values above 32 bits.)
To fix, supply declarations for these functions when the platform
provides the functions but not the declarations, using the same type
of mechanism as we use for some other similar cases.
Tom Lane [Fri, 18 May 2018 23:03:32 +0000 (19:03 -0400)]
Hot-fix ecpg regression test for missing ecpg_config.h inclusion.
I don't think this is really the best long-term answer, and in
particular it doesn't fix the pre-existing hazard in sqltypes.h.
But for the moment let's just try to make the buildfarm green again.
Tom Lane [Fri, 18 May 2018 17:04:59 +0000 (13:04 -0400)]
Add some test coverage for ecpg's "long long" support.
This will only actually exercise the "long long" code paths on platforms
where "long" is 32 bits --- otherwise, the SQL bigint type maps to
plain "long", and we will test that code path instead. But that's
probably sufficient coverage, and anyway we weren't testing either
code path before.
Tom Lane [Fri, 18 May 2018 16:52:28 +0000 (12:52 -0400)]
Recognize that MSVC can support strtoll() and strtoull().
This is needed for full support of "long long" variables in ecpg, but
the previous patch for bug #15080 (commits 51057feaa et al) missed it.
In MSVC versions where the functions don't exist under those names,
we can nonetheless use _strtoi64() and _strtoui64().
Tom Lane [Wed, 16 May 2018 17:46:09 +0000 (13:46 -0400)]
Fix misprocessing of equivalence classes involving record_eq().
canonicalize_ec_expression() is supposed to agree with coerce_type() as to
whether a RelabelType should be inserted to make a subexpression be valid
input for the operators of a given opclass. However, it did the wrong
thing with named-composite-type inputs to record_eq(): it put in a
RelabelType to RECORDOID, which the parser doesn't. In some cases this was
harmless because all code paths involving a particular equivalence class
did the same thing, but in other cases this would result in failing to
recognize a composite-type expression as being a member of an equivalence
class that it actually is a member of. The most obvious bad effect was to
fail to recognize that an index on a composite column could provide the
sort order needed for a mergejoin on that column, as reported by Teodor
Sigaev. I think there might be other, subtler, cases that result in
misoptimization. It also seems possible that an unwanted RelabelType
would sometimes get into an emitted plan --- but because record_eq and
friends don't examine the declared type of their input expressions, that
would not create any visible problems.
To fix, just treat RECORDOID as if it were a polymorphic type, which in
some sense it is. We might want to consider formalizing that a bit more
someday, but for the moment this seems to be the only place where an
IsPolymorphicType() test ought to include RECORDOID as well.
This has been broken for a long time, so back-patch to all supported
branches.
Tom Lane [Wed, 9 May 2018 17:55:27 +0000 (13:55 -0400)]
Update time zone data files to tzdata release 2018e.
DST law changes in North Korea. Redefinition of "daylight savings" in
Ireland, as well as for some past years in Namibia and Czechoslovakia.
Additional historical corrections for Czechoslovakia.
With this change, the IANA database models Irish timekeeping as following
"standard time" in summer, and "daylight savings" in winter, so that the
daylight savings offset is one hour behind standard time not one hour
ahead. This does not change their UTC offset (+1:00 in summer, 0:00 in
winter) nor their timezone abbreviations (IST in summer, GMT in winter),
though now "IST" is more correctly read as "Irish Standard Time" not "Irish
Summer Time". However, the "is_dst" column in the pg_timezone_names view
will now be true in winter and false in summer for the Europe/Dublin zone.
Similar changes were made for Namibia between 1994 and 2017, and for
Czechoslovakia between 1946 and 1947.
So far as I can find, no Postgres internal logic cares about which way
tm_isdst is reported; in particular, since commit b2cbced9e we do not
rely on it to decide how to interpret ambiguous timestamps during DST
transitions. So I don't think this change will affect any Postgres
behavior other than the timezone-view outputs.
Tom Lane [Mon, 7 May 2018 17:13:27 +0000 (13:13 -0400)]
Last-minute updates for release notes.
The set of functions that need parallel-safety adjustments isn't the
same in 9.6 as 10, so I shouldn't have blindly back-patched that list.
Adjust as needed. Also, provide examples of the commands to issue.
Peter Eisentraut [Tue, 13 Feb 2018 21:13:20 +0000 (16:13 -0500)]
Tweak tests to support Python 3.7
Python 3.7 removes the trailing comma in the repr() of
BaseException (see <https://bugs.python.org/issue30399>), leading to
test output differences. Work around that by composing the equivalent
test output in a more manual way.
Andrew Dunstan [Fri, 4 May 2018 19:22:48 +0000 (15:22 -0400)]
Provide for testing on python3 modules when under MSVC
This should have been done some years ago as promised in commit c4dcdd0c2. However, better late than never.
Along the way do a little housekeeping, including using a simpler test
for the python version being tested, and removing a redundant subroutine
parameter. These changes only apply back to release 9.5.
Tom Lane [Fri, 4 May 2018 16:26:25 +0000 (12:26 -0400)]
Sync our copy of the timezone library with IANA release tzcode2018e.
The non-cosmetic changes involve teaching the "zic" tzdata compiler about
negative DST. While I'm not currently intending that we start using
negative-DST data right away, it seems possible that somebody would try
to use our copy of zic with bleeding-edge IANA data. So we'd better be
out in front of this change code-wise, even though it doesn't matter for
the data file we're shipping.
Teodor Sigaev [Thu, 3 May 2018 17:10:34 +0000 (20:10 +0300)]
Add HOLD_INTERRUPTS section into FinishPreparedTransaction.
If an interrupt arrives in the middle of FinishPreparedTransaction
and any callback decide to call CHECK_FOR_INTERRUPTS (e.g.
RemoveTwoPhaseFile can write a warning with ereport, which checks for
interrupts) then it's possible to leave current GXact undeleted.
Tom Lane [Wed, 2 May 2018 21:32:41 +0000 (17:32 -0400)]
Revert back-branch changes in power()'s behavior for NaN inputs.
Per discussion, the value of fixing these bugs in the back branches
doesn't outweigh the downsides of changing corner-case behavior in
a minor release. Hence, revert commits 217d8f3a1 and 4d864de48 in
the v10 branch and the corresponding commits in 9.3-9.6.
Tom Lane [Mon, 30 Apr 2018 01:56:28 +0000 (21:56 -0400)]
Fix bogus list-iteration code in pg_regress.c, affecting ecpg tests only.
While looking at a recent buildfarm failure in the ecpg tests, I wondered
why the pg_regress output claimed the stderr part of the test failed, when
the regression diffs were clearly for the stdout part. Looking into it,
the reason is that pg_regress.c's logic for iterating over three parallel
lists is wrong, and has been wrong since it was written: it advances the
"tag" pointer at a different place in the loop than the other two pointers.
Fix that.
Tom Lane [Sun, 29 Apr 2018 22:15:16 +0000 (18:15 -0400)]
Avoid wrong results for power() with NaN input on more platforms.
Buildfarm results show that the modern POSIX rule that 1 ^ NaN = 1 is not
honored on *BSD until relatively recently, and really old platforms don't
believe that NaN ^ 0 = 1 either. (This is unsurprising, perhaps, since
SUSv2 doesn't require either behavior.) In hopes of getting to platform
independent behavior, let's deal with all the NaN-input cases explicitly
in dpow().
Note that numeric_power() doesn't know either of these special cases.
But since that behavior is platform-independent, I think it should be
addressed separately, and probably not back-patched.
Tom Lane [Sun, 29 Apr 2018 19:50:08 +0000 (15:50 -0400)]
Update time zone data files to tzdata release 2018d.
DST law changes in Palestine and Antarctica (Casey Station). Historical
corrections for Portugal and its colonies, as well as Enderbury, Jamaica,
Turks & Caicos Islands, and Uruguay.
Tom Lane [Sun, 29 Apr 2018 19:21:45 +0000 (15:21 -0400)]
Avoid wrong results for power() with NaN input on some platforms.
Per spec, the result of power() should be NaN if either input is NaN.
It appears that on some versions of Windows, the libc function does
return NaN, but it also sets errno = EDOM, confusing our code that
attempts to work around shortcomings of other platforms. Hence, add
guard tests to avoid substituting a wrong result for the right one.
It's been like this for a long time (and the odd behavior only appears
in older MSVC releases, too) so back-patch to all supported branches.
Tom Lane [Fri, 20 Apr 2018 19:19:17 +0000 (15:19 -0400)]
Change more places to be less trusting of RestrictInfo.is_pushed_down.
On further reflection, commit e5d83995e didn't go far enough: pretty much
everywhere in the planner that examines a clause's is_pushed_down flag
ought to be changed to use the more complicated behavior where we also
check the clause's required_relids. Otherwise we could make incorrect
decisions about whether, say, a clause is safe to use as a hash clause.
Some (many?) of these places are safe as-is, either because they are
never reached while considering a parameterized path, or because there
are additional checks that would reject a pushed-down clause anyway.
However, it seems smarter to just code them all the same way rather
than rely on easily-broken reasoning of that sort.
In support of that, invent a new macro RINFO_IS_PUSHED_DOWN that should
be used in place of direct tests on the is_pushed_down flag.
Like the previous patch, back-patch to all supported branches.
Tom Lane [Thu, 19 Apr 2018 19:49:12 +0000 (15:49 -0400)]
Fix incorrect handling of join clauses pushed into parameterized paths.
In some cases a clause attached to an outer join can be pushed down into
the outer join's RHS even though the clause is not degenerate --- this
can happen if we choose to make a parameterized path for the RHS. If
the clause ends up attached to a lower outer join, we'd misclassify it
as being a "join filter" not a plain "filter" condition at that node,
leading to wrong query results.
To fix, teach extract_actual_join_clauses to examine each join clause's
required_relids, not just its is_pushed_down flag. (The latter now
seems vestigial, or at least in need of rethinking, but we won't do
anything so invasive as redefining it in a bug-fix patch.)
This has been wrong since we introduced parameterized paths in 9.2,
though it's evidently hard to hit given the lack of previous reports.
The test case used here involves a lateral function call, and I think
that a lateral reference may be required to get the planner to select
a broken plan; though I wouldn't swear to that. In any case, even if
LATERAL is needed to trigger the bug, it still affects all supported
branches, so back-patch to all.
Per report from Andreas Karlsson. Thanks to Andrew Gierth for
preliminary investigation.
The buffer was 100 bytes long, which is barely sufficient when the
version string gets longer (such as by configure --with-extra-version).
Set it to MAXPGPATH.
Tom Lane [Mon, 16 Apr 2018 20:06:47 +0000 (16:06 -0400)]
Fix broken collation-aware searches in SP-GiST text opclass.
spg_text_leaf_consistent() supposed that it should compare only
Min(querylen, entrylen) bytes of the two strings, and then deal with
any excess bytes in one string or the other by assuming the longer
string is greater if the prefixes are equal. Quite aside from the
fact that that's just wrong in some locales (e.g., 'ch' is not less
than 'd' in cs_CZ), it also risked passing incomplete multibyte
characters to strcoll(), with ensuing bad results.
Instead, just pass the full strings to varstr_cmp, and let it decide
what to do about unequal-length strings.
Fortunately, this error doesn't imply any index corruption, it's just
that searches might return the wrong set of entries.
Per report from Emre Hasegeli, though this is not his patch.
Thanks to Peter Geoghegan for review and discussion.
This code was born broken, so back-patch to all supported branches.
In HEAD, I failed to resist the temptation to do a bit of cosmetic
cleanup/pgindent'ing on 710d90da1, too.
Tom Lane [Sun, 15 Apr 2018 17:02:12 +0000 (13:02 -0400)]
Fix potentially-unportable code in contrib/adminpack.
Spelling access(2)'s second argument as "2" is just horrid.
POSIX makes no promises as to the numeric values of W_OK and related
macros. Even if it accidentally works as intended on every supported
platform, it's still unreadable and inconsistent with adjacent code.
In passing, don't spell "NULL" as "0" either. Yes, that's legal C;
no, it's not project style.
Back-patch, just in case the unportability is real and not theoretical.
(Most likely, even if a platform had different bit assignments for
access()'s modes, there'd not be an observable behavior difference
here; but I'm being paranoid today.)
Tom Lane [Fri, 13 Apr 2018 16:53:46 +0000 (12:53 -0400)]
In libpq, free any partial query result before collecting a server error.
We'd throw away the partial result anyway after parsing the error message.
Throwing it away beforehand costs nothing and reduces the risk of
out-of-memory failure. Also, at least in systems that behave like
glibc/Linux, if the partial result was very large then the error PGresult
would get allocated at high heap addresses, preventing the heap storage
used by the partial result from being released to the OS until the error
PGresult is freed.
In psql >= 9.6, we hold onto the error PGresult until another error is
received (for \errverbose), so that this behavior causes a seeming
memory leak to persist for awhile, as in a recent complaint from
Darafei Praliaskouski. This is a potential performance regression from
older versions, justifying back-patching at least that far. But similar
behavior may occur in other client applications, so it seems worth just
back-patching to all supported branches.
Tom Lane [Thu, 12 Apr 2018 22:39:52 +0000 (18:39 -0400)]
Fix bogus affix-merging code.
NISortAffixes() compared successive compound affixes incorrectly,
thus possibly failing to merge identical affixes, or (less likely)
merging ones that shouldn't be merged. The user-visible effects
of this are unclear, to me anyway.
Per bug #15150 from Alexander Lakhin. It's been broken for a long time,
so back-patch to all supported branches.
Tom Lane [Wed, 11 Apr 2018 22:11:30 +0000 (18:11 -0400)]
Ignore nextOid when replaying an ONLINE checkpoint.
The nextOid value is from the start of the checkpoint and may well be stale
compared to values from more recent XLOG_NEXTOID records. Previously, we
adopted it anyway, allowing the OID counter to go backwards during a crash.
While this should be harmless, it contributed to the severity of the bug
fixed in commit 0408e1ed5, by allowing duplicate TOAST OIDs to be assigned
immediately following a crash. Without this error, that issue would only
have arisen when TOAST objects just younger than a multiple of 2^32 OIDs
were deleted and then not vacuumed in time to avoid a conflict.
Tom Lane [Wed, 11 Apr 2018 21:41:10 +0000 (17:41 -0400)]
Do not select new object OIDs that match recently-dead entries.
When selecting a new OID, we take care to avoid picking one that's already
in use in the target table, so as not to create duplicates after the OID
counter has wrapped around. However, up to now we used SnapshotDirty when
scanning for pre-existing entries. That ignores committed-dead rows, so
that we could select an OID matching a deleted-but-not-yet-vacuumed row.
While that mostly worked, it has two problems:
* If recently deleted, the dead row might still be visible to MVCC
snapshots, creating a risk for duplicate OIDs when examining the catalogs
within our own transaction. Such duplication couldn't be visible outside
the object-creating transaction, though, and we've heard few if any field
reports corresponding to such a symptom.
* When selecting a TOAST OID, deleted toast rows definitely *are* visible
to SnapshotToast, and will remain so until vacuumed away. This leads to
a conflict that will manifest in errors like "unexpected chunk number 0
(expected 1) for toast value nnnnn". We've been seeing reports of such
errors from the field for years, but the cause was unclear before.
The fix is simple: just use SnapshotAny to search for conflicting rows.
This results in a slightly longer window before object OIDs can be
recycled, but that seems unlikely to create any large problems.
Make local copy of client hostnames in backend status array.
The other strings, application_name and query string, were snapshotted to
local memory in pgstat_read_current_status(), but we forgot to do that for
client hostnames. As a result, the client hostname would appear to change in
the local copy, if the client disconnected.
Backpatch to all supported versions.
Author: Edmund Horner Reviewed-by: Michael Paquier
Discussion: https://www.postgresql.org/message-id/CAMyN-kA7aOJzBmrYFdXcc7Z0NmW%2B5jBaf_m%3D_-77uRNyKC9r%3DA%40mail.gmail.com
Tom Lane [Sun, 8 Apr 2018 20:35:43 +0000 (16:35 -0400)]
Doc: clarify explanation of pg_dump usage.
This section confusingly used both "infile" and "outfile" to refer
to the same file, i.e. the textual output of pg_dump. Use "dumpfile"
for both cases, per suggestion from Jonathan Katz.
Tom Lane [Fri, 30 Mar 2018 22:14:51 +0000 (18:14 -0400)]
Fix bogus provolatile/proparallel markings on a few built-in functions.
Richard Yen reported that pg_upgrade failed if the target cluster had
force_parallel_mode = on, because binary_upgrade_create_empty_extension()
is marked parallel restricted, allowing it to be executed in parallel
mode, which complains because it tries to acquire an XID.
In general, no function that might try to modify database data should
be considered parallel safe or restricted, since execution of it might
force XID acquisition. We found several other examples of this mistake.
Furthermore, functions that execute user-supplied SQL queries or query
fragments, or pull data from user-supplied cursors, had better be marked
both volatile and parallel unsafe, because we don't know what the supplied
query or cursor might try to do. There were several tsquery and XML
functions that had the wrong proparallel marking for this, and some of
them were even mislabeled as to volatility.
All these bugs are old, dating back to 9.6 for the proparallel mistakes
and much further for the provolatile mistakes. We can't force a
catversion bump in the back branches, but we can at least ensure that
installations initdb'd in future have the right values.
Tom Lane [Sun, 25 Mar 2018 20:15:16 +0000 (16:15 -0400)]
Doc: add example of type resolution in nested UNIONs.
Section 10.5 didn't say explicitly that multiple UNIONs are resolved
pairwise. Since the resolution algorithm is described as taking any
number of inputs, readers might well think that a query like
"select x union select y union select z" would be resolved by
considering x, y, and z in one resolution step. But that's not what
happens (and I think that behavior is per SQL spec). Add an example
clarifying this point.
Noah Misch [Sat, 24 Mar 2018 03:31:03 +0000 (20:31 -0700)]
Don't qualify type pg_catalog.text in extend-extensions-example.
Extension scripts begin execution with pg_catalog at the front of the
search path, so type names reliably refer to pg_catalog. Remove these
superfluous qualifications. Earlier <programlisting> of this <sect1>
already omitted them. Back-patch to 9.3 (all supported versions).
Tom Lane [Fri, 23 Mar 2018 17:45:38 +0000 (13:45 -0400)]
Fix make rules that generate multiple output files.
For years, our makefiles have correctly observed that "there is no correct
way to write a rule that generates two files". However, what we did is to
provide empty rules that "generate" the secondary output files from the
primary one, and that's not right either. Depending on the details of
the creating process, the primary file might end up timestamped later than
one or more secondary files, causing subsequent make runs to consider the
secondary file(s) out of date. That's harmless in a plain build, since
make will just re-execute the empty rule and nothing happens. But it's
fatal in a VPATH build, since make will expect the secondary file to be
rebuilt in the build directory. This would manifest as "file not found"
failures during VPATH builds from tarballs, if we were ever unlucky enough
to ship a tarball with apparently out-of-date secondary files. (It's not
clear whether that has ever actually happened, but it definitely could.)
To ensure that secondary output files have timestamps >= their primary's,
change our makefile convention to be that we provide a "touch $@" action
not an empty rule. Also, make sure that this rule actually gets invoked
during a distprep run, else the hazard remains.
It's been like this a long time, so back-patch to all supported branches.
In HEAD, I skipped the changes in src/backend/catalog/Makefile, because
those rules are due to get replaced soon in the bootstrap data format
patch, and there seems no need to create a merge issue for that patch.
If for some reason we fail to land that patch in v11, we'll need to
back-fill the changes in that one makefile from v10.
Tom Lane [Thu, 22 Mar 2018 17:23:48 +0000 (13:23 -0400)]
Fix tuple counting in SP-GiST index build.
Count the number of tuples in the index honestly, instead of assuming
that it's the same as the number of tuples in the heap. (It might be
different if the index is partial.)
Tom Lane [Thu, 22 Mar 2018 00:03:29 +0000 (20:03 -0400)]
Fix mishandling of quoted-list GUC values in pg_dump and ruleutils.c.
Code that prints out the contents of setconfig or proconfig arrays in
SQL format needs to handle GUC_LIST_QUOTE variables differently from
other ones, because for those variables, flatten_set_variable_args()
already applied a layer of quoting. The value can therefore safely
be printed as-is, and indeed must be, or flatten_set_variable_args()
will muck it up completely on reload. For all other GUC variables,
it's necessary and sufficient to quote the value as a SQL literal.
We'd recognized the need for this long ago, but mis-analyzed the
need slightly, thinking that all GUC_LIST_INPUT variables needed
the special treatment. That's actually wrong, since a valid value
of a LIST variable might include characters that need quoting,
although no existing variables accept such values.
More to the point, we hadn't made any particular effort to keep the
various places that deal with this up-to-date with the set of variables
that actually need special treatment, meaning that we'd do the wrong
thing with, for example, temp_tablespaces values. This affects dumping
of SET clauses attached to functions, as well as ALTER DATABASE/ROLE SET
commands.
In ruleutils.c we can fix it reasonably honestly by exporting a guc.c
function that allows discovering the flags for a given GUC variable.
But pg_dump doesn't have easy access to that, so continue the old method
of having a hard-wired list of affected variable names. At least we can
fix it to have just one list not two, and update the list to match
current reality.
A remaining problem with this is that it only works for built-in
GUC variables. pg_dump's list obvious knows nothing of third-party
extensions, and even the "ask guc.c" method isn't bulletproof since
the relevant extension might not be loaded. There's no obvious
solution to that, so for now, we'll just have to discourage extension
authors from inventing custom GUCs that need GUC_LIST_QUOTE.
This has been busted for a long time, so back-patch to all supported
branches.
Michael Paquier and Tom Lane, reviewed by Kyotaro Horiguchi and
Pavel Stehule
Tom Lane [Sun, 18 Mar 2018 19:10:28 +0000 (15:10 -0400)]
Doc: note that statement-level view triggers require an INSTEAD OF trigger.
If a view lacks an INSTEAD OF trigger, DML on it can only work by rewriting
the command into a command on the underlying base table(s). Then we will
fire triggers attached to those table(s), not those for the view. This
seems appropriate from a consistency standpoint, but nowhere was the
behavior explicitly documented, so let's do that.
There was some discussion of throwing an error or warning if a statement
trigger is created on a view without creating a row INSTEAD OF trigger.
But a simple implementation of that would result in dump/restore ordering
hazards. Given that it's been like this all along, and we hadn't heard
a complaint till now, a documentation improvement seems sufficient.
Per bug #15106 from Pu Qun. Back-patch to all supported branches.
Tom Lane [Sat, 17 Mar 2018 19:38:15 +0000 (15:38 -0400)]
Fix overflow handling in plpgsql's integer FOR loops.
The test to exit the loop if the integer control value would overflow
an int32 turns out not to work on some ICC versions, as it's dependent
on the assumption that the compiler will execute the code as written
rather than "optimize" it. ICC lacks any equivalent of gcc's -fwrapv
switch, so it was optimizing on the assumption of no integer overflow,
and that breaks this. Rewrite into a form that in fact does not
do any overflowing computations.
Per Tomas Vondra and buildfarm member fulmar. It's been like this
for a long time, although it was not till we added a regression test
case covering the behavior (in commit dd2243f2a) that the problem
became apparent. Back-patch to all supported versions.
Tom Lane [Sat, 17 Mar 2018 18:59:31 +0000 (14:59 -0400)]
Fix WHERE CURRENT OF when the referenced cursor uses an index-only scan.
"UPDATE/DELETE WHERE CURRENT OF cursor_name" failed, with an error message
like "cannot extract system attribute from virtual tuple", if the cursor
was using a index-only scan for the target table. Fix it by digging the
current TID out of the indexscan state.
It seems likely that the same failure could occur for CustomScan plans
and perhaps some FDW plan types, so that leaving this to be treated as an
internal error with an obscure message isn't as good an idea as it first
seemed. Hence, add a bit of heaptuple.c infrastructure to let us deliver
a more on-topic message. I chose to make the message match what you get
for the case where execCurrentOf can't identify the target scan node at
all, "cursor "foo" is not a simply updatable scan of table "bar"".
Perhaps it should be different, but we can always adjust that later.
In the future, it might be nice to provide hooks that would let custom
scan providers and/or FDWs deal with this in other ways; but that's
not a suitable topic for a back-patchable bug fix.
It's been like this all along, so back-patch to all supported branches.
Tom Lane [Fri, 16 Mar 2018 20:03:45 +0000 (16:03 -0400)]
Fix query-lifespan memory leakage in repeatedly executed hash joins.
ExecHashTableCreate allocated some memory that wasn't freed by
ExecHashTableDestroy, specifically the per-hash-key function information.
That's not a huge amount of data, but if one runs a query that repeats
a hash join enough times, it builds up. Fix by arranging for the data
in question to be kept in the hashtable's hashCxt instead of leaving it
"loose" in the query-lifespan executor context. (This ensures that we'll
also clean up anything that the hash functions allocate in fn_mcxt.)
Per report from Amit Khandekar. It's been like this forever, so back-patch
to all supported branches.
Tom Lane [Fri, 16 Mar 2018 17:44:34 +0000 (13:44 -0400)]
Doc: explicitly point out that enum values can't be dropped.
This was not stated in so many words anywhere. Document it to make
clear that it's a design limitation and not just an oversight or
documentation omission.
Tom Lane [Tue, 13 Mar 2018 17:24:27 +0000 (13:24 -0400)]
When updating reltuples after ANALYZE, just extrapolate from our sample.
The existing logic for updating pg_class.reltuples trusted the sampling
results only for the pages ANALYZE actually visited, preferring to
believe the previous tuple density estimate for all the unvisited pages.
While there's some rationale for doing that for VACUUM (first that
VACUUM is likely to visit a very nonrandom subset of pages, and second
that we know for sure that the unvisited pages did not change), there's
no such rationale for ANALYZE: by assumption, it's looked at an unbiased
random sample of the table's pages. Furthermore, in a very large table
ANALYZE will have examined only a tiny fraction of the table's pages,
meaning it cannot slew the overall density estimate very far at all.
In a table that is physically growing, this causes reltuples to increase
nearly proportionally to the change in relpages, regardless of what is
actually happening in the table. This has been observed to cause reltuples
to become so much larger than reality that it effectively shuts off
autovacuum, whose threshold for doing anything is a fraction of reltuples.
(Getting to the point where that would happen seems to require some
additional, not well understood, conditions. But it's undeniable that if
reltuples is seriously off in a large table, ANALYZE alone will not fix it
in any reasonable number of iterations, especially not if the table is
continuing to grow.)
Hence, restrict the use of vac_estimate_reltuples() to VACUUM alone,
and in ANALYZE, just extrapolate from the sample pages on the assumption
that they provide an accurate model of the whole table. If, by very bad
luck, they don't, at least another ANALYZE will fix it; in the old logic
a single bad estimate could cause problems indefinitely.
In HEAD, let's remove vac_estimate_reltuples' is_analyze argument
altogether; it was never used for anything and now it's totally pointless.
But keep it in the back branches, in case any third-party code is calling
this function.
Per bug #15005. Back-patch to all supported branches.
David Gould, reviewed by Alexander Kuzmenkov, cosmetic changes by me
Tom Lane [Tue, 13 Mar 2018 16:28:16 +0000 (12:28 -0400)]
Avoid holding AutovacuumScheduleLock while rechecking table statistics.
In databases with many tables, re-fetching the statistics takes some time,
so that this behavior seriously decreases the available concurrency for
multiple autovac workers. There's discussion afoot about more complete
fixes, but a simple and back-patchable amelioration is to claim the table
and release the lock before rechecking stats. If we find out there's no
longer a reason to process the table, re-taking the lock to un-claim the
table is cheap enough.
(This patch is quite old, but got lost amongst a discussion of more
aggressive fixes. It's not clear when or if such a fix will be
accepted, but in any case it'd be unlikely to get back-patched.
Let's do this now so we have some improvement for the back branches.)
In passing, make the normal un-claim step take AutovacuumScheduleLock
not AutovacuumLock, since that is what is documented to protect the
wi_tableoid field. This wasn't an actual bug in view of the fact that
readers of that field hold both locks, but it creates some concurrency
penalty against operations that need only AutovacuumLock.
Tom Lane [Sun, 11 Mar 2018 22:10:43 +0000 (18:10 -0400)]
Fix improper uses of canonicalize_qual().
One of the things canonicalize_qual() does is to remove constant-NULL
subexpressions of top-level AND/OR clauses. It does that on the assumption
that what it's given is a top-level WHERE clause, so that NULL can be
treated like FALSE. Although this is documented down inside a subroutine
of canonicalize_qual(), it wasn't mentioned in the documentation of that
function itself, and some callers hadn't gotten that memo.
Notably, commit d007a9505 caused get_relation_constraints() to apply
canonicalize_qual() to CHECK constraints. That allowed constraint
exclusion to misoptimize situations in which a CHECK constraint had a
provably-NULL subclause, as seen in the regression test case added here,
in which a child table that should be scanned is not. (Although this
thinko is ancient, the test case doesn't fail before 9.2, for reasons
I've not bothered to track down in detail. There may be related cases
that do fail before that.)
More recently, commit f0e44751d added an independent bug by applying
canonicalize_qual() to index expressions, which is even sillier since
those might not even be boolean. If they are, though, I think this
could lead to making incorrect index entries for affected index
expressions in v10. I haven't attempted to prove that though.
To fix, add an "is_check" parameter to canonicalize_qual() to specify
whether it should assume WHERE or CHECK semantics, and make it perform
NULL-elimination accordingly. Adjust the callers to apply the right
semantics, or remove the call entirely in cases where it's not known
that the expression has one or the other semantics. I also removed
the call in some cases involving partition expressions, where it should
be a no-op because such expressions should be canonical already ...
and was a no-op, independently of whether it could in principle have
done something, because it was being handed the qual in implicit-AND
format which isn't what it expects. In HEAD, add an Assert to catch
that type of mistake in future.
This represents an API break for external callers of canonicalize_qual().
While that's intentional in HEAD to make such callers think about which
case applies to them, it seems like something we probably wouldn't be
thanked for in released branches. Hence, in released branches, the
extra parameter is added to a new function canonicalize_qual_ext(),
and canonicalize_qual() is a wrapper that retains its old behavior.
Patch by me with suggestions from Dean Rasheed. Back-patch to all
supported branches.
Tom Lane [Sun, 4 Mar 2018 01:31:35 +0000 (20:31 -0500)]
Fix assorted issues in convert_to_scalar().
If convert_to_scalar is passed a pair of datatypes it can't cope with,
its former behavior was just to elog(ERROR). While this is OK so far as
the core code is concerned, there's extension code that would like to use
scalarltsel/scalargtsel/etc as selectivity estimators for operators that
work on non-core datatypes, and this behavior is a show-stopper for that
use-case. If we simply allow convert_to_scalar to return FALSE instead of
outright failing, then the main logic of scalarltsel/scalargtsel will work
fine for any operator that behaves like a scalar inequality comparison.
The lack of conversion capability will mean that we can't estimate to
better than histogram-bin-width precision, since the code will effectively
assume that the comparison constant falls at the middle of its bin. But
that's still a lot better than nothing. (Someday we should provide a way
for extension code to supply a custom version of convert_to_scalar, but
today is not that day.)
While poking at this issue, we noted that the existing code for handling
type bytea in convert_to_scalar is several bricks shy of a load.
It assumes without checking that if the comparison value is type bytea,
the bounds values are too; in the worst case this could lead to a crash.
It also fails to detoast the input values, so that the comparison result is
complete garbage if any input is toasted out-of-line, compressed, or even
just short-header. I'm not sure how often such cases actually occur ---
the bounds values, at least, are probably safe since they are elements of
an array and hence can't be toasted. But that doesn't make this code OK.
Back-patch to all supported branches, partly because author requested that,
but mostly because of the bytea bugs. The change in API for the exposed
routine convert_network_to_scalar() is theoretically a back-patch hazard,
but it seems pretty unlikely that any third-party code is calling that
function directly.
Tom Lane [Fri, 2 Mar 2018 16:22:42 +0000 (11:22 -0500)]
Make gistvacuumcleanup() count the actual number of index tuples.
Previously, it just returned the heap tuple count, which might be only an
estimate, and would be completely the wrong thing if the index is partial.
Since this function scans every index page anyway to find free pages,
it's practically free to count the surviving index tuples. Let's do that
and return an accurate count.
This is easily visible as a wrong reltuples value for a partial GiST
index following VACUUM, so back-patch to all supported branches.
Tom Lane [Thu, 1 Mar 2018 21:23:30 +0000 (16:23 -0500)]
Use ereport not elog for some corrupt-HOT-chain reports.
These errors have been seen in the field in corrupted-data situations.
It seems worthwhile to report them with ERRCODE_DATA_CORRUPTED, rather
than the generic ERRCODE_INTERNAL_ERROR, for the benefit of log monitoring
and tools like amcheck. However, use errmsg_internal so that the text
strings still aren't translated; it seems unlikely to be worth
translators' time to do so.
Back-patch to 9.3, like the predecessor commit d70cf811f that introduced
these elog calls originally (replacing Asserts).
Alvaro Herrera [Thu, 1 Mar 2018 21:07:46 +0000 (18:07 -0300)]
Relax overly strict sanity check for upgraded ancient databases
Commit 4800f16a7ad0 added some sanity checks to ensure we don't
accidentally corrupt data, but in one of them we failed to consider the
effects of a database upgraded from 9.2 or earlier, where a tuple
exclusively locked prior to the upgrade has a slightly different bit
pattern. Fix that by using the macro that we fixed in commit 74ebba84aeb6 for similar situations.
Reported-by: Alexandre Garcia Reviewed-by: Andres Freund
Discussion: https://postgr.es/m/CAPYLKR6yxV4=pfW0Gwij7aPNiiPx+3ib4USVYnbuQdUtmkMaEA@mail.gmail.com
Andres suspects that this bug may have wider ranging consequences, but I
couldn't find anything.
Tom Lane [Thu, 1 Mar 2018 18:27:44 +0000 (13:27 -0500)]
Fix build failure on MSVC.
Commit 824cceded introduced use of pg_malloc and pg_realloc into
specscanner.l, but it isn't working in 9.3 on MSVC. Evidently we
added the infrastructure for that in 9.4. Since the chance of an
actual OOM here is tiny, and the consequences would only be an
isolation test failure, and we have unchecked OOM hazards elsewhere
in this file in 9.3, it's not worth sweating over. Just replace
the calls with malloc and realloc.
projects / postgresql / log