PostgreSQL 9.4.22 commit log

commit   : 30b1e1ac4cea9ab32f2912e503589cda09e535aa    
  
author   : Tom Lane <[email protected]>    
date     : Mon, 6 May 2019 16:54:48 -0400    
  
committer: Tom Lane <[email protected]>    
date     : Mon, 6 May 2019 16:54:48 -0400    

commit   : ffe69b4afdae8284ad3f0d4c57640f077799cfa9    
  
author   : Tom Lane <[email protected]>    
date     : Mon, 6 May 2019 12:45:59 -0400    
  
committer: Tom Lane <[email protected]>    
date     : Mon, 6 May 2019 12:45:59 -0400    

Security: CVE-2019-10129, CVE-2019-10130  

commit   : 54ff9fa588fb85f3e192bb7fe365d9db2eeed8a9    
  
author   : Peter Eisentraut <[email protected]>    
date     : Mon, 6 May 2019 14:58:53 +0200    
  
committer: Peter Eisentraut <[email protected]>    
date     : Mon, 6 May 2019 14:58:53 +0200    

Source-Git-URL: https://git.postgresql.org/git/pgtranslation/messages.git  
Source-Git-Hash: 07a92cdb0f05a078521d8464c99cd654409cd0af  

commit   : 3c09999098519da6b601df878e326eed701201ba    
  
author   : Dean Rasheed <[email protected]>    
date     : Mon, 6 May 2019 12:05:05 +0100    
  
committer: Dean Rasheed <[email protected]>    
date     : Mon, 6 May 2019 12:05:05 +0100    

In examine_variable() and examine_simple_variable(), when checking the  
user's table and column privileges to determine whether to grant  
access to the pg_statistic data, use checkAsUser for the privilege  
checks, if it's set. This will be the case if we're accessing the  
table via a view, to indicate that we should perform privilege checks  
as the view owner rather than the current user.  
  
This change makes this planner check consistent with the check in the  
executor, so the planner will be able to make use of statistics if the  
table is accessible via the view. This fixes a performance regression  
introduced by commit e2d4ef8de8, which affects queries against  
non-security barrier views in the case where the user doesn't have  
privileges on the underlying table, but the view owner does.  
  
Note that it continues to provide the same safeguards controlling  
access to pg_statistic for direct table access (in which case  
checkAsUser won't be set) and for security barrier views, because of  
the nearby checks on rte->security_barrier and rte->securityQuals.  
  
Back-patch to all supported branches because e2d4ef8de8 was.  
  
Dean Rasheed, reviewed by Jonathan Katz and Stephen Frost.  

commit   : 70200d0d74027fffa53d750546781ed067b44f98    
  
author   : Andres Freund <[email protected]>    
date     : Sun, 5 May 2019 23:31:58 -0700    
  
committer: Andres Freund <[email protected]>    
date     : Sun, 5 May 2019 23:31:58 -0700    

As the test currently causes occasional deadlocks (due to the schema  
cleanup from previous sessions potentially still running), and the  
patch from f912d7dec2 has gotten a fair bit of buildfarm coverage,  
remove the test from the test schedules. There's a set of minor  
releases coming up.  
  
Leave the tests in place, so it can manually be run using EXTRA_TESTS.  
  
For now also leave it in master, as there's no imminent release, and  
there's plenty (re-)index related work in 12. But we'll have to  
disable it before long there too, unless somebody comes up with simple  
enough fixes for the deadlock (I'm about to post a vague idea to the  
list).  
  
Discussion: https://postgr.es/m/[email protected]  
Backpatch: 9.4-11 (no master!)  

commit   : 21de9ae15935c7bd5a40aeb1b93242cc1da446cb    
  
author   : Tom Lane <[email protected]>    
date     : Sun, 5 May 2019 14:57:17 -0400    
  
committer: Tom Lane <[email protected]>    
date     : Sun, 5 May 2019 14:57:17 -0400    

commit   : 5f8e84ff47ff342e9169b20e3643819372a2f685    
  
author   : Tom Lane <[email protected]>    
date     : Thu, 2 May 2019 19:11:29 -0400    
  
committer: Tom Lane <[email protected]>    
date     : Thu, 2 May 2019 19:11:29 -0400    

Commits 3dbb317d3 et al failed under CLOBBER_CACHE_ALWAYS testing.  
Investigation showed that to reindex pg_class_oid_index, we must  
suppress accesses to the index (via SetReindexProcessing) before we call  
RelationSetNewRelfilenode, or at least before we do CommandCounterIncrement  
therein; otherwise, relcache reloads happening within the CCI may try to  
fetch pg_class rows using the index's new relfilenode value, which is as  
yet an empty file.  
  
Of course, the point of 3dbb317d3 was that that ordering didn't work  
either, because then RelationSetNewRelfilenode's own update of the index's  
pg_class row cannot access the index, should it need to.  
  
There are various ways we might have got around that, but Andres Freund  
came up with a brilliant solution: for a mapped index, we can really just  
skip the pg_class update altogether.  The only fields it was actually  
changing were relpages etc, but it was just setting them to zeroes which  
is useless make-work.  (Correct new values will be installed at the end  
of index build.)  All pg_class indexes are mapped and probably always will  
be, so this eliminates the problem by removing work rather than adding it,  
always a pleasant outcome.  Having taught RelationSetNewRelfilenode to do  
it that way, we can revert the code reordering in reindex_index.  (But  
I left the moved setup code where it was; there seems no reason why it  
has to run without use of the old index.  If you're trying to fix a  
busted pg_class index, you'll have had to disable system index use  
altogether to get this far.)  
  
Moreover, this means we don't need RelationSetIndexList at all, because  
reindex_relation's hacking to make "REINDEX TABLE pg_class" work is  
likewise now unnecessary.  We'll leave that code in place in the back  
branches, but a follow-on patch will remove it in HEAD.  
  
In passing, do some minor cleanup for commit 5c1560606 (in HEAD only),  
notably removing a duplicate newrnode assignment.  
  
Patch by me, using a core idea due to Andres Freund.  Back-patch to all  
supported branches, as 3dbb317d3 was.  
  
Discussion: https://postgr.es/m/[email protected]  

commit   : 856bc0c612bea2df5f5748a51f2cda3f3c33928d    
  
author   : Andres Freund <[email protected]>    
date     : Tue, 30 Apr 2019 17:45:32 -0700    
  
committer: Andres Freund <[email protected]>    
date     : Tue, 30 Apr 2019 17:45:32 -0700    

The tests turn out to cause deadlocks in some circumstances. Fairly  
reproducibly so with -DRELCACHE_FORCE_RELEASE  
-DCATCACHE_FORCE_RELEASE.  Some of the deadlocks may be hard to fix  
without disproportionate measures, but others probably should be fixed  
- but not in 12.  
  
We discussed removing the new tests until we can fix the issues  
underlying the deadlocks, but results from buildfarm animal  
markhor (which runs with CLOBBER_CACHE_ALWAYS) indicates that there  
might be a more severe, as of yet undiagnosed, issue (including on  
stable branches) with reindexing catalogs. The failure is:  
ERROR: could not read block 0 in file "base/16384/28025": read only 0 of 8192 bytes  
Therefore it seems advisable to keep the tests.  
  
It's not certain that running the tests in isolation removes the risk  
of deadlocks. It's possible that additional locks are needed to  
protect against a concurrent auto-analyze or such.  
  
Per discussion with Tom Lane.  
  
Discussion: https://postgr.es/m/[email protected]  
Backpatch: 9.4-, like 3dbb317d3  

commit   : 40230f0e2e3bed70eaada93b73a440221017d4d7    
  
author   : Andres Freund <[email protected]>    
date     : Tue, 30 Apr 2019 17:45:32 -0700    
  
committer: Andres Freund <[email protected]>    
date     : Tue, 30 Apr 2019 17:45:32 -0700    

Introduced in 3dbb317d3.  Fix by using the new local variable in more  
places.  
  
Reported-By: Bruce Momjian (off-list)  
Backpatch: 9.4-, like 3dbb317d3  

commit   : e7418f89f17ad351d8cbd513a104efda6d25a2bd    
  
author   : Andres Freund <[email protected]>    
date     : Mon, 29 Apr 2019 19:39:36 -0700    
  
committer: Andres Freund <[email protected]>    
date     : Mon, 29 Apr 2019 19:39:36 -0700    

When reindexing individual indexes on pg_class it was possible to  
either trigger an assertion failure:  
TRAP: FailedAssertion("!(!ReindexIsProcessingIndex(((index)->rd_id)))  
  
That's because reindex_index() called SetReindexProcessing() - which  
enables an asserts ensuring no index insertions happen into the index  
- before calling RelationSetNewRelfilenode(). That not correct for  
indexes on pg_class, because RelationSetNewRelfilenode() updates the  
relevant pg_class row, which needs to update the indexes.  
  
The are two reasons this wasn't noticed earlier. Firstly the bug  
doesn't trigger when reindexing all of pg_class, as reindex_relation  
has code "hiding" all yet-to-be-reindexed indexes. Secondly, the bug  
only triggers when the the update to pg_class doesn't turn out to be a  
HOT update - otherwise there's no index insertion to trigger the  
bug. Most of the time there's enough space, making this bug hard to  
trigger.  
  
To fix, move RelationSetNewRelfilenode() to before the  
SetReindexProcessing() (and, together with some other code, to outside  
of the PG_TRY()).  
  
To make sure the error checking intended by SetReindexProcessing() is  
more robust, modify CatalogIndexInsert() to check  
ReindexIsProcessingIndex() even when the update is a HOT update.  
  
Also add a few regression tests for REINDEXing of system catalogs.  
  
The last two improvements would have prevented some of the issues  
fixed in 5c1560606dc4c from being introduced in the first place.  
  
Reported-By: Michael Paquier  
Diagnosed-By: Tom Lane and Andres Freund  
Author: Andres Freund  
Reviewed-By: Tom Lane  
Discussion: https://postgr.es/m/[email protected]  
Backpatch: 9.4-, the bug is present in all branches  

commit   : 17947af968b82ffba7aa2bde047ddd862f7fc2f9    
  
author   : Joe Conway <[email protected]>    
date     : Sat, 27 Apr 2019 09:28:09 -0400    
  
committer: Joe Conway <[email protected]>    
date     : Sat, 27 Apr 2019 09:28:09 -0400    

As pointed out by documentation comment, the URL for PL/R  
needs to be updated to the correct current repository. Back-patch  
to all supported branches.  

commit   : 1c61ec7bb14ee0c6064f54a2ddaaedc3537db581    
  
author   : Tom Lane <[email protected]>    
date     : Fri, 26 Apr 2019 21:20:11 -0400    
  
committer: Tom Lane <[email protected]>    
date     : Fri, 26 Apr 2019 21:20:11 -0400    

Missed an inttypes.h dependency in previous patch.  Per buildfarm.  

commit   : 7f36286c2e454ded91b0bcbb738b9d7648c67390    
  
author   : Tom Lane <[email protected]>    
date     : Fri, 26 Apr 2019 19:46:26 -0400    
  
committer: Tom Lane <[email protected]>    
date     : Fri, 26 Apr 2019 19:46:26 -0400    

This corrects a small bug in zic that caused it to output an incorrect  
year-2440 transition in the Africa/Casablanca zone.  
  
More interestingly, zic has grown a "-r" option that limits the range of  
zone transitions that it will put into the output files.  That might be  
useful to people who don't like the weird GMT offsets that tzdb likes  
to use for very old dates.  It appears that for dates before the cutoff  
time specified with -r, zic will use the zone's standard-time offset  
as of the cutoff time.  So for example one might do  
  
	make install ZIC_OPTIONS='-r @-1893456000'  
  
to cause all dates before 1910-01-01 to be treated as though 1910  
standard time prevailed indefinitely far back.  (Don't blame me for  
the unfriendly way of specifying the cutoff time --- it's seconds  
since or before the Unix epoch.  You can use extract(epoch ...)  
to calculate it.)  
  
As usual, back-patch to all supported branches.  

commit   : baeb12010d2532955ed815ea31682c3d8d088cbc    
  
author   : Tom Lane <[email protected]>    
date     : Fri, 26 Apr 2019 17:56:26 -0400    
  
committer: Tom Lane <[email protected]>    
date     : Fri, 26 Apr 2019 17:56:26 -0400    

DST law changes in Palestine and Metlakatla.  
Historical corrections for Israel.  
  
Etc/UCT is now a backward-compatibility link to Etc/UTC, instead  
of being a separate zone that generates the abbreviation "UCT",  
which nowadays is typically a typo.  Postgres will still accept  
"UCT" as an input zone name, but it won't output it.  

commit   : f0c82454dcb4ef37dd360605c49a0ddcdc8b4eb8    
  
author   : Tom Lane <[email protected]>    
date     : Wed, 24 Apr 2019 14:15:45 -0400    
  
committer: Tom Lane <[email protected]>    
date     : Wed, 24 Apr 2019 14:15:45 -0400    

In sigusr1_handler, don't ignore PMSIGNAL_ADVANCE_STATE_MACHINE based  
on pmState.  The restriction is unnecessary (PostmasterStateMachine  
should work in any state), not future-proof (since it makes too many  
assumptions about why the signal might be sent), and broken even today  
because a race condition can make it necessary to respond to the signal  
in PM_WAIT_READONLY state.  The race condition seems unlikely, but  
if it did happen, a hot-standby postmaster could fail to shut down  
after receiving a smart-shutdown request.  
  
In MaybeStartWalReceiver, don't clear the WalReceiverRequested flag  
if the fork attempt fails.  Leaving it set allows us to try  
again in future iterations of the postmaster idle loop.  (The startup  
process would eventually send a fresh request signal, but this change  
may allow us to retry the fork sooner.)  
  
Remove an obsolete comment and unnecessary test in  
PostmasterStateMachine's handling of PM_SHUTDOWN_2 state.  It's not  
possible to have a live walreceiver in that state, and AFAICT has not  
been possible since commit 5e85315ea.  This isn't a live bug, but the  
false comment is quite confusing to readers.  
  
In passing, rearrange sigusr1_handler's CheckPromoteSignal tests so that  
we don't uselessly perform stat() calls that we're going to ignore the  
results of.  
  
Add some comments clarifying the behavior of MaybeStartWalReceiver;  
I very nearly rearranged it in a way that'd reintroduce the race  
condition fixed in e5d494d78.  Mea culpa for not commenting that  
properly at the time.  
  
Back-patch to all supported branches.  The PMSIGNAL_ADVANCE_STATE_MACHINE  
change is the only one of even minor significance, but we might as well  
keep this code in sync across branches.  
  
Discussion: https://postgr.es/m/[email protected]  

commit   : a82c06f4001d28c17f67c61b492f774d5e507b31    
  
author   : Michael Paquier <[email protected]>    
date     : Wed, 24 Apr 2019 09:05:37 +0900    
  
committer: Michael Paquier <[email protected]>    
date     : Wed, 24 Apr 2019 09:05:37 +0900    

This commit fixes an issue related to the way password verifiers hashed  
with MD5 are detected, leading to possibly detect that plain passwords  
are legit MD5 hashes.  A MD5-hashed entry was checked based on if its  
header uses "md5" and if the string length matches what is expected.  
Unfortunately the code never checked if the hash only used hexadecimal  
characters after the three-character prefix.  
  
Fix 9.6 down to 9.4, where this code is present.  This area of the code  
has changed in 10 and upwards with the introduction of SCRAM, which led  
to a different fix committed as of ccae190.  
  
Reported-by: Tom Lane  
Author: Michael Paquier  
Reviewed-by: Jonathan Katz  
Discussion: https://postgr.es/m/[email protected]  
Backpatch-through: 9.4  

commit   : c0bafc5e58c5043038c98bfd1591e5257202e6af    
  
author   : Tom Lane <[email protected]>    
date     : Tue, 23 Apr 2019 18:51:31 -0400    
  
committer: Tom Lane <[email protected]>    
date     : Tue, 23 Apr 2019 18:51:31 -0400    

cache_locale_time (extraction of LC_TIME-related info) had never been  
taught the lessons we previously learned about extraction of info related  
to LC_MONETARY and LC_NUMERIC.  Specifically, commit 95a777c61 taught  
PGLC_localeconv() that data coming out of localeconv() was in an encoding  
determined by the relevant locale, but we didn't realize that there's a  
similar issue with strftime().  And commit a4930e7ca hardened  
PGLC_localeconv() against errors occurring partway through, but failed  
to do likewise for cache_locale_time().  So, rearrange the latter  
function to perform encoding conversion and not risk failure while  
it's got the locales set to temporary values.  
  
This time around I also changed PGLC_localeconv() to treat it as FATAL  
if it can't restore the previous settings of the locale values.  There  
is no reason (except possibly OOM) for that to fail, and proceeding with  
the wrong locale values seems like a seriously bad idea --- especially  
on Windows where we have to also temporarily change LC_CTYPE.  Also,  
protect against the possibility that we can't identify the codeset  
reported for LC_MONETARY or LC_NUMERIC; rather than just failing,  
try to validate the data without conversion.  
  
The user-visible symptom this fixes is that if LC_TIME is set to a locale  
name that implies an encoding different from the database encoding,  
non-ASCII localized day and month names would be retrieved in the wrong  
encoding, leading to either unexpected encoding-conversion error reports  
or wrong output from to_char().  The other possible failure modes are  
unlikely enough that we've not seen reports of them, AFAIK.  
  
The encoding conversion problems do not manifest on Windows, since  
we'd already created special-case code to handle that issue there.  
  
Per report from Juan José Santamaría Flecha.  Back-patch to all  
supported versions.  
  
Juan José Santamaría Flecha and Tom Lane  
  
Discussion: https://postgr.es/m/CAC+AXB22So5aZm2vZe+MChYXec7gWfr-n-SK-iO091R0P_1Tew@mail.gmail.com  

commit   : b71f78c24ff689c92d0edbfc929e0fe798f86622    
  
author   : Bruce Momjian <[email protected]>    
date     : Wed, 17 Apr 2019 18:12:10 -0400    
  
committer: Bruce Momjian <[email protected]>    
date     : Wed, 17 Apr 2019 18:12:10 -0400    

Previously, include actions include_dir, include_if_exists, and include  
listed commented-out values which were not the defaults, which is  
inconsistent with other entries.  Instead, replace them with '', which  
is the default value.  
  
Reported-by: Emanuel Araújo  
  
Discussion: https://postgr.es/m/CAMuTAkYMx6Q27wpELDR3_v9aG443y7ZjeXu15_+1nGUjhMWOJA@mail.gmail.com  
  
Backpatch-through: 9.4  

commit   : 39a93fd294a0442292de70f2e42e9b1da1c4e3b6    
  
author   : Bruce Momjian <[email protected]>    
date     : Wed, 17 Apr 2019 18:01:01 -0400    
  
committer: Bruce Momjian <[email protected]>    
date     : Wed, 17 Apr 2019 18:01:01 -0400    

The previous paragraph trying to explain --check, --link, and no --link  
modes and the various points of failure was too complex.  Instead, use  
bullet lists and sublists.  
  
Reported-by: Daniel Gustafsson  
  
Discussion: https://postgr.es/m/qtqiv7hI87s_Xvz5ZXHCaH-1-_AZGpIDJowzlRjF3-AbCr3RhSNydM_JCuJ8DE4WZozrtxhIWmyYTbv0syKyfGB6cYMQitp9yN-NZMm-oAo=@yesql.se  
  
Backpatch-through: 9.4  

commit   : 3ef5e16c618177160bc5f95216dccab3588defdc    
  
author   : Noah Misch <[email protected]>    
date     : Fri, 12 Apr 2019 22:36:38 -0700    
  
committer: Noah Misch <[email protected]>    
date     : Fri, 12 Apr 2019 22:36:38 -0700    

postmaster startup scrutinizes any shared memory segment recorded in  
postmaster.pid, exiting if that segment matches the current data  
directory and has an attached process.  When the postmaster.pid file was  
missing, a starting postmaster used weaker checks.  Change to use the  
same checks in both scenarios.  This increases the chance of a startup  
failure, in lieu of data corruption, if the DBA does "kill -9 `head -n1  
postmaster.pid` && rm postmaster.pid && pg_ctl -w start".  A postmaster  
will no longer stop if shmat() of an old segment fails with EACCES.  A  
postmaster will no longer recycle segments pertaining to other data  
directories.  That's good for production, but it's bad for integration  
tests that crash a postmaster and immediately delete its data directory.  
Such a test now leaks a segment indefinitely.  No "make check-world"  
test does that.  win32_shmem.c already avoided all these problems.  In  
9.6 and later, enhance PostgresNode to facilitate testing.  Back-patch  
to 9.4 (all supported versions).  
  
Reviewed (in earlier versions) by Daniel Gustafsson and Kyotaro HORIGUCHI.  
  
Discussion: https://postgr.es/m/[email protected]  

commit   : 12c42a543ac80f44e02173c2d6d51ffe18de2703    
  
author   : Michael Meskes <[email protected]>    
date     : Thu, 11 Apr 2019 20:56:17 +0200    
  
committer: Michael Meskes <[email protected]>    
date     : Thu, 11 Apr 2019 20:56:17 +0200    

Patch by Liu Huailing <[email protected]>  

commit   : f4daf89582196596b947b9be96394a1f63a986dc    
  
author   : Bruce Momjian <[email protected]>    
date     : Thu, 11 Apr 2019 13:25:33 -0400    
  
committer: Bruce Momjian <[email protected]>    
date     : Thu, 11 Apr 2019 13:25:33 -0400    

Reported-by: [email protected]  
  
Discussion: https://postgr.es/m/[email protected]  
  
Backpatch-through: 9.4  

commit   : 3105844e2d9561913387db5c9e00b5161843a6a2    
  
author   : Noah Misch <[email protected]>    
date     : Tue, 9 Apr 2019 08:25:39 -0700    
  
committer: Noah Misch <[email protected]>    
date     : Tue, 9 Apr 2019 08:25:39 -0700    

The MSVC build system already did this, and commit  
617dc6d299c957e2784320382b3277ede01d9c63 used it in a second file.  
Back-patch to 9.4, like that commit.  
  
Discussion: https://postgr.es/m/CAA8=A7_1SWc3+3Z=-utQrQFOtrj_DeohRVt7diA2tZozxsyUOQ@mail.gmail.com  

commit   : 203886d3ae22495241a95207e7b62bf859c389c5    
  
author   : Noah Misch <[email protected]>    
date     : Mon, 8 Apr 2019 21:39:00 -0700    
  
committer: Noah Misch <[email protected]>    
date     : Mon, 8 Apr 2019 21:39:00 -0700    

We've long had reports of intermittent "could not reattach to shared  
memory" errors on Windows.  Buildfarm member dory fails that way when  
PGSharedMemoryReAttach() execution overlaps with creation of a thread  
for the process's "default thread pool".  Fix that by providing a second  
region to receive asynchronous allocations that would otherwise intrude  
into UsedShmemSegAddr.  In pgwin32_ReserveSharedMemoryRegion(), stop  
trying to free reservations landing at incorrect addresses; the caller's  
next step has been to terminate the affected process.  Back-patch to 9.4  
(all supported versions).  
  
Reviewed by Tom Lane.  He also did much of the prerequisite research;  
see commit bcbf2346d69f6006f126044864dd9383d50d87b4.  
  
Discussion: https://postgr.es/m/[email protected]  

commit   : c6df3a28ff40ca7124ea6c28adf2e3ff9910faee    
  
author   : Tom Lane <[email protected]>    
date     : Mon, 8 Apr 2019 16:09:07 -0400    
  
committer: Tom Lane <[email protected]>    
date     : Mon, 8 Apr 2019 16:09:07 -0400    

join_is_legal() needs to reject forming certain outer joins in cases  
where that would lead the planner down a blind alley.  However, it  
mistakenly supposed that the way to handle full joins was to treat them  
as applying the same constraints as for left joins, only to both sides.  
That doesn't work, as shown in bug #15741 from Anthony Skorski: given  
a lateral reference out of a join that's fully enclosed by a full join,  
the code would fail to believe that any join ordering is legal, resulting  
in errors like "failed to build any N-way joins".  
  
However, we don't really need to consider full joins at all for this  
purpose, because we effectively force them to be evaluated in syntactic  
order, and that order is always legal for lateral references.  Hence,  
get rid of this broken logic for full joins and just ignore them instead.  
  
This seems to have been an oversight in commit 7e19db0c0.  
Back-patch to all supported branches, as that was.  
  
Discussion: https://postgr.es/m/[email protected]  

commit   : 0777696fe346dbd3b20814acce08dd93b512afcb    
  
author   : Noah Misch <[email protected]>    
date     : Fri, 5 Apr 2019 00:00:52 -0700    
  
committer: Noah Misch <[email protected]>    
date     : Fri, 5 Apr 2019 00:00:52 -0700    

This reverts commits 2f932f71d9f2963bbd201129d7b971c8f5f077fd,  
16ee6eaf80a40007a138b60bb5661660058d0422 and  
6f0e190056fe441f7cf788ff19b62b13c94f68f3.  The buildfarm has revealed  
several bugs.  Back-patch like the original commits.  
  
Discussion: https://postgr.es/m/[email protected]  

commit   : 41547838b97b709e9ee10eecc656703b357ec86a    
  
author   : Noah Misch <[email protected]>    
date     : Wed, 3 Apr 2019 23:23:35 -0700    
  
committer: Noah Misch <[email protected]>    
date     : Wed, 3 Apr 2019 23:23:35 -0700    

Commit 2f932f71d9f2963bbd201129d7b971c8f5f077fd added code that elicits  
a warning on buildfarm member flaviventris.  Back-patch to 9.4, like  
that commit.  
  
Reported by Andres Freund.  
  
Discussion: https://postgr.es/m/[email protected]  

commit   : 624edab582886a40a2a07e4949be82b3d6fe5f1f    
  
author   : Noah Misch <[email protected]>    
date     : Wed, 3 Apr 2019 17:06:01 -0700    
  
committer: Noah Misch <[email protected]>    
date     : Wed, 3 Apr 2019 17:06:01 -0700    

When $(MODULES) and $(MODULE_big) are empty, derive the database name  
from the first element of $(REGRESS) instead of using a constant string.  
When deriving the database name from $(MODULES), use its first element  
instead of the entire list; the earlier approach would fail if any  
multi-module directory had $(REGRESS) tests.  Treat isolation suites and  
src/pl correspondingly.  Under USE_MODULE_DB=1, installcheck-world and  
check-world no longer reuse any database name in a given postmaster.  
Buildfarm members axolotl, mandrill and frogfish saw spurious "is being  
accessed by other users" failures that would not have happened without  
database name reuse.  (The CountOtherDBBackends() 5s deadline expired  
during DROP DATABASE; a backend for an earlier test suite had used the  
same database name and had not yet exited.)  Back-patch to 9.4 (all  
supported versions), except bits pertaining to isolation suites.  
  
Concept reviewed by Andrew Dunstan, Andres Freund and Tom Lane.  
  
Discussion: https://postgr.es/m/[email protected]  

commit   : 3a70b66e625707bf3f8856be2a3d0ea74d6170d7    
  
author   : Noah Misch <[email protected]>    
date     : Wed, 3 Apr 2019 17:03:46 -0700    
  
committer: Noah Misch <[email protected]>    
date     : Wed, 3 Apr 2019 17:03:46 -0700    

postmaster startup scrutinizes any shared memory segment recorded in  
postmaster.pid, exiting if that segment matches the current data  
directory and has an attached process.  When the postmaster.pid file was  
missing, a starting postmaster used weaker checks.  Change to use the  
same checks in both scenarios.  This increases the chance of a startup  
failure, in lieu of data corruption, if the DBA does "kill -9 `head -n1  
postmaster.pid` && rm postmaster.pid && pg_ctl -w start".  A postmaster  
will no longer recycle segments pertaining to other data directories.  
That's good for production, but it's bad for integration tests that  
crash a postmaster and immediately delete its data directory.  Such a  
test now leaks a segment indefinitely.  No "make check-world" test does  
that.  win32_shmem.c already avoided all these problems.  In 9.6 and  
later, enhance PostgresNode to facilitate testing.  Back-patch to 9.4  
(all supported versions).  
  
Reviewed by Daniel Gustafsson and Kyotaro HORIGUCHI.  
  
Discussion: https://postgr.es/m/[email protected]  

commit   : f3461cb8f5b505878f33d6ded15eab6f0e1993dd    
  
author   : Noah Misch <[email protected]>    
date     : Sun, 31 Mar 2019 19:32:48 -0700    
  
committer: Noah Misch <[email protected]>    
date     : Sun, 31 Mar 2019 19:32:48 -0700    

One should almost always terminate an old process, not use a manual  
removal tool like ipcrm.  Removal of the ipcclean script eleven years  
ago (39627b1ae680cba44f6e56ca5facec4fdbfe9495) and its non-replacement  
corroborate that manual shm removal is now a niche goal.  Back-patch to  
9.4 (all supported versions).  
  
Reviewed by Daniel Gustafsson and Kyotaro HORIGUCHI.  
  
Discussion: https://postgr.es/m/[email protected]  

commit   : 31737eb43ffd77de9269247dfbd11a2665e6ee57    
  
author   : Tomas Vondra <[email protected]>    
date     : Wed, 27 Mar 2019 02:39:39 +0100    
  
committer: Tomas Vondra <[email protected]>    
date     : Wed, 27 Mar 2019 02:39:39 +0100    

Relations dropped in a single transaction are tracked in a list of  
unowned relations.  With large number of dropped relations this resulted  
in poor performance at the end of a transaction, when the relations are  
removed from the singly linked list one by one.  
  
Commit b4166911 attempted to address this issue (particularly when it  
happens during recovery) by removing the relations in a reverse order,  
resulting in O(1) lookups in the list of unowned relations.  This did  
not work reliably, though, and it was possible to trigger the O(N^2)  
behavior in various ways.  
  
Instead of trying to remove the relations in a specific order with  
respect to the linked list, which seems rather fragile, switch to a  
regular doubly linked.  That allows us to remove relations cheaply no  
matter where in the list they are.  
  
As b4166911 was a bugfix, backpatched to all supported versions, do the  
same thing here.  
  
Reviewed-by: Alvaro Herrera  
Discussion: https://www.postgresql.org/message-id/flat/80c27103-99e4-1d0c-642c-d9f3b94aaa0a%402ndquadrant.com  
Backpatch-through: 9.4  

commit   : 35eaab71d1f776ecec7fd66d060b7e04987b06af    
  
author   : Tom Lane <[email protected]>    
date     : Mon, 25 Mar 2019 17:18:06 -0400    
  
committer: Tom Lane <[email protected]>    
date     : Mon, 25 Mar 2019 17:18:06 -0400    

It doesn't touch regular privileges either, but only the latter was  
explicitly stated.  
  
Discussion: https://postgr.es/m/[email protected]  

commit   : 99e414cacd063550d576cb9b1acac503157a3bce    
  
author   : Tom Lane <[email protected]>    
date     : Sun, 24 Mar 2019 15:13:21 -0400    
  
committer: Tom Lane <[email protected]>    
date     : Sun, 24 Mar 2019 15:13:21 -0400    

The code would do "PQclear(res)" twice if lo_unlink failed, evidently  
due to careless thinking about how far out a "break" would break.  
Remove the extra PQclear and adjust the loop logic so that we'll fall  
out of both levels of loop after an error, as was clearly the intent.  
  
Spotted by Coverity.  I have no idea why it took this long to notice,  
since the bug has been there since commit 67ccbb080.  Accordingly,  
back-patch to all supported branches.  

commit   : d1166af192ed0bb40ed9dc53d4e799117403233b    
  
author   : Alexander Korotkov <[email protected]>    
date     : Sun, 24 Mar 2019 15:26:45 +0300    
  
committer: Alexander Korotkov <[email protected]>    
date     : Sun, 24 Mar 2019 15:26:45 +0300    

52ac6cd2d0 added new field to ginxlogDeletePage and was backpatched to 9.4.  
That led to problems when patched postgres instance applies WAL records  
generated by non-patched one.  WAL records generated by non-patched instance  
don't contain new field, which patched one is expecting to see.  
  
Thankfully, we can distinguish patched and non-patched WAL records by their data  
size.  If we see that WAL record is generated by non-patched instance, we skip  
processing of new field.  This commit comes with some assertions.  In  
particular, if it appears that on some platform struct data size didn't change  
then static assertion will trigger.  
  
Reported-by: Simon Riggs  
Discussion: https://postgr.es/m/CANP8%2Bj%2BK4whxf7ET7%2BgO%2BG-baC3-WxqqH%3DnV4X2CgfEPA3Yu3g%40mail.gmail.com  
Author: Alexander Korotkov  
Reviewed-by: Simon Riggs, Alvaro Herrera  
Backpatch-through: 9.4  

commit   : 432356a9def4e03cb96babd396e17bbf5a59b2b1    
  
author   : Tom Lane <[email protected]>    
date     : Sat, 23 Mar 2019 17:40:19 -0400    
  
committer: Tom Lane <[email protected]>    
date     : Sat, 23 Mar 2019 17:40:19 -0400    

I failed to think about PIs starting with "xml".  We don't really  
need this check at all, so just take it out.  Oversight in  
commit 8d1dadb25 et al.  

commit   : d5e9e2330e3a4d06b6686586fde6ea332c95be61    
  
author   : Tom Lane <[email protected]>    
date     : Sat, 23 Mar 2019 17:35:05 -0400    
  
committer: Tom Lane <[email protected]>    
date     : Sat, 23 Mar 2019 17:35:05 -0400    

We don't have a src/port substitute for that function in older branches,  
so it fails on platforms lacking the function natively.  Per buildfarm.  

commit   : 8ba485422933e0ae48e8c4e1686ea59cfab75111    
  
author   : Tom Lane <[email protected]>    
date     : Sat, 23 Mar 2019 16:51:26 -0400    
  
committer: Tom Lane <[email protected]>    
date     : Sat, 23 Mar 2019 16:51:26 -0400    

In combination with the previous commit, this ensures that valid XML  
data can always be dumped and reloaded, whether it is "document"  
or "content".  
  
Discussion: https://postgr.es/m/CAN-V+g-6JqUQEQZ55Q3toXEN6d5Ez5uvzL4VR+8KtvJKj31taw@mail.gmail.com  

commit   : 78f84fe0f478142c490dcffd5eb46704b0131b9e    
  
author   : Tom Lane <[email protected]>    
date     : Sat, 23 Mar 2019 16:24:30 -0400    
  
committer: Tom Lane <[email protected]>    
date     : Sat, 23 Mar 2019 16:24:30 -0400    

Previously we were using the SQL:2003 definition, which doesn't allow  
this, but that creates a serious dump/restore gotcha: there is no  
setting of xmloption that will allow all valid XML data.  Hence,  
switch to the 2006 definition.  
  
Since libxml doesn't accept <!DOCTYPE> directives in the mode we  
use for CONTENT parsing, the implementation is to detect <!DOCTYPE>  
in the input and switch to DOCUMENT parsing mode.  This should not  
cost much, because <!DOCTYPE> should be close to the front of the  
input if it's there at all.  It's possible that this causes the  
error messages for malformed input to be slightly different than  
they were before, if said input includes <!DOCTYPE>; but that does  
not seem like a big problem.  
  
In passing, buy back a few cycles in parsing of large XML documents  
by not doing strlen() of the whole input in parse_xml_decl().  
  
Back-patch because dump/restore failures are not nice.  This change  
shouldn't break any cases that worked before, so it seems safe to  
back-patch.  
  
Chapman Flack (revised a bit by me)  
  
Discussion: https://postgr.es/m/CAN-V+g-6JqUQEQZ55Q3toXEN6d5Ez5uvzL4VR+8KtvJKj31taw@mail.gmail.com  

commit   : a1695035b3612518ee2c5dd2578b769aa6afab93    
  
author   : Tom Lane <[email protected]>    
date     : Tue, 19 Mar 2019 12:49:27 -0400    
  
committer: Tom Lane <[email protected]>    
date     : Tue, 19 Mar 2019 12:49:27 -0400    

Commit 6f6a6d8b1 introduced a delay of up to 2 seconds if we're trying  
to request a checkpoint but the checkpointer hasn't started yet (or,  
much less likely, our kill() call fails).  However buildfarm experience  
shows that that's not quite enough for slow or heavily-loaded machines.  
There's no good reason to assume that the checkpointer won't start  
eventually, so we may as well make the timeout much longer, say 60 sec.  
  
However, if the caller didn't say CHECKPOINT_WAIT, it seems like a bad  
idea to be waiting at all, much less for as long as 60 sec.  We can  
remove the need for that, and make this whole thing more robust, by  
adjusting the code so that the existence of a pending checkpoint  
request is clear from the contents of shared memory, and making sure  
that the checkpointer process will notice it at startup even if it did  
not get a signal.  In this way there's no need for a non-CHECKPOINT_WAIT  
call to wait at all; if it can't send the signal, it can nonetheless  
assume that the checkpointer will eventually service the request.  
  
A potential downside of this change is that "kill -INT" on the checkpointer  
process is no longer enough to trigger a checkpoint, should anyone be  
relying on something so hacky.  But there's no obvious reason to do it  
like that rather than issuing a plain old CHECKPOINT command, so we'll  
assume that nobody is.  There doesn't seem to be a way to preserve this  
undocumented quasi-feature without introducing race conditions.  
  
Since a principal reason for messing with this is to prevent intermittent  
buildfarm failures, back-patch to all supported branches.  
  
Discussion: https://postgr.es/m/[email protected]  

commit   : 98f8ffa18ebe5d9cda40314002432635990c5b1d    
  
author   : Tom Lane <[email protected]>    
date     : Thu, 14 Mar 2019 12:16:10 -0400    
  
committer: Tom Lane <[email protected]>    
date     : Thu, 14 Mar 2019 12:16:10 -0400    

The assertions added by commits 34ea1ab7f et al found another problem:  
set_dummy_rel_pathlist and mark_dummy_rel were failing to label  
the dummy paths they create with the correct outer_relids, in case  
the relation is necessarily parameterized due to having lateral  
references in its tlist.  It's likely that this has no user-visible  
consequences in production builds, at the moment; but still an assertion  
failure is a bad thing, so back-patch the fix.  
  
Per bug #15694 from Roman Zharkov (via Alexander Lakhin)  
and an independent report by Tushar Ahuja.  
  
Discussion: https://postgr.es/m/[email protected]  
Discussion: https://postgr.es/m/[email protected]  

commit   : e7e78f1598281a7543be563fb19c79b99826c943    
  
author   : Michael Meskes <[email protected]>    
date     : Mon, 11 Mar 2019 16:11:16 +0100    
  
committer: Michael Meskes <[email protected]>    
date     : Mon, 11 Mar 2019 16:11:16 +0100    

Patch by: "Wu, Fei" <[email protected]>  

commit   : e04bb261633dd76d6dc2e250c92f33330ec2891e    
  
author   : Tom Lane <[email protected]>    
date     : Sun, 10 Mar 2019 12:58:52 -0400    
  
committer: Tom Lane <[email protected]>    
date     : Sun, 10 Mar 2019 12:58:52 -0400    

None of the code that uses GUC values is really prepared for them to  
hold NaN, but parse_real() didn't have any defense against accepting  
such a value.  Treat it the same as a syntax error.  
  
I haven't attempted to analyze the exact consequences of setting any  
of the float GUCs to NaN, but since they're quite unlikely to be good,  
this seems like a back-patchable bug fix.  
  
Note: we don't need an explicit test for +-Infinity because those will  
be rejected by existing range checks.  I added a regression test for  
that in HEAD, but not older branches because the spelling of the value  
in the error message will be platform-dependent in branches where we  
don't always use port/snprintf.c.  
  
Discussion: https://postgr.es/m/[email protected]  

commit   : bb2da63c7e9636fea04fdd635e537737da75ad80    
  
author   : Tom Lane <[email protected]>    
date     : Sat, 9 Mar 2019 18:42:19 -0500    
  
committer: Tom Lane <[email protected]>    
date     : Sat, 9 Mar 2019 18:42:19 -0500    

Now that https://www.postgresql.org/docs/release/ is populated,  
replace the stopgap text we had under "Prior Releases" with  
a pointer to that archive.  
  
Discussion: https://postgr.es/m/[email protected]  

commit   : 81f5b32839ff9ab9b055538a4c55cf07d12ec450    
  
author   : Michael Paquier <[email protected]>    
date     : Mon, 4 Mar 2019 09:50:24 +0900    
  
committer: Michael Paquier <[email protected]>    
date     : Mon, 4 Mar 2019 09:50:24 +0900    

The implementation of readdir() in src/port/ which gets used by MSVC has  
been added in 399a36a, and since the beginning it considers all errors  
on the first file lookup as ENOENT, setting errno accordingly and  
letting the routine caller think that the directory is empty.  While  
this is normally enough for the case of the backend, this can confuse  
callers of this routine on Windows as all errors would map to the same  
behavior.  So, for example, even permission errors would be thought as  
having an empty directory, while there could be contents in it.  
  
This commit changes the error handling so as readdir() gets a behavior  
similar to native implementations: force errno=0 when seeing  
ERROR_FILE_NOT_FOUND as error and consider other errors as plain  
failures.  
  
While looking at the patch, I noticed that MinGW does not enforce  
errno=0 when looking at the first file, but it gets enforced on the next  
file lookups.  A comment related to that was incorrect in the code.  
  
Reported-by: Yuri Kurenkov  
Diagnosed-by: Yuri Kurenkov, Grigory Smolkin  
Author:	Konstantin Knizhnik  
Reviewed-by: Andrew Dunstan, Michael Paquier  
Discussion: https://postgr.es/m/[email protected]  
Backpatch-through: 9.4  

commit   : 431471e1f2a2e324b0d701c4d4fddd44f96b397a    
  
author   : Dean Rasheed <[email protected]>    
date     : Sun, 3 Mar 2019 10:58:45 +0000    
  
committer: Dean Rasheed <[email protected]>    
date     : Sun, 3 Mar 2019 10:58:45 +0000    

Previously, rewriteTargetListIU() generated a list of attribute  
numbers from the targetlist, which were passed to rewriteValuesRTE(),  
which expected them to contain the same number of entries as there are  
columns in the VALUES RTE, and to be in the same order. That was fine  
when the target relation was a table, but for an updatable view it  
could be broken in at least three different ways ---  
rewriteTargetListIU() could insert additional targetlist entries for  
view columns with defaults, the view columns could be in a different  
order from the columns of the underlying base relation, and targetlist  
entries could be merged together when assigning to elements of an  
array or composite type. As a result, when recursing to the base  
relation, the list of attribute numbers generated from the rewritten  
targetlist could no longer be relied upon to match the columns of the  
VALUES RTE. We got away with that prior to 41531e42d3 because it used  
to always be the case that rewriteValuesRTE() did nothing for the  
underlying base relation, since all DEFAULTS had already been replaced  
when it was initially invoked for the view, but that was incorrect  
because it failed to apply defaults from the base relation.  
  
Fix this by examining the targetlist entries more carefully and  
picking out just those that are simple Vars referencing the VALUES  
RTE. That's sufficient for the purposes of rewriteValuesRTE(), which  
is only responsible for dealing with DEFAULT items in the VALUES  
RTE. Any DEFAULT item in the VALUES RTE that doesn't have a matching  
simple-Var-assignment in the targetlist is an error which we complain  
about, but in theory that ought to be impossible.  
  
Additionally, move this code into rewriteValuesRTE() to give a clearer  
separation of concerns between the 2 functions. There is no need for  
rewriteTargetListIU() to know about the details of the VALUES RTE.  
  
While at it, fix the comment for rewriteValuesRTE() which claimed that  
it doesn't support array element and field assignments --- that hasn't  
been true since a3c7a993d5 (9.6 and later).  
  
Back-patch to all supported versions, with minor differences for the  
pre-9.6 branches, which don't support array element and field  
assignments to the same column in multi-row VALUES lists.  
  
Reviewed by Amit Langote.  
  
Discussion: https://postgr.es/m/[email protected]  

commit   : 00382f373239feff9dacc99dd2e5dace50da60de    
  
author   : Michael Paquier <[email protected]>    
date     : Thu, 28 Feb 2019 11:02:40 +0900    
  
committer: Michael Paquier <[email protected]>    
date     : Thu, 28 Feb 2019 11:02:40 +0900    

Reflecting an updated parameter value requires a server restart, which  
was not mentioned in the documentation and in postgresql.conf.sample.  
  
Reported-by: Thomas Poty  
Discussion: https://postgr.es/m/[email protected]  

commit   : 53c2bb78db9f9bb47de14d61fc8b2a71cf1052ca    
  
author   : Tom Lane <[email protected]>    
date     : Sun, 24 Feb 2019 12:51:51 -0500    
  
committer: Tom Lane <[email protected]>    
date     : Sun, 24 Feb 2019 12:51:51 -0500    

The Bison documentation clearly states that a semicolon is required  
after every grammar rule, and our scripts that generate ecpg's  
grammar from the backend's implicitly assumed this is true.  But it  
turns out that only ancient versions of Bison actually enforce that.  
There have been a couple of rules without trailing semicolons in  
gram.y for some time, and as a consequence, ecpg's grammar was faulty  
and produced wrong output for the affected statements.  
  
To fix, add the missing semis, and add some cross-checks to ecpg's  
scripts so that they'll bleat if we mess this up again.  
  
The cases that were broken were:  
* "SET variable = DEFAULT" (but not "SET variable TO DEFAULT"),  
  as well as allied syntaxes such as ALTER SYSTEM SET ... DEFAULT.  
  These produced syntactically invalid output that the server  
  would reject.  
* Multiple type names in DROP TYPE/DOMAIN commands.  Only the  
  first type name would be listed in the emitted command.  
  
Per report from Daisuke Higuchi.  Back-patch to all supported versions.  
  
Discussion: https://postgr.es/m/1803D792815FC24D871C00D17AE95905DB51CE@g01jpexmbkw24  

commit   : ede6b19624d1836635d8bd2c8cdc6a694d8ff678    
  
author   : Thomas Munro <[email protected]>    
date     : Sun, 24 Feb 2019 23:59:26 +1300    
  
committer: Thomas Munro <[email protected]>    
date     : Sun, 24 Feb 2019 23:59:26 +1300    

Previously, we tolerated EBADF as a way for the operating system to  
indicate that it doesn't support fsync() on a directory.  Tolerate  
EINVAL too, for older versions of Linux CIFS.  
  
Bug #15636.  Back-patch all the way.  
  
Reported-by: John Klann  
Discussion: https://postgr.es/m/[email protected]  

commit   : 99a1554a2680d25f0b54d4209ccfc76c443df6e3    
  
author   : Tom Lane <[email protected]>    
date     : Fri, 22 Feb 2019 12:23:00 -0500    
  
committer: Tom Lane <[email protected]>    
date     : Fri, 22 Feb 2019 12:23:00 -0500    

In the case where inheritance_planner() finds that every table has  
been excluded by constraints, it thought it could get away with  
making a plan consisting of just a dummy Result node.  While certainly  
there's no updating or deleting to be done, this had two user-visible  
problems: the plan did not report the correct set of output columns  
when a RETURNING clause was present, and if there were any  
statement-level triggers that should be fired, it didn't fire them.  
  
Hence, rather than only generating the dummy Result, we need to  
stick a valid ModifyTable node on top, which requires a tad more  
effort here.  
  
It's been broken this way for as long as inheritance_planner() has  
known about deleting excluded subplans at all (cf commit 635d42e9c),  
so back-patch to all supported branches.  
  
Amit Langote and Tom Lane, per a report from Petr Fedorov.  
  
Discussion: https://postgr.es/m/[email protected]  

commit   : 5a73edf050ed6740fc085cad05a2e7af9fb1f06e    
  
author   : Dean Rasheed <[email protected]>    
date     : Wed, 20 Feb 2019 08:19:55 +0000    
  
committer: Dean Rasheed <[email protected]>    
date     : Wed, 20 Feb 2019 08:19:55 +0000    

INSERT ... VALUES for a single VALUES row is implemented differently  
from a multi-row VALUES list, which causes inconsistent behaviour in  
the way that DEFAULT items are handled. In particular, when inserting  
into an auto-updatable view on top of a table with a column default, a  
DEFAULT item in a single VALUES row gets correctly replaced with the  
table column's default, but for a multi-row VALUES list it is replaced  
with NULL.  
  
Fix this by allowing rewriteValuesRTE() to leave DEFAULT items in the  
VALUES list untouched if the target relation is an auto-updatable view  
and has no column default, deferring DEFAULT-expansion until the query  
against the base relation is rewritten. For all other types of target  
relation, including tables and trigger- and rule-updatable views, we  
must continue to replace DEFAULT items with NULL in the absence of a  
column default.  
  
This is somewhat complicated by the fact that if an auto-updatable  
view has DO ALSO rules attached, the VALUES lists for the product  
queries need to be handled differently from the original query, since  
the product queries need to act like rule-updatable views whereas the  
original query has auto-updatable view semantics.  
  
Back-patch to all supported versions.  
  
Reported by Roger Curley (bug #15623). Patch by Amit Langote and me.  
  
Discussion: https://postgr.es/m/[email protected]  

commit   : 2ad57e9e9faf5e8a6fdec048636581df7210478f    
  
author   : Michael Paquier <[email protected]>    
date     : Wed, 20 Feb 2019 12:32:23 +0900    
  
committer: Michael Paquier <[email protected]>    
date     : Wed, 20 Feb 2019 12:32:23 +0900    

When building an initial slot snapshot, snapshots are marked with  
historic MVCC snapshots as type with the marker field being set in  
SnapBuildBuildSnapshot() but not overriden in SnapBuildExportSnapshot().  
Existing callers of SnapBuildBuildSnapshot() do not care about the type  
of snapshot used, but extensions calling it actually may, as reported.  
  
Author: Antonin Houska  
Reviewed-by: Álvaro Herrera, Michael Paquier  
Discussion: https://postgr.es/m/23215.1527665193@localhost  
Backpatch-through: 9.4  

commit   : 64f6a65a00b0b6d768fc3fc49047524f4f99a54d    
  
author   : Joe Conway <[email protected]>    
date     : Sun, 17 Feb 2019 13:14:29 -0500    
  
committer: Joe Conway <[email protected]>    
date     : Sun, 17 Feb 2019 13:14:29 -0500    

The dblink documentation claims that an empty string is returned if there  
has been no error, however OK is actually returned in that case. Also,  
clarify that an async error may not be seen unless dblink_is_busy() or  
dblink_get_result() have been called first.  
  
Backpatch to all supported branches.  
  
Reported-by: realyota  
Backpatch-through: 9.4  
Discussion: https://postgr.es/m/[email protected]  

commit   : 9fdc49d08fe405f0503f93849844a73517bd5cbd    
  
author   : Tom Lane <[email protected]>    
date     : Sun, 17 Feb 2019 12:37:32 -0500    
  
committer: Tom Lane <[email protected]>    
date     : Sun, 17 Feb 2019 12:37:32 -0500    

We should logically have allowed this case when we allowed zero-column  
tables, but it was overlooked.  
  
Although this might be thought a feature addition, it's really a bug  
fix, because it was possible to create a zero-column view via  
the convert-table-to-view code path, and then you'd have a situation  
where dump/reload would fail.  Hence, back-patch to all supported  
branches.  
  
Arrange the added test cases to provide coverage of the related  
pg_dump code paths (since these views will be dumped and reloaded  
during the pg_upgrade regression test).  I also made them test  
the case where pg_dump has to postpone the view rule into post-data,  
which disturbingly had no regression coverage before.  
  
Report and patch by Ashutosh Sharma (test case by me)  
  
Discussion: https://postgr.es/m/CAE9k0PkmHdeSaeZt2ujnb_cKucmK3sDDceDzw7+d5UZoNJPYOg@mail.gmail.com  

commit   : bd195071fd2be49392bf1993397f638d96315ee0    
  
author   : Thomas Munro <[email protected]>    
date     : Fri, 15 Feb 2019 10:19:11 +1300    
  
committer: Thomas Munro <[email protected]>    
date     : Fri, 15 Feb 2019 10:19:11 +1300    

DSM handle values can be reused as soon as the underlying shared memory  
object has been destroyed.  That means that for a brief moment we  
might have two DSM slots with the same handle.  While trying to attach,  
if we encounter a slot with refcnt == 1, meaning that it is currently  
being destroyed, we should continue our search in case the same handle  
exists in another slot.  
  
The race manifested as a rare "dsa_area could not attach to segment"  
error, and was more likely in 10 and 11 due to the lack of distinct  
seed for random() in parallel workers.  It was made very unlikely in  
in master by commit 197e4af9, and older releases don't usually create  
new DSM segments in background workers so it was also unlikely there.  
  
This fixes the root cause of bug report #15585, in which the error  
could also sometimes result in a self-deadlock in the error path.  
It's not yet clear if further changes are needed to avoid that failure  
mode.  
  
Back-patch to 9.4, where dsm.c arrived.  
  
Author: Thomas Munro  
Reported-by: Justin Pryzby, Sergei Kornilov  
Discussion: https://postgr.es/m/[email protected]  
Discussion: https://postgr.es/m/[email protected]  

commit   : 350cdcd5e6dd505454435af8d7640a4b5042fcfd    
  
author   : Alvaro Herrera <[email protected]>    
date     : Tue, 12 Feb 2019 18:42:37 -0300    
  
committer: Alvaro Herrera <[email protected]>    
date     : Tue, 12 Feb 2019 18:42:37 -0300    

Ever since its birth, ReorderBufferBuildTupleCidHash() has contained an  
assertion that a catalog tuple cannot change Cmax after acquiring one.  But  
that's wrong: if a subtransaction executes DDL that affects that catalog  
tuple, and later aborts and another DDL affects the same tuple, it will  
change Cmax.  Relax the assertion to merely verify that the Cmax remains  
valid and monotonically increasing, instead.  
  
Add a test that tickles the relevant code.  
  
Diagnosed by, and initial patch submitted by: Arseny Sher  
Co-authored-by: Arseny Sher  
Discussion: https://postgr.es/m/874l9p8hyw.fsf@ars-thinkpad  

commit   : 42baa60f6bc70cfffcba6a89a4b7a8b0a929b54d    
  
author   : Tom Lane <[email protected]>    
date     : Tue, 12 Feb 2019 01:12:52 -0500    
  
committer: Tom Lane <[email protected]>    
date     : Tue, 12 Feb 2019 01:12:52 -0500    

It's pretty unhelpful to report the wrong file name in a complaint  
about syscall failure, but SnapBuildSerialize managed to do that twice  
in a span of 50 lines.  Also fix half a dozen missing or poorly-chosen  
errcode assignments; that's mostly cosmetic, but still wrong.  
  
Noted while studying recent failures on buildfarm member nightjar.  
I'm not sure whether those reports are actually giving the wrong  
filename, because there are two places here with identically  
spelled error messages.  The other one is specifically coded not  
to report ENOENT, but if it's this one, how could we be getting  
ENOENT from open() with O_CREAT?  Need to sit back and await results.  
  
However, these ereports are clearly broken from birth, so back-patch.