Robert Haas [Wed, 6 Dec 2017 13:49:30 +0000 (08:49 -0500)]
Report failure to start a background worker.
When a worker is flagged as BGW_NEVER_RESTART and we fail to start it,
or if it is not marked BGW_NEVER_RESTART but is terminated before
startup succeeds, what BgwHandleStatus should be reported? The
previous code really hadn't considered this possibility (as indicated
by the comments which ignore it completely) and would typically return
BGWH_NOT_YET_STARTED, but that's not a good answer, because then
there's no way for code using GetBackgroundWorkerPid() to tell the
difference between a worker that has not started but will start
later and a worker that has not started and will never be started.
So, when this case happens, return BGWH_STOPPED instead. Update the
comments to reflect this.
The preceding fix by itself is insufficient to fix the problem,
because the old code also didn't send a notification to the process
identified in bgw_notify_pid when startup failed. That might've
been technically correct under the theory that the status of the
worker was BGWH_NOT_YET_STARTED, because the status would indeed not
change when the worker failed to start, but now that we're more
usefully reporting BGWH_STOPPED, a notification is needed.
Without these fixes, code which starts background workers and then
uses the recommended APIs to wait for those background workers to
start would hang indefinitely if the postmaster failed to fork a
worker.
Tom Lane [Mon, 4 Dec 2017 22:02:52 +0000 (17:02 -0500)]
Clean up assorted messiness around AllocateDir() usage.
This patch fixes a couple of low-probability bugs that could lead to
reporting an irrelevant errno value (and hence possibly a wrong SQLSTATE)
concerning directory-open or file-open failures. It also fixes places
where we took shortcuts in reporting such errors, either by using elog
instead of ereport or by using ereport but forgetting to specify an
errcode. And it eliminates a lot of just plain redundant error-handling
code.
In service of all this, export fd.c's formerly-static function
ReadDirExtended, so that external callers can make use of the coding
pattern
dir = AllocateDir(path);
while ((de = ReadDirExtended(dir, path, LOG)) != NULL)
if they'd like to treat directory-open failures as mere LOG conditions
rather than errors. Also fix FreeDir to be a no-op if we reach it
with dir == NULL, as such a coding pattern would cause.
Then, remove code at many call sites that was throwing an error or log
message for AllocateDir failure, as ReadDir or ReadDirExtended can handle
that job just fine. Aside from being a net code savings, this gets rid of
a lot of not-quite-up-to-snuff reports, as mentioned above. (In some
places these changes result in replacing a custom error message such as
"could not open tablespace directory" with more generic wording "could not
open directory", but it was agreed that the custom wording buys little as
long as we report the directory name.) In some other call sites where we
can't just remove code, change the error reports to be fully
project-style-compliant.
Also reorder code in restoreTwoPhaseData that was acquiring a lock
between AllocateDir and ReadDir; in the unlikely but surely not
impossible case that LWLockAcquire changes errno, AllocateDir failures
would be misreported. There is no great value in opening the directory
before acquiring TwoPhaseStateLock, so just do it in the other order.
Also fix CheckXLogRemoved to guarantee that it preserves errno,
as quite a number of call sites are implicitly assuming. (Again,
it's unlikely but I think not impossible that errno could change
during a SpinLockAcquire. If so, this function was broken for its
own purposes as well as breaking callers.)
And change a few places that were using not-per-project-style messages,
such as "could not read directory" when "could not open directory" is
more correct.
Back-patch the exporting of ReadDirExtended, in case we have occasion
to back-patch some fix that makes use of it; it's not needed right now
but surely making it global is pretty harmless. Also back-patch the
restoreTwoPhaseData and CheckXLogRemoved fixes. The rest of this is
essentially cosmetic and need not get back-patched.
Michael Paquier, with a bit of additional work by me
Noah Misch [Thu, 30 Nov 2017 08:57:22 +0000 (00:57 -0800)]
Fix non-GNU makefiles for AIX make.
Invoking the Makefile without an explicit target was building every
possible target instead of just the "all" target. Back-patch to 9.3
(all supported versions).
Tom Lane [Mon, 27 Nov 2017 22:53:56 +0000 (17:53 -0500)]
Fix creation of resjunk tlist entries for inherited mixed UPDATE/DELETE.
rewriteTargetListUD's processing is dependent on the relkind of the query's
target table. That was fine at the time it was made to act that way, even
for queries on inheritance trees, because all tables in an inheritance tree
would necessarily be plain tables. However, the 9.5 feature addition
allowing some members of an inheritance tree to be foreign tables broke the
assumption that rewriteTargetListUD's output tlist could be applied to all
child tables with nothing more than column-number mapping. This led to
visible failures if foreign child tables had row-level triggers, and would
also break in cases where child tables belonged to FDWs that used methods
other than CTID for row identification.
To fix, delay running rewriteTargetListUD until after the planner has
expanded inheritance, so that it is applied separately to the (already
mapped) tlist for each child table. We can conveniently call it from
preprocess_targetlist. Refactor associated code slightly to avoid the
need to heap_open the target relation multiple times during
preprocess_targetlist. (The APIs remain a bit ugly, particularly around
the point of which steps scribble on parse->targetList and which don't.
But avoiding such scribbling would require a change in FDW callback APIs,
which is more pain than it's worth.)
Also fix ExecModifyTable to ensure that "tupleid" is reset to NULL when
we transition from rows providing a CTID to rows that don't. (That's
really an independent bug, but it manifests in much the same cases.)
Add a regression test checking one manifestation of this problem, which
was that row-level triggers on a foreign child table did not work right.
Back-patch to 9.5 where the problem was introduced.
Etsuro Fujita, reviewed by Ildus Kurbangaliev and Ashutosh Bapat
Tom Lane [Sun, 26 Nov 2017 20:17:25 +0000 (15:17 -0500)]
Pad XLogReaderState's main_data buffer more aggressively.
Originally, we palloc'd this buffer just barely big enough to hold the
largest xlog record seen so far. It turns out that that can result in
valgrind complaints, because some compilers will emit code that assumes
it can safely fetch padding bytes at the end of a struct, and those
padding bytes were unallocated so far as aset.c was concerned. We can
fix that by MAXALIGN'ing the palloc request size, ensuring that it is big
enough to include any possible padding that might've been omitted from
the on-disk record.
An additional objection to the original coding is that it could result in
many repeated palloc cycles, in the worst case where we see a series of
gradually larger xlog records. We can ameliorate that cheaply by
imposing a minimum buffer size that's large enough for most xlog records.
BLCKSZ/2 was chosen after a bit of discussion.
In passing, remove an obsolete comment in struct xl_heap_new_cid that the
combocid field is free due to alignment considerations. Perhaps that was
true at some point, but it's not now.
Joe Conway [Sun, 26 Nov 2017 17:50:15 +0000 (09:50 -0800)]
Make has_sequence_privilege support WITH GRANT OPTION
The various has_*_privilege() functions all support an optional
WITH GRANT OPTION added to the supported privilege types to test
whether the privilege is held with grant option. That is, all except
has_sequence_privilege() variations. Fix that.
Tom Lane [Sat, 25 Nov 2017 20:30:11 +0000 (15:30 -0500)]
Replace raw timezone source data with IANA's new compact format.
Traditionally IANA has distributed their timezone data in pure source
form, replete with extensive historical comments. As of release 2017c,
they've added a compact single-file format that omits comments and
abbreviates command keywords. This form is way shorter than the pure
source, even before considering its allegedly better compressibility.
Hence, let's distribute the data in that form rather than pure source.
I'm pushing this now, rather than at the next timezone database update,
so that it's easy to confirm that this data file produces compiled zic
output that's identical to what we were getting before.
Tom Lane [Sat, 25 Nov 2017 19:42:10 +0000 (14:42 -0500)]
Avoid formally-undefined use of memcpy() in hstoreUniquePairs().
hstoreUniquePairs() often called memcpy with equal source and destination
pointers. Although this is almost surely harmless in practice, it's
undefined according to the letter of the C standard. Some versions of
valgrind will complain about it, and some versions of libc as well
(cf. commit ad520ec4a). Tweak the code to avoid doing that.
Noted by Tomas Vondra. Back-patch to all supported versions because
of the hazard of libc assertions.
Tom Lane [Sat, 25 Nov 2017 19:15:48 +0000 (14:15 -0500)]
Repair failure with SubPlans in multi-row VALUES lists.
When nodeValuesscan.c was written, it was impossible to have a SubPlan in
VALUES --- any sub-SELECT there would have to be uncorrelated and thereby
would produce an InitPlan instead. We therefore took a shortcut in the
logic that throws away a ValuesScan's per-row expression evaluation data
structures. This was broken by the introduction of LATERAL however; a
sub-SELECT containing a lateral reference produces a correlated SubPlan.
The cleanest fix for this would be to give up the optimization of
discarding the expression eval state. But that still seems pretty
unappetizing for long VALUES lists. It seems to work to just prevent
the subexpressions from hooking into the ValuesScan node's subPlan
list, so let's do that and see how well it works. (If this breaks,
due to additional connections between the subexpressions and the outer
query structures, we might consider compromises like throwing away data
only for VALUES rows not containing SubPlans.)
Per bug #14924 from Christian Duta. Back-patch to 9.3 where LATERAL
was introduced.
Dean Rasheed [Fri, 24 Nov 2017 12:00:00 +0000 (12:00 +0000)]
Doc: add a summary table to the CREATE POLICY docs.
This table summarizes which RLS policy expressions apply to each
command type, and whether they apply to the old or new tuples (or
both), which saves reading through a lot of text.
Rod Taylor, hacked on by me. Reviewed by Fabien Coelho.
Tom Lane [Fri, 24 Nov 2017 05:29:20 +0000 (00:29 -0500)]
Fix unstable regression test added by commits 59b71c6fe et al.
The query didn't really have a preferred index, leading to platform-
specific choices of which one to use. Adjust it to make sure tenk1_hundred
is always chosen.
Noah Misch [Fri, 24 Nov 2017 04:22:04 +0000 (20:22 -0800)]
Support linking with MinGW-built Perl.
This is necessary for ActivePerl 5.18 onwards and for Strawberry Perl.
It is not sufficient for 32-bit builds with newer Visual Studio; these
fail with error LINK2026. Back-patch to 9.3 (all supported versions).
Andres Freund [Fri, 24 Nov 2017 01:14:43 +0000 (17:14 -0800)]
Fix handling of NULLs returned by aggregate combine functions.
When strict aggregate combine functions, used in multi-stage/parallel
aggregation, returned NULL, we didn't check for that, invoking the
combine function with NULL the next round, despite it being strict.
The equivalent code invoking normal transition functions has a check
for that situation, which did not get copied in a7de3dc5c346. Fix the
bug by adding the equivalent check.
Based on a quick look I could not find any strict combine functions in
core actually returning NULL, and it doesn't seem very likely external
users have done so. So this isn't likely to have caused issues in
practice.
Reported-By: Andres Freund
Author: Andres Freund
Discussion: https://postgr.es/m/20171121033642.7xvmjqrl4jdaaat3@alap3.anarazel.de
Backpatch: 9.6, where parallel aggregation was introduced
Robert Haas [Tue, 21 Nov 2017 18:56:24 +0000 (13:56 -0500)]
Provide for forward compatibility with future minor protocol versions.
Previously, any attempt to request a 3.x protocol version other than
3.0 would lead to a hard connection failure, which made the minor
protocol version really no different from the major protocol version
and precluded gentle protocol version breaks. Instead, when the
client requests a 3.x protocol version where x is greater than 0, send
the new NegotiateProtocolVersion message to convey that we support
only 3.0. This makes it possible to introduce new minor protocol
versions without requiring a connection retry when the server is
older.
In addition, if the startup packet includes name/value pairs where
the name starts with "_pq_.", assume that those are protocol options,
not GUCs. Include those we don't support (i.e. all of them, at
present) in the NegotiateProtocolVersion message so that the client
knows they were not understood. This makes it possible for the
client to request previously-unsupported features without bumping
the protocol version at all; the client can tell from the server's
response whether the option was understood.
It will take some time before servers that support these new
facilities become common in the wild; to speed things up and make
things easier for a future 3.1 protocol version, back-patch to all
supported releases.
Tom Lane [Mon, 20 Nov 2017 22:57:46 +0000 (17:57 -0500)]
Add support for Motorola 88K to s_lock.h.
Apparently there are still people out there who care about this old
architecture. They probably care about dusty versions of Postgres
too, so back-patch to all supported branches.
David Carlier (from a patch being carried by OpenBSD packagers)
Tom Lane [Sat, 18 Nov 2017 21:46:30 +0000 (16:46 -0500)]
Fix compiler warning in rangetypes_spgist.c.
On gcc 7.2.0, comparing pointer to (Datum) 0 produces a warning.
Treat it as a simple pointer to avoid that; this is more consistent
with comparable code elsewhere, anyway.
Tom Lane [Fri, 17 Nov 2017 17:46:52 +0000 (12:46 -0500)]
Provide modern examples of how to auto-start Postgres on macOS.
The scripts in contrib/start-scripts/osx don't work at all on macOS
10.10 (Yosemite) or later, because they depend on SystemStarter which
Apple deprecated long ago and removed in 10.10. Add a new subdirectory
contrib/start-scripts/macos with scripts that use the newer launchd
infrastructure.
Since this problem is independent of which Postgres version you're using,
back-patch to all supported branches.
Robert Haas [Thu, 16 Nov 2017 19:19:27 +0000 (14:19 -0500)]
Fix broken cleanup interlock for GIN pending list.
The pending list must (for correctness) always be cleaned up by vacuum, and
should (for the avoidance of surprising behavior) always be cleaned up
by an explicit call to gin_clean_pending_list, but cleanup is optional
when inserting. The old logic got this backward: cleanup was forced
if (stats == NULL), but that's going to be *false* when vacuuming and
*true* for inserts.
Tom Lane [Tue, 14 Nov 2017 22:49:49 +0000 (17:49 -0500)]
Prevent int128 from requiring more than MAXALIGN alignment.
Our initial work with int128 neglected alignment considerations, an
oversight that came back to bite us in bug #14897 from Vincent Lachenal.
It is unsurprising that int128 might have a 16-byte alignment requirement;
what's slightly more surprising is that even notoriously lax Intel chips
sometimes enforce that.
Raising MAXALIGN seems out of the question: the costs in wasted disk and
memory space would be significant, and there would also be an on-disk
compatibility break. Nor does it seem very practical to try to allow some
data structures to have more-than-MAXALIGN alignment requirement, as we'd
have to push knowledge of that throughout various code that copies data
structures around.
The only way out of the box is to make type int128 conform to the system's
alignment assumptions. Fortunately, gcc supports that via its
__attribute__(aligned()) pragma; and since we don't currently support
int128 on non-gcc-workalike compilers, we shouldn't be losing any platform
support this way.
Although we could have just done pg_attribute_aligned(MAXIMUM_ALIGNOF) and
called it a day, I did a little bit of extra work to make the code more
portable than that: it will also support int128 on compilers without
__attribute__(aligned()), if the native alignment of their 128-bit-int
type is no more than that of int64.
Add a regression test case that exercises the one known instance of the
problem, in parallel aggregation over a bigint column.
Back-patch of commit 751804998. The code known to be affected only exists
in 9.6 and later, but we do have some stuff using int128 in 9.5, so patch
back to 9.5.
Tom Lane [Tue, 14 Nov 2017 22:22:42 +0000 (17:22 -0500)]
Rearrange c.h to create a "compiler characteristics" section.
Generalize section 1 to handle stuff that is principally about the
compiler (not libraries), such as attributes, and collect stuff there
that had been dropped into various other parts of c.h. Also, push
all the gettext macros into section 8, so that section 0 is really
just inclusions rather than inclusions and random other stuff.
The primary goal here is to get pg_attribute_aligned() defined before
section 3, so that we can use it with int128. But this seems like good
cleanup anyway.
This patch just moves macro definitions around, and shouldn't result
in any changes in generated code.
Noah Misch [Sun, 12 Nov 2017 22:31:00 +0000 (14:31 -0800)]
Install Windows crash dump handler before all else.
Apart from calling write_stderr() on failure, the handler depends on no
PostgreSQL facilities. We have experienced crashes before reaching the
former call site. Given such an early crash, this change cannot hurt
and may produce a helpful dump. Absent an early crash, this change has
no effect. Back-patch to 9.3 (all supported versions).
Noah Misch [Sun, 12 Nov 2017 21:03:15 +0000 (13:03 -0800)]
Don't call pgwin32_message_to_UTF16() without CurrentMemoryContext.
PostgreSQL running as a Windows service crashed upon calling
write_stderr() before MemoryContextInit(). This fix completes work
started in 5735efee15540765315aa8c1a230575e756037f7. Messages this
early contain only ASCII bytes; if we removed the CurrentMemoryContext
requirement, the ensuing conversions would have no effect. Back-patch
to 9.3 (all supported versions).
Noah Misch [Sat, 11 Nov 2017 22:39:06 +0000 (14:39 -0800)]
Add post-2010 ecpg tests to checktcp.
This suite had been a proper superset of the regular ecpg test suite,
but the three newest tests didn't reach it. To make this less likely to
recur, delete the extra schedule file and pass the TCP-specific test on
the command line. Back-patch to 9.3 (all supported versions).
Noah Misch [Sat, 11 Nov 2017 22:33:02 +0000 (14:33 -0800)]
Make connect/test1 independent of localhost IPv6.
Since commit 868898739a8da9ab74c105b8349b7b5c711f265a, it has assumed
"localhost" resolves to both ::1 and 127.0.0.1. We gain nothing from
that assumption, and it does not hold in a default installation of Red
Hat Enterprise Linux 5. Back-patch to 9.3 (all supported versions).
Noah Misch [Sat, 11 Nov 2017 19:10:53 +0000 (11:10 -0800)]
Ignore XML declaration in xpath_internal(), for UTF8 databases.
When a value contained an XML declaration naming some other encoding,
this function interpreted UTF8 bytes as the named encoding, yielding
mojibake. xml_parse() already has similar logic. This would be
necessary but not sufficient for non-UTF8 databases, so preserve
behavior there until the xpath facility can support such databases
comprehensively. Back-patch to 9.3 (all supported versions).
Tom Lane [Fri, 10 Nov 2017 17:30:01 +0000 (12:30 -0500)]
Tighten test in contrib/bloom/t/001_wal.pl.
Make bloom WAL test compare psql output text, not just result codes;
this was evidently the intent all along, but it was mis-coded.
In passing, make sure we will notice any failure in setup steps.
Alexander Korotkov, reviewed by Michael Paquier and Masahiko Sawada
Tom Lane [Thu, 9 Nov 2017 16:00:36 +0000 (11:00 -0500)]
Revert "Allow --with-bonjour to work with non-macOS implementations of Bonjour."
Upon further review, our Bonjour code doesn't actually work with the
Avahi not-too-compatible compatibility library. While you can get it
to work on non-macOS platforms if you link to Apple's own mDNSResponder
code, there don't seem to be many people who care about that. Leaving in
the AC_SEARCH_LIBS call seems more likely to encourage people to build
broken configurations than to do anything very useful.
Hence, remove the AC_SEARCH_LIBS call and put in a warning comment instead.
Tom Lane [Wed, 8 Nov 2017 21:50:13 +0000 (16:50 -0500)]
Fix two violations of the ResourceOwnerEnlarge/Remember protocol.
The point of having separate ResourceOwnerEnlargeFoo and
ResourceOwnerRememberFoo functions is so that resource allocation
can happen in between. Doing it in some other order is just wrong.
OpenTemporaryFile() did open(), enlarge, remember, which would leak the
open file if the enlarge step ran out of memory. Because fd.c has its own
layer of resource-remembering, the consequences look like they'd be limited
to an intratransaction FD leak, but it's still not good.
IncrBufferRefCount() did enlarge, remember, incr-refcount, which would blow
up if the incr-refcount step ever failed. It was safe enough when written,
but since the introduction of PrivateRefCountHash, I think the assumption
that no error could happen there is pretty shaky.
The odds of real problems from either bug are probably small, but still,
back-patch to supported branches.
Thomas Munro and Tom Lane, per a comment from Andres Freund
Tom Lane [Tue, 7 Nov 2017 18:49:36 +0000 (13:49 -0500)]
Fix unportable usage of <ctype.h> functions.
isdigit(), isspace(), etc are likely to give surprising results if passed a
signed char. We should always cast the argument to unsigned char to avoid
that. Error in commit 63d6b97fd, found by buildfarm member gaur.
Back-patch to 9.3, like that commit.
Tom Lane [Mon, 6 Nov 2017 15:29:16 +0000 (10:29 -0500)]
Make json{b}_populate_recordset() use the right tuple descriptor.
json{b}_populate_recordset() used the tuple descriptor created from the
query-level AS clause without worrying about whether it matched the actual
input record type. If it didn't, that would usually result in a crash,
though disclosure of server memory contents seems possible as well, for a
skilled attacker capable of issuing crafted SQL commands. Instead, use
the query-supplied descriptor only when there is no input tuple to look at,
and otherwise get a tuple descriptor based on the input tuple's own type
marking. The core code will detect any type mismatch in the latter case.
Michael Paquier and Tom Lane, per a report from David Rowley.
Back-patch to 9.3 where this functionality was introduced.
Noah Misch [Mon, 6 Nov 2017 15:11:10 +0000 (07:11 -0800)]
start-scripts: switch to $PGUSER before opening $PGLOG.
By default, $PGUSER has permission to unlink $PGLOG. If $PGUSER
replaces $PGLOG with a symbolic link, the server will corrupt the
link-targeted file by appending log messages. Since these scripts open
$PGLOG as root, the attack works regardless of target file ownership.
"make install" does not install these scripts anywhere. Users having
manually installed them in the past should repeat that process to
acquire this fix. Most script users have $PGLOG writable to root only,
located in $PGDATA. Just before updating one of these scripts, such
users should rename $PGLOG to $PGLOG.old. The script will then recreate
$PGLOG with proper ownership.
Reviewed by Peter Eisentraut. Reported by Antoine Scemama.
Dean Rasheed [Mon, 6 Nov 2017 09:16:24 +0000 (09:16 +0000)]
Always require SELECT permission for ON CONFLICT DO UPDATE.
The update path of an INSERT ... ON CONFLICT DO UPDATE requires SELECT
permission on the columns of the arbiter index, but it failed to check
for that in the case of an arbiter specified by constraint name.
In addition, for a table with row level security enabled, it failed to
check updated rows against the table's SELECT policies when the update
path was taken (regardless of how the arbiter index was specified).
Backpatch to 9.5 where ON CONFLICT DO UPDATE and RLS were introduced.
Noah Misch [Mon, 6 Nov 2017 02:51:08 +0000 (18:51 -0800)]
Add a temp-install prerequisite to "check"-like targets not having one.
Makefile.global assigns this prerequisite to every target named "check",
but similar targets must mention it explicitly. Affected targets
failed, tested $PATH binaries, or tested a stale temporary installation.
The src/test/modules examples worked properly when called as "make -C
src/test/modules/$FOO check", but "make -j" allowed the test to start
before the temporary installation was in place. Back-patch to 9.5,
where commit dcae5faccab64776376d354decda0017c648bb53 introduced the
shared temp-install.
Tom Lane [Sun, 5 Nov 2017 18:47:56 +0000 (13:47 -0500)]
Release notes for 10.1, 9.6.6, 9.5.10, 9.4.15, 9.3.20, 9.2.24.
In the v10 branch, also back-patch the effects of 1ff01b390 and c29c57890
on these files, to reduce future maintenance issues. (I'd do it further
back, except that the 9.X branches differ anyway due to xlog-to-wal
link tag renaming.)
Noah Misch [Sun, 5 Nov 2017 17:25:52 +0000 (09:25 -0800)]
Ignore CatalogSnapshot when checking COPY FREEZE prerequisites.
This restores the ability, essentially lost in commit ffaa44cb559db332baeee7d25dedd74a61974203, to use COPY FREEZE under
REPEATABLE READ isolation. Back-patch to 9.4, like that commit.
Alvaro Herrera [Fri, 3 Nov 2017 16:23:13 +0000 (17:23 +0100)]
Fix BRIN summarization concurrent with extension
If a process is extending a table concurrently with some BRIN
summarization process, it is possible for the latter to miss pages added
by the former because the number of pages is computed ahead of time.
Fix by determining a fresh relation size after inserting the placeholder
tuple: any process that further extends the table concurrently will
update the placeholder tuple, while previous pages will be processed by
the heap scan.
Reported-by: Tomas Vondra Reviewed-by: Tom Lane
Author: Álvaro Herrera
Discussion: https://postgr.es/m/083d996a-4a8a-0e13-800a-851dd09ad8cc@2ndquadrant.com Backpatch-to: 9.5
Tom Lane [Thu, 2 Nov 2017 16:54:23 +0000 (12:54 -0400)]
Fix corner-case errors in brin_doupdate().
In some cases the BRIN code releases lock on an index page, and later
re-acquires lock and tries to check that the tuple it was working on is
still there. That check was a couple bricks shy of a load. It didn't
consider that the page might have turned into a "revmap" page. (The
samepage code path doesn't call brin_getinsertbuffer(), so it isn't
protected by the checks for revmap status there.) It also didn't check
whether the tuple offset was now off the end of the linepointer array.
Since commit 24992c6db the latter case is pretty common, but at least
in principle it could have occurred before that. The net result is
that concurrent updates of a BRIN index could fail with errors like
"invalid index offnum" or "inconsistent range map".
Per report from Tomas Vondra. Back-patch to 9.5, since this code is
substantially the same in all versions containing BRIN.
Alvaro Herrera [Thu, 2 Nov 2017 14:51:05 +0000 (15:51 +0100)]
Revert bogus fixes of HOT-freezing bug
It turns out we misdiagnosed what the real problem was. Revert the
previous changes, because they may have worse consequences going
forward. A better fix is forthcoming.
The simplistic test case is kept, though disabled.
pg_basebackup: Fix comparison handling of tablespace mappings on Windows
A candidate path needs to be canonicalized before being checked against
the mappings, because the mappings are also canonicalized. This is
especially relevant on Windows
Reported-by: nb <nbedxp@gmail.com>
Author: Michael Paquier <michael.paquier@gmail.com> Reviewed-by: Ashutosh Sharma <ashu.coek88@gmail.com>
Robert Haas [Sun, 29 Oct 2017 07:28:40 +0000 (12:58 +0530)]
Fix problems with the "role" GUC and parallel query.
Without this fix, dropping a role can sometimes result in parallel
query failures in sessions that have used "SET ROLE" to assume the
dropped role, even if that setting isn't active any more.
Report by Pavan Deolasee. Patch by Amit Kapila, reviewed by me.
Tom Lane [Fri, 27 Oct 2017 22:16:25 +0000 (18:16 -0400)]
Dept of second thoughts: keep aliasp_item in sync with tlistitem.
Commit d5b760ecb wasn't quite right, on second thought: if the
caller didn't ask for column names then it would happily emit
more Vars than if the caller did ask for column names. This
is surely not a good idea. Advance the aliasp_item whether or
not we're preparing a colnames list.
Tom Lane [Fri, 27 Oct 2017 21:10:21 +0000 (17:10 -0400)]
Fix crash when columns have been added to the end of a view.
expandRTE() supposed that an RTE_SUBQUERY subquery must have exactly
as many non-junk tlist items as the RTE has column aliases for it.
This was true at the time the code was written, and is still true so
far as parse analysis is concerned --- but when the function is used
during planning, the subquery might have appeared through insertion
of a view that now has more columns than it did when the outer query
was parsed. This results in a core dump if, for instance, we have
to expand a whole-row Var that references the subquery.
To avoid crashing, we can either stop expanding the RTE when we run
out of aliases, or invent new aliases for the added columns. While
the latter might be more useful, the former is consistent with what
expandRTE() does for composite-returning functions in the RTE_FUNCTION
case, so it seems like we'd better do it that way.
Per bug #14876 from Samuel Horwitz. This has been busted since commit ff1ea2173 allowed views to acquire more columns, so back-patch to all
supported branches.
Tom Lane [Fri, 27 Oct 2017 16:18:57 +0000 (12:18 -0400)]
Rethink the dependencies recorded for FieldSelect/FieldStore nodes.
On closer investigation, commits f3ea3e3e8 et al were a few bricks
shy of a load. What we need is not so much to lock down the result
type of a FieldSelect, as to lock down the existence of the column
it's trying to extract. Otherwise, we can break it by dropping that
column. The dependency on the result type is then held indirectly
through the column, and doesn't need to be recorded explicitly.
Out of paranoia, I left in the code to record a dependency on the
result type, but it's used only if we can't identify the pg_class OID
for the column. That shouldn't ever happen right now, AFAICS, but
it seems possible that in future the input node could be marked as
being of type RECORD rather than some specific composite type.
Likewise for FieldStore.
Like the previous patch, back-patch to all supported branches.
Robert Haas [Fri, 27 Oct 2017 14:04:01 +0000 (16:04 +0200)]
Fix mistaken failure to allow parallelism in corner case.
If we try to run a parallel plan in serial mode because, for example,
it's going to be scanned via a cursor, but for some reason we're
already in parallel mode (for example because an outer query is
running in parallel), we'd incorrectly try to launch workers.
Fix by adding a flag to the EState, so that we can be certain that
ExecutePlan() and ExecGather()/ExecGatherMerge() will have the same
idea about whether we are executing serially or in parallel.
Report and fix by Amit Kapila with help from Kuntal Ghosh. A few
tweaks by me.
Tom Lane [Thu, 26 Oct 2017 16:17:40 +0000 (12:17 -0400)]
Make setrefs.c match by ressortgroupref even for plain Vars.
Previously, we skipped using search_indexed_tlist_for_sortgroupref()
if the tlist expression being sought in the child plan node was merely
a Var. This is purely an optimization, based on the theory that
search_indexed_tlist_for_var() is faster, and one copy of a Var should
be as good as another. However, the GROUPING SETS patch broke the
latter assumption: grouping columns containing the "same" Var can
sometimes have different outputs, as shown in the test case added here.
So do it the hard way whenever a ressortgroupref marking exists.
(If this seems like a bottleneck, we could imagine building a tlist index
data structure for ressortgroupref values, as we do for Vars. But I'll
let that idea go until there's some evidence it's worthwhile.)
Back-patch to 9.6. The problem also exists in 9.5 where GROUPING SETS
came in, but this patch is insufficient to resolve the problem in 9.5:
there is some obscure dependency on the upper-planner-pathification
work that happened in 9.6. Given that this is such a weird corner case,
and no end users have complained about it, it doesn't seem worth the work
to develop a fix for 9.5.
Patch by me, per a report from Heikki Linnakangas. (This does not fix
Heikki's original complaint, just the follow-on one.)
Andrew Dunstan [Thu, 26 Oct 2017 14:10:37 +0000 (10:10 -0400)]
Improve gendef.pl diagnostic on failure to open sym file
There have been numerous buildfarm failures but the diagnostic is
currently silent about the reason for failure to open the file. Let's
see if we can get to the bottom of it.
Tom Lane [Wed, 25 Oct 2017 23:32:24 +0000 (19:32 -0400)]
Fix libpq to not require user's home directory to exist.
Some people like to run libpq-using applications in environments where
there's no home directory. We've broken that scenario before (cf commits 5b4067798 and bd58d9d88), and commit ba005f193 broke it again, by making
it a hard error if we fail to get the home directory name while looking
for ~/.pgpass. The previous precedent is that if we can't get the home
directory name, we should just silently act as though the file we hoped
to find there doesn't exist. Rearrange the new code to honor that.
Looking around, the service-file code added by commit 41a4e4595 had the
same disease. Apparently, that escaped notice because it only runs when
a service name has been specified, which I guess the people who use this
scenario don't do. Nonetheless, it's wrong too, so fix that case as well.
Add a comment about this policy to pqGetHomeDirectory, in the probably
vain hope of forestalling the same error in future. And upgrade the
rather miserable commenting in parseServiceInfo, too.
In passing, also back off parseServiceInfo's assumption that only ENOENT
is an ignorable error from stat() when checking a service file. We would
need to ignore at least ENOTDIR as well (cf 5b4067798), and seeing that
the far-better-tested code for ~/.pgpass treats all stat() failures alike,
I think this code ought to as well.
Per bug #14872 from Dan Watson. Back-patch the .pgpass change to v10
where ba005f193 came in. The service-file bugs are far older, so
back-patch the other changes to all supported branches.
Andrew Dunstan [Wed, 25 Oct 2017 11:34:00 +0000 (07:34 -0400)]
Process variadic arguments consistently in json functions
json_build_object and json_build_array and the jsonb equivalents did not
correctly process explicit VARIADIC arguments. They are modified to use
the new extract_variadic_args() utility function which abstracts away
the details of the call method.
Michael Paquier, reviewed by Tom Lane and Dmitry Dolgov.
Backpatch to 9.5 for the jsonb fixes and 9.4 for the json fixes, as
that's where they originated.
Andrew Dunstan [Wed, 25 Oct 2017 11:13:11 +0000 (07:13 -0400)]
Add a utility function to extract variadic function arguments
This is epecially useful in the case or "VARIADIC ANY" functions. The
caller can get the artguments and types regardless of whether or not and
explicit VARIADIC array argument has been used. The function also
provides an option to convert arguments on type "unknown" to to "text".
Michael Paquier and me, reviewed by Tom Lane.
Backpatch to 9.4 in order to support the following json bug fix.
Tom Lane [Mon, 23 Oct 2017 22:15:36 +0000 (18:15 -0400)]
Update time zone data files to tzdata release 2017c.
DST law changes in Fiji, Namibia, Northern Cyprus, Sudan, Tonga,
and Turks & Caicos Islands. Historical corrections for Alaska, Apia,
Burma, Calcutta, Detroit, Ireland, Namibia, and Pago Pago.
Tom Lane [Mon, 23 Oct 2017 21:54:09 +0000 (17:54 -0400)]
Sync our copy of the timezone library with IANA release tzcode2017c.
This is a trivial update containing only cosmetic changes. The point
is just to get back to being synced with an official release of tzcode,
rather than some ad-hoc point in their commit history, which is where
commit 47f849a3c left it.
Tom Lane [Mon, 23 Oct 2017 17:57:45 +0000 (13:57 -0400)]
Fix some oversights in expression dependency recording.
find_expr_references() neglected to record a dependency on the result type
of a FieldSelect node, allowing a DROP TYPE to break a view or rule that
contains such an expression. I think we'd omitted this case intentionally,
reasoning that there would always be a related dependency ensuring that the
DROP would cascade to the view. But at least with nested field selection
expressions, that's not true, as shown in bug #14867 from Mansur Galiev.
Add the dependency, and for good measure a dependency on the node's exposed
collation.
Likewise add a dependency on the result type of a FieldStore. I think here
the reasoning was that it'd only appear within an assignment to a field,
and the dependency on the field's column would be enough ... but having
seen this example, I think that's wrong for nested-composites cases.
Looking at nearby code, I notice we're not recording a dependency on the
exposed collation of CoerceViaIO, which seems inconsistent with our choices
for related node types. Maybe that's OK but I'm feeling suspicious of this
code today, so let's add that; it certainly can't hurt.
This patch does not do anything to protect already-existing views, only
views created after it's installed. But seeing that the issue has been
there a very long time and nobody noticed till now, that's probably good
enough.
Tom Lane [Fri, 20 Oct 2017 21:12:27 +0000 (17:12 -0400)]
Fix typcache's failure to treat ranges as container types.
Like the similar logic for arrays and records, it's necessary to examine
the range's subtype to decide whether the range type can support hashing.
We can omit checking the subtype for btree-defined operations, though,
since range subtypes are required to have those operations. (Possibly
that simplification for btree cases led us to overlook that it does
not apply for hash cases.)
This is only an issue if the subtype lacks hash support, which is not
true of any built-in range type, but it's easy to demonstrate a problem
with a range type over, eg, money: you can get a "could not identify
a hash function" failure when the planner is misled into thinking that
hash join or aggregation would work.
This was born broken, so back-patch to all supported branches.
Tom Lane [Tue, 17 Oct 2017 16:15:08 +0000 (12:15 -0400)]
Fix misparsing of non-newline-terminated pg_hba.conf files.
This back-patches the v10-cycle commit 1e5a5d03d into 9.3 - 9.6.
I had noticed at the time that that was fixing a bug, namely that
next_token() might advance *lineptr past the line-terminating '\0',
but given the lack of field complaints I too easily convinced myself
that the problem was only latent. It's not, because tokenize_file()
decides whether there's more on the line using "strlen(lineptr)".
The bug is indeed latent on a newline-terminated line, because then
the newline-stripping bit in tokenize_file() means we'll have two
or more consecutive '\0's in the buffer, masking the fact that we
accidentally advanced over the first one. But the last line in
the file might not be null-terminated, allowing the loop to see
and process garbage, as reported by Mark Jones in bug #14859.
The bug doesn't exist in <= 9.2; there next_token() is reading directly
from a file, and termination of the outer loop relies on an feof() test
not a buffer pointer check. Probably commit 7f49a67f9 can be blamed
for this bug, but I didn't track it down exactly.
Commit 1e5a5d03d does a bit more than the minimum needed to fix the
bug, but I felt the rest of it was good cleanup, so applying it all.
Tom Lane [Thu, 12 Oct 2017 19:20:04 +0000 (15:20 -0400)]
Fix AggGetAggref() so it won't lie to aggregate final functions.
If we merge the transition calculations for two different aggregates,
it's reasonable to assume that the transition function should not care
which of those Aggref structs it gets from AggGetAggref(). It is not
reasonable to make the same assumption about an aggregate final function,
however. Commit 804163bc2 broke this, as it will pass whichever Aggref
was first associated with the transition state in both cases.
This doesn't create an observable bug so far as the core system is
concerned, because the only existing uses of AggGetAggref() are in
ordered-set aggregates that happen to not pay attention to anything
but the input properties of the Aggref; and besides that, we disabled
sharing of transition calculations for OSAs yesterday. Nonetheless,
if some third-party code were using AggGetAggref() in a normal aggregate,
they would be entitled to call this a bug. Hence, back-patch the fix
to 9.6 where the problem was introduced.
In passing, improve some of the comments about transition state sharing.
Tom Lane [Thu, 12 Oct 2017 02:18:01 +0000 (22:18 -0400)]
Prevent sharing transition states between ordered-set aggregates.
This ought to work, but the built-in OSAs are not capable of coping,
because their final-functions destructively modify their transition
state (specifically, the contained tuplesort object). That was fine
when those functions were written, but commit 804163bc2 moved the
goalposts without telling orderedsetaggs.c.
We should fix the built-in OSAs to support this, but it will take
a little work, especially if we don't want to sacrifice performance
in the normal non-shared-state case. Given that it took a year after
9.6 release for anyone to notice this bug, we should not prioritize
sharable-state over nonsharable-state performance. And a proper fix
is likely to be more complicated than we'd want to back-patch, too.
Therefore, let's just put in this stop-gap patch to prevent nodeAgg.c
from choosing to use shared state for OSAs. We can revert it in HEAD
when we get a better fix.
Report from Lukas Eder, diagnosis by me, patch by David Rowley.
Back-patch to 9.6 where the problem was introduced.
Andres Freund [Wed, 11 Oct 2017 19:03:26 +0000 (12:03 -0700)]
Prevent idle in transaction session timeout from sometimes being ignored.
The previous coding in ProcessInterrupts() could lead to
idle_in_transaction_session_timeout being ignored, when
statement_timeout occurred earlier.
The problem was that ProcessInterrupts() would return before
processing the transaction timeout if QueryCancelPending was set while
QueryCancelHoldoffCount != 0 - which is the case when reading new
commands from the client. Ergo when the idle transaction timeout would
hit.
Fix that by removing the early return. Alternatively the transaction
timeout code could have been moved up, but that early return seems
like an issue that could hit other cases too.
Author: Lukas Fittl
Bug: #14821
Discussion:
https://www.postgresql.org/message-id/20170921010956.17345.61461%40wrigleys.postgresql.org
https://www.postgresql.org/message-id/CAP53PkxQnv3OWJpyNPGJYT62uY=n1=2CF_Lpc6gVOFnc0-gazw@mail.gmail.com
Backpatch: 9.6-, where idle_in_transaction_session_timeout was introduced.
Tom Lane [Wed, 11 Oct 2017 20:56:23 +0000 (16:56 -0400)]
Doc: fix missing explanation of default object privileges.
The GRANT reference page, which lists the default privileges for new
objects, failed to mention that USAGE is granted by default for data
types and domains. As a lesser sin, it also did not specify anything
about the initial privileges for sequences, FDWs, foreign servers,
or large objects. Fix that, and add a comment to acldefault() in the
probably vain hope of getting people to maintain this list in future.
Noted by Laurenz Albe, though I editorialized on the wording a bit.
Back-patch to all supported branches, since they all have this behavior.
Tom Lane [Wed, 11 Oct 2017 18:28:33 +0000 (14:28 -0400)]
Fix low-probability loss of NOTIFY messages due to XID wraparound.
Up to now async.c has used TransactionIdIsInProgress() to detect whether
a notify message's source transaction is still running. However, that
function has a quick-exit path that reports that XIDs before RecentXmin
are no longer running. If a listening backend is doing nothing but
listening, and not running any queries, there is nothing that will advance
its value of RecentXmin. Once 2 billion transactions elapse, the
RecentXmin check causes active transactions to be reported as not running.
If they aren't committed yet according to CLOG, async.c decides they
aborted and discards their messages. The timing for that is a bit tight
but it can happen when multiple backends are sending notifies concurrently.
The net symptom therefore is that a sufficiently-long-surviving
listen-only backend starts to miss some fraction of NOTIFY traffic,
but only under heavy load.
The only function that updates RecentXmin is GetSnapshotData().
A brute-force fix would therefore be to take a snapshot before
processing incoming notify messages. But that would add cycles,
as well as contention for the ProcArrayLock. We can be smarter:
having taken the snapshot, let's use that to check for running
XIDs, and not call TransactionIdIsInProgress() at all. In this
way we reduce the number of ProcArrayLock acquisitions from one
per message to one per notify interrupt; that's the same under
light load but should be a benefit under heavy load. Light testing
says that this change is a wash performance-wise for normal loads.
I looked around for other callers of TransactionIdIsInProgress()
that might be at similar risk, and didn't find any; all of them
are inside transactions that presumably have already taken a
snapshot.
Problem report and diagnosis by Marko Tiikkaja, patch by me.
Back-patch to all supported branches, since it's been like this
since 9.0.
Tom Lane [Sun, 8 Oct 2017 19:25:26 +0000 (15:25 -0400)]
Increase distance between flush requests during bulk file copies.
copy_file() reads and writes data 64KB at a time (with default BLCKSZ),
and historically has issued a pg_flush_data request after each write.
This turns out to interact really badly with macOS's new APFS file
system: a large file copy takes over 100X longer than it ought to on
APFS, as reported by Brent Dearth. While that's arguably a macOS bug,
it's not clear whether Apple will do anything about it in the near
future, and in any case experimentation suggests that issuing flushes
a bit less often can be helpful on other platforms too.
Hence, rearrange the logic in copy_file() so that flush requests are
issued once per N writes rather than every time through the loop.
I set the FLUSH_DISTANCE to 32MB on macOS (any less than that still
results in a noticeable speed degradation on APFS), but 1MB elsewhere.
In limited testing on Linux and FreeBSD, this seems slightly faster
than the previous code, and certainly no worse. It helps noticeably
on macOS even with the older HFS filesystem.
A simpler change would have been to just increase the size of the
copy buffer without changing the loop logic, but that seems likely
to trash the processor cache without really helping much.
Back-patch to 9.6 where we introduced msync() as an implementation
option for pg_flush_data(). The problem seems specific to APFS's
mmap/msync support, so I don't think we need to go further back.
Tom Lane [Fri, 6 Oct 2017 23:18:58 +0000 (19:18 -0400)]
Fix crash when logical decoding is invoked from a PL function.
The logical decoding functions do BeginInternalSubTransaction and
RollbackAndReleaseCurrentSubTransaction to clean up after themselves.
It turns out that AtEOSubXact_SPI has an unrecognized assumption that
we always need to cancel the active SPI operation in the SPI context
that surrounds the subtransaction (if there is one). That's true
when the RollbackAndReleaseCurrentSubTransaction call is coming from
the SPI-using function itself, but not when it's happening inside
some unrelated function invoked by a SPI query. In practice the
affected callers are the various PLs.
To fix, record the current subtransaction ID when we begin a SPI
operation, and clean up only if that ID is the subtransaction being
canceled.
Also, remove AtEOSubXact_SPI's assertion that it must have cleaned
up the surrounding SPI context's active tuptable. That's proven
wrong by the same test case.
Also clarify (or, if you prefer, reinterpret) the calling conventions
for _SPI_begin_call and _SPI_end_call. The memory context cleanup
in the latter means that these have always had the flavor of a matched
resource-management pair, but they weren't documented that way before.
Per report from Ben Chobot.
Back-patch to 9.4 where logical decoding came in. In principle,
the SPI changes should go all the way back, since the problem dates
back to commit 7ec1c5a86. But given the lack of field complaints
it seems few people are using internal subtransactions in this way.
So I don't feel a need to take any risks in 9.2/9.3.
Tom Lane [Fri, 6 Oct 2017 16:20:13 +0000 (12:20 -0400)]
Fix access-off-end-of-array in clog.c.
Sloppy loop coding in set_status_by_pages() resulted in fetching one array
element more than it should from the subxids[] array. The odds of this
resulting in SIGSEGV are pretty small, but we've certainly seen that happen
with similar mistakes elsewhere. While at it, we can get rid of an extra
TransactionIdToPage() calculation per loop.
Per report from David Binderman. Back-patch to all supported branches,
since this code is quite old.
Alvaro Herrera [Fri, 6 Oct 2017 15:14:42 +0000 (17:14 +0200)]
Fix traversal of half-frozen update chains
When some tuple versions in an update chain are frozen due to them being
older than freeze_min_age, the xmax/xmin trail can become broken. This
breaks HOT (and probably other things). A subsequent VACUUM can break
things in more serious ways, such as leaving orphan heap-only tuples
whose root HOT redirect items were removed. This can be seen because
index creation (or REINDEX) complain like
ERROR: XX000: failed to find parent tuple for heap-only tuple at (0,7) in table "t"
Because of relfrozenxid contraints, we cannot avoid the freezing of the
early tuples, so we must cope with the results: whenever we see an Xmin
of FrozenTransactionId, consider it a match for whatever the previous
Xmax value was.
This problem seems to have appeared in 9.3 with multixact changes,
though strictly speaking it seems unrelated.
Since 9.4 we have commit 37484ad2a "Change the way we mark tuples as
frozen", so the fix is simple: just compare the raw Xmin (still stored
in the tuple header, since freezing merely set an infomask bit) to the
Xmax. But in 9.3 we rewrite the Xmin value to FrozenTransactionId, so
the original value is lost and we have nothing to compare the Xmax with.
To cope with that case we need to compare the Xmin with FrozenXid,
assume it's a match, and hope for the best. Sadly, since you can
pg_upgrade a 9.3 instance containing half-frozen pages to newer
releases, we need to keep the old check in newer versions too, which
seems a bit brittle; I hope we can somehow get rid of that.
I didn't optimize the new function for performance. The new coding is
probably a bit slower than before, since there is a function call rather
than a straight comparison, but I'd rather have it work correctly than
be fast but wrong.
This is a followup after 20b655224249 fixed a few related problems.
Apparently, in 9.6 and up there are more ways to get into trouble, but
in 9.3 - 9.5 I cannot reproduce a problem anymore with this patch, so
there must be a separate bug.
Reported-by: Peter Geoghegan Diagnosed-by: Peter Geoghegan, Michael Paquier, Daniel Wood,
Yi Wen Wong, Álvaro
Discussion: https://postgr.es/m/CAH2-Wznm4rCrhFAiwKPWTpEw2bXDtgROZK7jWWGucXeH3D1fmA@mail.gmail.com
Alvaro Herrera [Tue, 3 Oct 2017 12:58:25 +0000 (14:58 +0200)]
Fix coding rules violations in walreceiver.c
1. Since commit b1a9bad9e744 we had pstrdup() inside a
spinlock-protected critical section; reported by Andreas Seltenreich.
Turn those into strlcpy() to stack-allocated variables instead.
Backpatch to 9.6.
2. Since commit 9ed551e0a4fd we had a pfree() uselessly inside a
spinlock-protected critical section. Tom Lane noticed in code review.
Move down. Backpatch to 9.6.
3. Since commit 64233902d22b we had GetCurrentTimestamp() (a kernel
call) inside a spinlock-protected critical section. Tom Lane noticed in
code review. Move it up. Backpatch to 9.2.
4. Since commit 1bb2558046cc we did elog(PANIC) while holding spinlock.
Tom Lane noticed in code review. Release spinlock before dying.
Backpatch to 9.2.
Tom Lane [Sun, 1 Oct 2017 16:43:47 +0000 (12:43 -0400)]
Use a longer connection timeout in pg_isready test.
Buildfarm members skink and sungazer have both recently failed this
test, with symptoms indicating that the default 3-second timeout
isn't quite enough for those very slow systems. There's no reason
to be miserly with this timeout, so boost it to 60 seconds.
Back-patch to all versions containing this test. That may be overkill,
because the failure has only been observed in the v10 branch, but
I don't feel like having to revisit this later.
Vacuum calls page-level HOT prune to remove dead HOT tuples before doing
liveness checks (HeapTupleSatisfiesVacuum) on the remaining tuples. But
concurrent transaction commit/abort may turn DEAD some of the HOT tuples
that survived the prune, before HeapTupleSatisfiesVacuum tests them.
This happens to activate the code that decides to freeze the tuple ...
which resuscitates it, duplicating data.
(This is especially bad if there's any unique constraints, because those
are now internally violated due to the duplicate entries, though you
won't know until you try to REINDEX or dump/restore the table.)
One possible fix would be to simply skip doing anything to the tuple,
and hope that the next HOT prune would remove it. But there is a
problem: if the tuple is older than freeze horizon, this would leave an
unfrozen XID behind, and if no HOT prune happens to clean it up before
the containing pg_clog segment is truncated away, it'd later cause an
error when the XID is looked up.
Fix the problem by having the tuple freezing routines cope with the
situation: don't freeze the tuple (and keep it dead). In the cases that
the XID is older than the freeze age, set the HEAP_XMAX_COMMITTED flag
so that there is no need to look up the XID in pg_clog later on.
An isolation test is included, authored by Michael Paquier, loosely
based on Daniel Wood's original reproducer. It only tests one
particular scenario, though, not all the possible ways for this problem
to surface; it be good to have a more reliable way to test this more
fully, but it'd require more work.
In message https://postgr.es/m/20170911140103.5akxptyrwgpc25bw@alvherre.pgsql
I outlined another test case (more closely matching Dan Wood's) that
exposed a few more ways for the problem to occur.
Backpatch all the way back to 9.3, where this problem was introduced by
multixact juggling. In branches 9.3 and 9.4, this includes a backpatch
of commit e5ff9fefcd50 (of 9.5 era), since the original is not
correctable without matching the coding pattern in 9.5 up.
Reported-by: Daniel Wood Diagnosed-by: Daniel Wood Reviewed-by: Yi Wen Wong, Michaël Paquier
Discussion: https://postgr.es/m/E5711E62-8FDF-4DCA-A888-C200BF6B5742@amazon.com
Tom Lane [Wed, 27 Sep 2017 21:05:53 +0000 (17:05 -0400)]
Fix behavior when converting a float infinity to numeric.
float8_numeric() and float4_numeric() failed to consider the possibility
that the input is an IEEE infinity. The results depended on the
platform-specific behavior of sprintf(): on most platforms you'd get
something like
ERROR: invalid input syntax for type numeric: "inf"
but at least on Windows it's possible for the conversion to succeed and
deliver a finite value (typically 1), due to a nonstandard output format
from sprintf and lack of syntax error checking in these functions.
Since our numeric type lacks the concept of infinity, a suitable conversion
is impossible; the best thing to do is throw an explicit error before
letting sprintf do its thing.
While at it, let's use snprintf not sprintf. Overrunning the buffer
should be impossible if sprintf does what it's supposed to, but this
is cheap insurance against a stack smash if it doesn't.
Problem reported by Taiki Kondo. Patch by me based on fix suggestion
from KaiGai Kohei. Back-patch to all supported branches.
Dean Rasheed [Wed, 27 Sep 2017 16:10:35 +0000 (17:10 +0100)]
Improve the CREATE POLICY documentation.
Provide a correct description of how multiple policies are combined,
clarify when SELECT permissions are required, mention SELECT FOR
UPDATE/SHARE, and do some other more minor tidying up.
It drops objects outside information_schema that depend on objects
inside information_schema. For example, it will drop a user-defined
view if the view query refers to information_schema.
posix_fallocate() is not quite a drop-in replacement for fallocate(),
because it is defined to return the error code as its function result,
not in "errno". I (tgl) missed this because RHEL6's version seems
to set errno as well. That is not the case on more modern Linuxen,
though, as per buildfarm results.
Aside from fixing the return-convention confusion, remove the test
for ENOSYS; we expect that glibc will mask that for posix_fallocate,
though it does not for fallocate. Keep the test for EINTR, because
POSIX specifies that as a possible result, and buildfarm results
suggest that it can happen in practice.
Tom Lane [Mon, 25 Sep 2017 20:09:20 +0000 (16:09 -0400)]
Avoid SIGBUS on Linux when a DSM memory request overruns tmpfs.
On Linux, shared memory segments created with shm_open() are backed by
swap files created in tmpfs. If the swap file needs to be extended,
but there's no tmpfs space left, you get a very unfriendly SIGBUS trap.
To avoid this, force allocation of the full request size when we create
the segment. This adds a few cycles, but none that we wouldn't expend
later anyway, assuming the request isn't hugely bigger than the actual
need.
Make this code #ifdef __linux__, because (a) there's not currently a
reason to think the same problem exists on other platforms, and (b)
applying posix_fallocate() to an FD created by shm_open() isn't very
portable anyway.
Peter Eisentraut [Fri, 22 Sep 2017 20:50:59 +0000 (16:50 -0400)]
Fix saving and restoring umask
In two cases, we set a different umask for some piece of code and
restore it afterwards. But if the contained code errors out, the umask
is not restored. So add TRY/CATCH blocks to fix that.
Tom Lane [Fri, 22 Sep 2017 04:04:21 +0000 (00:04 -0400)]
Sync our copy of the timezone library with IANA tzcode master.
This patch absorbs a few unreleased fixes in the IANA code.
It corresponds to commit 2d8b944c1cec0808ac4f7a9ee1a463c28f9cd00a
in https://github.com/eggert/tz. Non-cosmetic changes include:
TZDEFRULESTRING is updated to match current US DST practice,
rather than what it was over ten years ago. This only matters
for interpretation of POSIX-style zone names (e.g., "EST5EDT"),
and only if the timezone database doesn't include either an exact
match for the zone name or a "posixrules" entry. The latter
should not be true in any current Postgres installation, but
this could possibly matter when using --with-system-tzdata.
Get rid of a nonportable use of "++var" on a bool var.
This is part of a larger fix that eliminates some vestigial
support for consecutive leap seconds, and adds checks to
the "zic" compiler that the data files do not specify that.
Remove a couple of ancient compatibility hacks. The IANA
crew think these are obsolete, and I tend to agree. But
perhaps our buildfarm will think different.
Back-patch to all supported branches, in line with our policy
that all branches should be using current IANA code. Before v10,
this includes application of current pgindent rules, to avoid
whitespace problems in future back-patches.
Tom Lane [Thu, 21 Sep 2017 22:13:11 +0000 (18:13 -0400)]
Give a better error for duplicate entries in VACUUM/ANALYZE column list.
Previously, the code didn't think about this case and would just try to
analyze such a column twice. That would fail at the point of inserting
the second version of the pg_statistic row, with obscure error messsages
like "duplicate key value violates unique constraint" or "tuple already
updated by self", depending on context and PG version. We could allow
the case by ignoring duplicate column specifications, but it seems better
to reject it explicitly.
The bogus error messages seem like arguably a bug, so back-patch to
all supported versions.
Nathan Bossart, per a report from Michael Paquier, and whacked
around a bit by me.
Tom Lane [Wed, 20 Sep 2017 15:10:42 +0000 (11:10 -0400)]
Fix erroneous documentation about noise word GROUP.
GRANT, REVOKE, and some allied commands allow the noise word GROUP
before a role name (cf. grantee production in gram.y). This option
does not exist elsewhere, but it had nonetheless snuck into the
documentation for ALTER ROLE, ALTER USER, and CREATE SCHEMA.
Seems to be a copy-and-pasteo in commit 31eae6028, which did expand the
syntax choices here, but not in that way. Back-patch to 9.5 where that
came in.
Magnus Hagander [Wed, 20 Sep 2017 12:09:05 +0000 (14:09 +0200)]
Mention need for --no-inc-recursive in rsync command
Since rsync 3.0.0 (released in 2008), the default way to enumerate
changes was changed in a way that makes it less likely that the hardlink
sync mode works. Since the whole point of the documented procedure is
for the hardlinks to work, change our docs to suggest using the
backwards compatibility switch.
projects / postgresql / log