PostgreSQL 9.6.20 (upcoming) commit log

Use factorial rather than numeric_fac in create_operator.sql.

commit   : 1e00333ffa2eebd4cd76526dbd087bee3b96a015    
  
author   : Tom Lane <tgl@sss.pgh.pa.us>    
date     : Fri, 18 Sep 2020 18:03:44 -0400    
  
committer: Tom Lane <tgl@sss.pgh.pa.us>    
date     : Fri, 18 Sep 2020 18:03:44 -0400    

Click here for diff

These two SQL functions are aliases for the same C function, so this  
change has no semantic effect.  However, because we dropped the  
numeric_fac alias in HEAD (commit 76f412ab3), operator definitions  
based on that one don't port forward, causing problems for cross-version  
upgrade tests based on the regression database.  
  
Patch all active back branches to dodge the problem.  
  
Discussion: https://postgr.es/m/449144.1600439950@sss.pgh.pa.us  

M src/test/regress/expected/create_operator.out
M src/test/regress/sql/create_operator.sql

Fix race in test of pg_switch_wal().

commit   : e09391a0a042a631de05faa195aea86acc66ba43    
  
author   : Noah Misch <noah@leadboat.com>    
date     : Sun, 13 Sep 2020 23:13:44 -0700    
  
committer: Noah Misch <noah@leadboat.com>    
date     : Sun, 13 Sep 2020 23:13:44 -0700    

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The test failed when something added WAL between pg_switch_wal() and  
pg_current_wal_lsn(), seen on buildfarm members hornet and sungazer.  
Fix v10, v9.6 and v9.5 by making this code mirror its v13+ counterpart.  
v12 and v11 lack a counterpart.  

M src/test/recovery/t/020_archive_status.pl

Use the properly transformed RangeVar for expandTableLikeClause().

commit   : 1a9c93ec3b9ae2766b60e97957d07028e2828796    
  
author   : Tom Lane <tgl@sss.pgh.pa.us>    
date     : Sun, 13 Sep 2020 12:51:21 -0400    
  
committer: Tom Lane <tgl@sss.pgh.pa.us>    
date     : Sun, 13 Sep 2020 12:51:21 -0400    

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transformCreateStmt() adjusts the transformed statement's RangeVar  
to specify the target schema explicitly, for the express reason  
of making sure that auxiliary statements derived by parse  
transformation operate on the right table.  But the refactoring  
I did in commit 502898192 got this wrong and passed the untransformed  
RangeVar to expandTableLikeClause().  This could lead to assertion  
failures or weird misbehavior if the wrong table was accessed.  
  
Per report from Alexander Lakhin.  Like the previous patch, back-patch  
to all supported branches.  
  
Discussion: https://postgr.es/m/05051f9d-b32b-cb35-6735-0e9f2ab86b5f@gmail.com  

M src/backend/tcop/utility.c
M src/test/regress/expected/create_table_like.out
M src/test/regress/sql/create_table_like.sql

Use _exit(2) for SIGQUIT during ProcessStartupPacket, too.

commit   : dc71c640985fd07b2e2ff3df7e57752a44e828ed    
  
author   : Tom Lane <tgl@sss.pgh.pa.us>    
date     : Thu, 10 Sep 2020 12:06:26 -0400    
  
committer: Tom Lane <tgl@sss.pgh.pa.us>    
date     : Thu, 10 Sep 2020 12:06:26 -0400    

Click here for diff

Bring the signal handling for startup-packet collection into line  
with the policy established in commits bedadc732 and 8e19a8264,  
namely don't risk running atexit callbacks when handling SIGQUIT.  
  
Ideally, we'd not do so for SIGTERM or timeout interrupts either,  
but that change seems a bit too risky for the back branches.  
For now, just improve the comments in this area to describe the risk.  
  
Also relocate where BackendInitialize re-disables these interrupts,  
to minimize the code span where they're active.  This doesn't buy  
a whole lot of safety, but it can't hurt.  
  
In passing, rename startup_die() to remove confusion about whether  
it is for the startup process.  
  
Like the previous commits, back-patch to all supported branches.  
  
Discussion: https://postgr.es/m/1850884.1599601164@sss.pgh.pa.us  

M src/backend/postmaster/postmaster.c

Fix title in reference section

commit   : 4f737ca15b92abd4081cf400da2d4498154ae106    
  
author   : Magnus Hagander <magnus@hagander.net>    
date     : Thu, 10 Sep 2020 14:15:26 +0200    
  
committer: Magnus Hagander <magnus@hagander.net>    
date     : Thu, 10 Sep 2020 14:15:26 +0200    

Click here for diff

Reported-by: Robert Kahlert  
Author: Daniel Gustafsson  

M doc/src/sgml/biblio.sgml

doc: Fix some grammar and inconsistencies

commit   : a4c0dbc447c7c42e1483e2d3bcc0856a5b9ba5dd    
  
author   : Michael Paquier <michael@paquier.xyz>    
date     : Thu, 10 Sep 2020 15:51:00 +0900    
  
committer: Michael Paquier <michael@paquier.xyz>    
date     : Thu, 10 Sep 2020 15:51:00 +0900    

Click here for diff

Some comments are fixed while on it.  
  
Author: Justin Pryzby  
Discussion: https://postgr.es/m/20200818171702.GK17022@telsasoft.com  
Backpatch-through: 9.6  

M doc/src/sgml/logicaldecoding.sgml
M doc/src/sgml/sources.sgml
M src/backend/storage/lmgr/proc.c

Make archiver's SIGQUIT handler exit via _exit().

commit   : b2eaddd9b00acad80d634ec671235a080269bd72    
  
author   : Tom Lane <tgl@sss.pgh.pa.us>    
date     : Wed, 9 Sep 2020 15:32:34 -0400    
  
committer: Tom Lane <tgl@sss.pgh.pa.us>    
date     : Wed, 9 Sep 2020 15:32:34 -0400    

Click here for diff

Commit 8e19a8264 changed the SIGQUIT handlers of almost all server  
processes not to run atexit callbacks.  The archiver process was  
skipped, perhaps because it's not connected to shared memory; but  
it's just as true here that running atexit callbacks in a signal  
handler is unsafe.  So let's make it work like the rest.  
  
In HEAD and v13, we can use the common SignalHandlerForCrashExit  
handler.  Before that, just tweak pgarch_exit to use _exit(2)  
explicitly.  
  
Like the previous commit, back-patch to all supported branches.  
  
Kyotaro Horiguchi, back-patching by me  
  
Discussion: https://postgr.es/m/1850884.1599601164@sss.pgh.pa.us  

M src/backend/postmaster/pgarch.c

Use return instead of exit() in configure

commit   : 27acbd51e60c98cba6441d7a88210a1c33bf9db4    
  
author   : Peter Eisentraut <peter@eisentraut.org>    
date     : Tue, 8 Sep 2020 10:09:43 +0200    
  
committer: Peter Eisentraut <peter@eisentraut.org>    
date     : Tue, 8 Sep 2020 10:09:43 +0200    

Click here for diff

Using exit() requires stdlib.h, which is not included.  Use return  
instead.  Also add return type for main().  
  
Reviewed-by: Heikki Linnakangas <hlinnaka@iki.fi>  
Reviewed-by: Thomas Munro <thomas.munro@enterprisedb.com>  
  
Backpatched because Apple macOS 10.16/11 (Big Sur) compiler makes  
calling undeclared functions an error, so these configure tests would  
fail.  
  
Reported-by: Thomas Gilligan <thomas.gilligan@icloud.com>  
Reported-by: Jesse Zhang <sbjesse@gmail.com>  
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>  
Discussion: https://www.postgresql.org/message-id/flat/09A4B554-82B1-4536-B191-2461342EE0BB%40icloud.com  

M config/c-compiler.m4
M config/c-library.m4
M configure

Fix misleading error message about inconsistent moving-aggregate types.

commit   : 2939f613fa91f12b43d51eb8c4e595d5164e5254    
  
author   : Tom Lane <tgl@sss.pgh.pa.us>    
date     : Sun, 6 Sep 2020 12:55:13 -0400    
  
committer: Tom Lane <tgl@sss.pgh.pa.us>    
date     : Sun, 6 Sep 2020 12:55:13 -0400    

Click here for diff

We reported the wrong types when complaining that an aggregate's  
moving-aggregate implementation is inconsistent with its regular  
implementation.  
  
This was wrong since the feature was introduced, so back-patch  
to all supported branches.  
  
Jeff Janes  
  
Discussion: https://postgr.es/m/CAMkU=1x808LH=LPhZp9mNSP0Xd1xDqEd+XeGcvEe48dfE6xV=A@mail.gmail.com  

M src/backend/catalog/pg_aggregate.c

Remove useless lstat() call in pg_rewind.

commit   : 1f8c163c5acdef34dff14615337332cecc21d70b    
  
author   : Tom Lane <tgl@sss.pgh.pa.us>    
date     : Sun, 6 Sep 2020 11:50:41 -0400    
  
committer: Tom Lane <tgl@sss.pgh.pa.us>    
date     : Sun, 6 Sep 2020 11:50:41 -0400    

Click here for diff

This is duplicative of an lstat that was just done by the calling  
function (traverse_datadir), besides which we weren't really doing  
anything with the results.  There's not much point in checking to  
see if someone removed the file since the previous lstat, since the  
FILE_ACTION_REMOVE code would have to deal with missing-file cases  
anyway.  Moreover, the "exists = false" assignment was a dead store;  
nothing was done with that value later.  
  
A syscall saved is a syscall earned, so back-patch to 9.5  
where this code was introduced.  
  
Discussion: https://postgr.es/m/1221796.1599329320@sss.pgh.pa.us  

M src/bin/pg_rewind/filemap.c

C comment: correct use of 64-"byte" cache line size

commit   : 7f79f9582185eb7086ac3c59fa79b47a37cd7d7a    
  
author   : Bruce Momjian <bruce@momjian.us>    
date     : Fri, 4 Sep 2020 13:27:52 -0400    
  
committer: Bruce Momjian <bruce@momjian.us>    
date     : Fri, 4 Sep 2020 13:27:52 -0400    

Click here for diff

Reported-by: Kelly Min  
  
Discussion: https://postgr.es/m/CAPSbxatOiQO90LYpSC3+svAU9-sHgDfEP4oFhcEUt_X=DqFA9g@mail.gmail.com  
  
Backpatch-through: 9.5  

M src/include/storage/buf_internals.h

Fix rare deadlock failure in create_am regression test.

commit   : b2fcaed66a4aa88331b375409ef208b12f97c144    
  
author   : Tom Lane <tgl@sss.pgh.pa.us>    
date     : Fri, 4 Sep 2020 12:40:28 -0400    
  
committer: Tom Lane <tgl@sss.pgh.pa.us>    
date     : Fri, 4 Sep 2020 12:40:28 -0400    

Click here for diff

The "DROP ACCESS METHOD gist2" test will require locking the index  
to be dropped and then its table; while most ordinary operations  
lock a table first then its index.  While no concurrent test scripts  
should be touching fast_emp4000, autovacuum might chance to be  
processing that table when the DROP runs, resulting in a deadlock  
failure.  This is pretty rare but we see it in the buildfarm from  
time to time.  
  
To fix, acquire a lock on fast_emp4000 before issuing the DROP.  
  
Since the point of the exercise is mostly to prevent buildfarm  
failures, back-patch to 9.6 where this test was introduced.  
  
Discussion: https://postgr.es/m/839004.1599185607@sss.pgh.pa.us  

M src/test/regress/expected/create_am.out
M src/test/regress/sql/create_am.sql

Avoid lockup of a parallel worker when reporting a long error message.

commit   : 2500e51e7bdc6c4f01312db276d3460644684112    
  
author   : Tom Lane <tgl@sss.pgh.pa.us>    
date     : Thu, 3 Sep 2020 16:52:09 -0400    
  
committer: Tom Lane <tgl@sss.pgh.pa.us>    
date     : Thu, 3 Sep 2020 16:52:09 -0400    

Click here for diff

Because sigsetjmp() will restore the initial state with signals blocked,  
the code path in bgworker.c for reporting an error and exiting would  
execute that way.  Usually this is fairly harmless; but if a parallel  
worker had an error message exceeding the shared-memory communication  
buffer size (16K) it would lock up, because it would wait for a  
resume-sending signal from its parallel leader which it would never  
detect.  
  
To fix, just unblock signals at the appropriate point.  
  
This can be shown to fail back to 9.6.  The lack of parallel query  
infrastructure makes it difficult to provide a simple test case for  
9.5; but I'm pretty sure the issue exists in some form there as well,  
so apply the code change there too.  
  
Vignesh C, reviewed by Bharath Rupireddy, Robert Haas, and myself  
  
Discussion: https://postgr.es/m/CALDaNm1d1hHPZUg3xU4XjtWBOLCrA+-2cJcLpw-cePZ=GgDVfA@mail.gmail.com  

M src/backend/postmaster/bgworker.c
M src/test/regress/expected/select_parallel.out
M src/test/regress/sql/select_parallel.sql

doc: clarify that max_wal_size is "during" checkpoints

commit   : 34071aa1a23a949eecd49c6c765e14bf057cacb0    
  
author   : Bruce Momjian <bruce@momjian.us>    
date     : Tue, 1 Sep 2020 17:00:09 -0400    
  
committer: Bruce Momjian <bruce@momjian.us>    
date     : Tue, 1 Sep 2020 17:00:09 -0400    

Click here for diff

Previous wording was "between".  
  
Reported-by: Pavel Luzanov  
  
Discussion: https://postgr.es/m/26906a54-d7cb-2f8e-eed7-e31660024694@postgrespro.ru  
  
Backpatch-through: 9.5  

M doc/src/sgml/config.sgml

Teach libpq to handle arbitrary-length lines in .pgpass files.

commit   : ba23174dd9163b9ebc48791f57e45fae727f8922    
  
author   : Tom Lane <tgl@sss.pgh.pa.us>    
date     : Tue, 1 Sep 2020 13:14:44 -0400    
  
committer: Tom Lane <tgl@sss.pgh.pa.us>    
date     : Tue, 1 Sep 2020 13:14:44 -0400    

Click here for diff

Historically there's been a hard-wired assumption here that no line of  
a .pgpass file could be as long as NAMEDATALEN*5 bytes.  That's a bit  
shaky to start off with, because (a) there's no reason to suppose that  
host names fit in NAMEDATALEN, and (b) this figure fails to allow for  
backslash escape characters.  However, it fails completely if someone  
wants to use a very long password, and we're now hearing reports of  
people wanting to use "security tokens" that can run up to several  
hundred bytes.  Another angle is that the file is specified to allow  
comment lines, but there's no reason to assume that long comment lines  
aren't possible.  
  
Rather than guessing at what might be a more suitable limit, let's  
replace the fixed-size buffer with an expansible PQExpBuffer.  That  
adds one malloc/free cycle to the typical use-case, but that's surely  
pretty cheap relative to the I/O this code has to do.  
  
Also, add TAP test cases to exercise this code, because there was no  
test coverage before.  
  
This reverts most of commit 2eb3bc588, as there's no longer a need for  
a warning message about overlength .pgpass lines.  (I kept the explicit  
check for comment lines, though.)  
  
In HEAD and v13, this also fixes an oversight in 74a308cf5: there's not  
much point in explicit_bzero'ing the line buffer if we only do so in two  
of the three exit paths.  
  
Back-patch to all supported branches, except that the test case only  
goes back to v10 where src/test/authentication/ was added.  
  
Discussion: https://postgr.es/m/4187382.1598909041@sss.pgh.pa.us  

M src/interfaces/libpq/fe-connect.c

doc: add commas after 'i.e.' and 'e.g.'

commit   : 5394b87a30ce1abd65aee3d2ba339135aa58c920    
  
author   : Bruce Momjian <bruce@momjian.us>    
date     : Mon, 31 Aug 2020 18:33:36 -0400    
  
committer: Bruce Momjian <bruce@momjian.us>    
date     : Mon, 31 Aug 2020 18:33:36 -0400    

Click here for diff

This follows the American format,  
https://jakubmarian.com/comma-after-i-e-and-e-g/. There is no intention  
of requiring this format for future text, but making existing text  
consistent every few years makes sense.  
  
Discussion: https://postgr.es/m/20200825183619.GA22369@momjian.us  
  
Backpatch-through: 9.5  

M doc/src/sgml/config.sgml
M doc/src/sgml/datatype.sgml
M doc/src/sgml/ddl.sgml
M doc/src/sgml/docguide.sgml
M doc/src/sgml/ecpg.sgml
M doc/src/sgml/extend.sgml
M doc/src/sgml/func.sgml
M doc/src/sgml/high-availability.sgml
M doc/src/sgml/indexam.sgml
M doc/src/sgml/install-windows.sgml
M doc/src/sgml/libpq.sgml
M doc/src/sgml/monitoring.sgml
M doc/src/sgml/mvcc.sgml
M doc/src/sgml/parallel.sgml
M doc/src/sgml/perform.sgml
M doc/src/sgml/protocol.sgml
M doc/src/sgml/queries.sgml
M doc/src/sgml/recovery-config.sgml
M doc/src/sgml/ref/create_database.sgml
M doc/src/sgml/ref/create_event_trigger.sgml
M doc/src/sgml/ref/create_function.sgml
M doc/src/sgml/ref/grant.sgml
M doc/src/sgml/ref/initdb.sgml
M doc/src/sgml/ref/pg_dump.sgml
M doc/src/sgml/ref/pg_dumpall.sgml
M doc/src/sgml/ref/pg_restore.sgml
M doc/src/sgml/ref/pg_rewind.sgml
M doc/src/sgml/ref/pgbench.sgml
M doc/src/sgml/ref/pgupgrade.sgml
M doc/src/sgml/ref/postgres-ref.sgml
M doc/src/sgml/ref/prepare.sgml
M doc/src/sgml/ref/psql-ref.sgml
M doc/src/sgml/release-9.6.sgml
M doc/src/sgml/replication-origins.sgml
M doc/src/sgml/runtime.sgml
M doc/src/sgml/sepgsql.sgml
M doc/src/sgml/sources.sgml
M doc/src/sgml/sslinfo.sgml
M doc/src/sgml/wal.sgml
M doc/src/sgml/xfunc.sgml
M doc/src/sgml/xml2.sgml

C comment: remove mention of use of t_hoff WAL structure member

commit   : 160c8a4d382204ca2983aba56cc9e5db7167354e    
  
author   : Bruce Momjian <bruce@momjian.us>    
date     : Mon, 31 Aug 2020 17:51:31 -0400    
  
committer: Bruce Momjian <bruce@momjian.us>    
date     : Mon, 31 Aug 2020 17:51:31 -0400    

Click here for diff

Reported-by: Antonin Houska  
  
Discussion: https://postgr.es/m/21643.1595353537@antos  
  
Backpatch-through: 9.5  

M src/include/access/heapam_xlog.h

pg_upgrade doc: mention saving postgresql.conf.auto files

commit   : cda4397f2bc32976f774bf0ec0b3b7d40a77d64e    
  
author   : Bruce Momjian <bruce@momjian.us>    
date     : Mon, 31 Aug 2020 17:36:22 -0400    
  
committer: Bruce Momjian <bruce@momjian.us>    
date     : Mon, 31 Aug 2020 17:36:22 -0400    

Click here for diff

Also mention files included by postgresql.conf.  
  
Reported-by: Álvaro Herrera  
  
Discussion: https://postgr.es/m/08AD4526-75AB-457B-B2DD-099663F28040@yesql.se  
  
Backpatch-through: 9.5  

M doc/src/sgml/ref/pgupgrade.sgml

docs: in mapping SQL to C data types, timestamp isn't a pointer

commit   : 511d51acb33c780f3be018ace68d3f7fb963ea63    
  
author   : Bruce Momjian <bruce@momjian.us>    
date     : Mon, 31 Aug 2020 17:05:53 -0400    
  
committer: Bruce Momjian <bruce@momjian.us>    
date     : Mon, 31 Aug 2020 17:05:53 -0400    

Click here for diff

It is an int64.  
  
Reported-by: ajulien@shaktiware.fr  
  
Discussion: https://postgr.es/m/159845038271.24995.15682121015698255155@wrigleys.postgresql.org  
  
Backpatch-through: 9.5  

M doc/src/sgml/xfunc.sgml

commit   : e80e7891d35ec94659c3fe8f1d69007d7b05af42    
  
author   : Bruce Momjian <bruce@momjian.us>    
date     : Mon, 31 Aug 2020 16:59:58 -0400    
  
committer: Bruce Momjian <bruce@momjian.us>    
date     : Mon, 31 Aug 2020 16:59:58 -0400    

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There is an file-fdw example that reads the server config file, so cross  
link them.  
  
Reported-by: Oleg Samoilov  
  
Discussion: https://postgr.es/m/159800192078.2886.10431506404995508950@wrigleys.postgresql.org  
  
Backpatch-through: 9.5  

M doc/src/sgml/config.sgml
M doc/src/sgml/file-fdw.sgml

docs: clarify intermediate certificate creation instructions

commit   : 361217659dc80e8f7763eaba047d19391d908f9d    
  
author   : Bruce Momjian <bruce@momjian.us>    
date     : Mon, 31 Aug 2020 16:21:03 -0400    
  
committer: Bruce Momjian <bruce@momjian.us>    
date     : Mon, 31 Aug 2020 16:21:03 -0400    

Click here for diff

Specifically, explain the v3_ca openssl specification.  
  
Discussion: https://postgr.es/m/20200824175653.GA32411@momjian.us  
  
Backpatch-through: 9.5  

M doc/src/sgml/runtime.sgml

docs: replace "stable storage" with "durable" in descriptions

commit   : aa02d352b53329287b22092ed41a9a9ec23b0ef8    
  
author   : Bruce Momjian <bruce@momjian.us>    
date     : Mon, 31 Aug 2020 15:23:18 -0400    
  
committer: Bruce Momjian <bruce@momjian.us>    
date     : Mon, 31 Aug 2020 15:23:18 -0400    

Click here for diff

For PG, "durable storage" has a clear meaning, while "stable storage"  
does not, so use the former.  
  
Discussion: https://postgr.es/m/20200817165222.GA31806@momjian.us  
  
Backpatch-through: 9.5  

M doc/src/sgml/config.sgml

doc: improve description of subscripting of arrays

commit   : dd00de928c3fe59f48510f6d02e5e9b8d72c8ae5    
  
author   : Bruce Momjian <bruce@momjian.us>    
date     : Mon, 31 Aug 2020 13:49:17 -0400    
  
committer: Bruce Momjian <bruce@momjian.us>    
date     : Mon, 31 Aug 2020 13:49:17 -0400    

Click here for diff

It wasn't clear the non-integers are cast to integers for subscripting,  
rather than throwing an error.  
  
Reported-by: sean@materialize.io  
  
Discussion: https://postgr.es/m/159538675800.624.7728794628229799531@wrigleys.postgresql.org  
  
Backpatch-through: 9.5  

M doc/src/sgml/syntax.sgml

docs: improve 'capitals' inheritance example

commit   : 4d93773798d68915b3b7d870bdceae9869b62f03    
  
author   : Bruce Momjian <bruce@momjian.us>    
date     : Mon, 31 Aug 2020 13:43:04 -0400    
  
committer: Bruce Momjian <bruce@momjian.us>    
date     : Mon, 31 Aug 2020 13:43:04 -0400    

Click here for diff

Adds constraints and improves wording.  
  
Reported-by: 2552891@gmail.com  
  
Discussion: https://postgr.es/m/159586122762.680.1361378513036616007@wrigleys.postgresql.org  
  
Backpatch-through: 9.5  

M doc/src/sgml/advanced.sgml

Fix docs bug stating file_fdw requires absolute paths

commit   : fd0f8a6c3a9e30cfd3d1c1ccfb4bb214639b18b4    
  
author   : Magnus Hagander <magnus@hagander.net>    
date     : Mon, 31 Aug 2020 13:03:54 +0200    
  
committer: Magnus Hagander <magnus@hagander.net>    
date     : Mon, 31 Aug 2020 13:03:54 +0200    

Click here for diff

It has always (since the first commit) worked with relative paths, so  
use the same wording as other parts of the documentation.  
  
Author: Bruce Momjian  
Discussion: https://postgr.es/m/CABUevExx-hm=cit+A9LeKBH39srvk8Y2tEZeEAj5mP8YfzNKUg@mail.gmail.com  

M doc/src/sgml/file-fdw.sgml

Mark factorial operator, and postfix operators in general, as deprecated.

commit   : 1ce20826ce80af757658b682c94acb584916e5fe    
  
author   : Tom Lane <tgl@sss.pgh.pa.us>    
date     : Sun, 30 Aug 2020 16:03:19 -0400    
  
committer: Tom Lane <tgl@sss.pgh.pa.us>    
date     : Sun, 30 Aug 2020 16:03:19 -0400    

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Back-patch key parts of 4c5cf5431 and 6ca547cf7 into stable branches.  
I didn't touch pg_description entries here, so it's purely a docs  
change; and I didn't fool with any examples either.  The main point  
is so that anyone who's wondering if factorial() exists in the stable  
branches will be reassured.  
  
Mark Dilger and John Naylor, with some adjustments by me  
  
Discussion: https://postgr.es/m/BE2DF53D-251A-4E26-972F-930E523580E9@enterprisedb.com  

M doc/src/sgml/func.sgml
M doc/src/sgml/ref/create_operator.sgml

Fix code for re-finding scan position in a multicolumn GIN index.

commit   : 0dfec43c829af7e48a159fa5da13f5e48025f985    
  
author   : Tom Lane <tgl@sss.pgh.pa.us>    
date     : Thu, 27 Aug 2020 17:36:13 -0400    
  
committer: Tom Lane <tgl@sss.pgh.pa.us>    
date     : Thu, 27 Aug 2020 17:36:13 -0400    

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collectMatchBitmap() needs to re-find the index tuple it was previously  
looking at, after transiently dropping lock on the index page it's on.  
The tuple should still exist and be at its prior position or somewhere  
to the right of that, since ginvacuum never removes tuples but  
concurrent insertions could add one.  However, there was a thinko in  
that logic, to the effect of expecting any inserted tuples to have the  
same index "attnum" as what we'd been scanning.  Since there's no  
physical separation of tuples with different attnums, it's not terribly  
hard to devise scenarios where this fails, leading to transient "lost  
saved point in index" errors.  (While I've duplicated this with manual  
testing, it seems impossible to make a reproducible test case with our  
available testing technology.)  
  
Fix by just continuing the scan when the attnum doesn't match.  
  
While here, improve the error message used if we do fail, so that it  
matches the wording used in btree for a similar case.  
  
collectMatchBitmap()'s posting-tree code path was previously not  
exercised at all by our regression tests.  While I can't make  
a regression test that exhibits the bug, I can at least improve  
the code coverage here, so do that.  The test case I made for this  
is an extension of one added by 4b754d6c1, so it only works in  
HEAD and v13; didn't seem worth trying hard to back-patch it.  
  
Per bug #16595 from Jesse Kinkead.  This has been broken since  
multicolumn capability was added to GIN (commit 27cb66fdf),  
so back-patch to all supported branches.  
  
Discussion: https://postgr.es/m/16595-633118be8eef9ce2@postgresql.org  

M src/backend/access/gin/ginget.c

docs: client certificates are always sent to the server

commit   : 6efa6aa96276297a937945feee777d7902a1deb2    
  
author   : Bruce Momjian <bruce@momjian.us>    
date     : Tue, 25 Aug 2020 09:53:12 -0400    
  
committer: Bruce Momjian <bruce@momjian.us>    
date     : Tue, 25 Aug 2020 09:53:12 -0400    

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They are not "requested" by the server.  
  
Reported-by: Kyotaro Horiguchi  
  
Discussion: https://postgr.es/m/20200825.155320.986648039251743210.horikyota.ntt@gmail.com  
  
Backpatch-through: 9.5  

M doc/src/sgml/libpq.sgml

Avoid pushing quals down into sub-queries that have grouping sets.

commit   : d3701bc8a25bfcc9904e9b11f0a354b1fc0947bd    
  
author   : Tom Lane <tgl@sss.pgh.pa.us>    
date     : Sat, 22 Aug 2020 14:46:40 -0400    
  
committer: Tom Lane <tgl@sss.pgh.pa.us>    
date     : Sat, 22 Aug 2020 14:46:40 -0400    

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The trouble with doing this is that an apparently-constant subquery  
output column isn't really constant if it is a grouping column that  
appears in only some of the grouping sets.  A qual using such a  
column would be subject to incorrect const-folding after push-down,  
as seen in bug #16585 from Paul Sivash.  
  
To fix, just disable qual pushdown altogether if the sub-query has  
nonempty groupingSets.  While we could imagine far less restrictive  
solutions, there is not much point in working harder right now,  
because subquery_planner() won't move HAVING clauses to WHERE within  
such a subquery.  If the qual stays in HAVING it's not going to be  
a lot more useful than if we'd kept it at the outer level.  
  
Having said that, this restriction could be removed if we used a  
parsetree representation that distinguished such outputs from actual  
constants, which is something I hope to do in future.  Hence, make  
the patch a minimal addition rather than integrating it more tightly  
(e.g. by renumbering the existing items in subquery_is_pushdown_safe's  
comment).  
  
Back-patch to 9.5 where grouping sets were introduced.  
  
Discussion: https://postgr.es/m/16585-9d8c340d23ade8c1@postgresql.org  

M src/backend/optimizer/path/allpaths.c
M src/test/regress/expected/groupingsets.out
M src/test/regress/sql/groupingsets.sql

docs: improve description of how to handle multiple databases

commit   : 190fb57c4423f2ef64358f090a828e5fc29a1566    
  
author   : Bruce Momjian <bruce@momjian.us>    
date     : Fri, 21 Aug 2020 20:23:09 -0400    
  
committer: Bruce Momjian <bruce@momjian.us>    
date     : Fri, 21 Aug 2020 20:23:09 -0400    

Click here for diff

This is a redesign of the intro to the managing databases chapter.  
  
Discussion: https://postgr.es/m/159586122762.680.1361378513036616007@wrigleys.postgresql.org  
  
Author: David G. Johnston  
  
Backpatch-through: 9.5  

M doc/src/sgml/manage-ag.sgml

Fix handling of CREATE TABLE LIKE with inheritance.

commit   : 37681d7e942e31256efdd9b562a750f1742ac111    
  
author   : Tom Lane <tgl@sss.pgh.pa.us>    
date     : Fri, 21 Aug 2020 15:00:43 -0400    
  
committer: Tom Lane <tgl@sss.pgh.pa.us>    
date     : Fri, 21 Aug 2020 15:00:43 -0400    

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If a CREATE TABLE command uses both LIKE and traditional inheritance,  
Vars in CHECK constraints and expression indexes that are absorbed  
from a LIKE parent table tended to get mis-numbered, resulting in  
wrong answers and/or bizarre error messages (though probably not any  
actual crashes, thanks to validation occurring in the executor).  
  
In v12 and up, the same could happen to Vars in GENERATED expressions,  
even in cases with no LIKE clause but multiple traditional-inheritance  
parents.  
  
The cause of the problem for LIKE is that parse_utilcmd.c supposed  
it could renumber such Vars correctly during transformCreateStmt(),  
which it cannot since we have not yet accounted for columns added via  
inheritance.  Fix that by postponing processing of LIKE INCLUDING  
CONSTRAINTS, DEFAULTS, GENERATED, INDEXES till after we've performed  
DefineRelation().  
  
The error with GENERATED and multiple inheritance is a simple oversight  
in MergeAttributes(); it knows it has to renumber Vars in inherited  
CHECK constraints, but forgot to apply the same processing to inherited  
GENERATED expressions (a/k/a defaults).  
  
Per bug #16272 from Tom Gottfried.  The non-GENERATED variants of the  
issue are ancient, presumably dating right back to the addition of  
CREATE TABLE LIKE; hence back-patch to all supported branches.  
  
Discussion: https://postgr.es/m/16272-6e32da020e9a9381@postgresql.org  

M src/backend/parser/parse_utilcmd.c
M src/backend/tcop/utility.c
M src/include/parser/parse_utilcmd.h
M src/test/regress/expected/create_table_like.out
M src/test/regress/sql/create_table_like.sql

Disable autovacuum for BRIN test table

commit   : d4d21490376e3dc863484b97c60cce08096218ce    
  
author   : Alvaro Herrera <alvherre@alvh.no-ip.org>    
date     : Mon, 17 Aug 2020 16:20:05 -0400    
  
committer: Alvaro Herrera <alvherre@alvh.no-ip.org>    
date     : Mon, 17 Aug 2020 16:20:05 -0400    

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This should improve stability in the tests.  
  
Per buildfarm member hyrax (CLOBBER_CACHE_ALWAYS) via Tom Lane.  
  
Discussion: https://postgr.es/m/871534.1597503261@sss.pgh.pa.us  

M src/test/regress/expected/brin.out
M src/test/regress/sql/brin.sql

Doc: fix description of UNION/CASE/etc type unification.

commit   : 722564cf0d7cbcd56b05d8945c360f6e56ba715d    
  
author   : Tom Lane <tgl@sss.pgh.pa.us>    
date     : Mon, 17 Aug 2020 15:40:07 -0400    
  
committer: Tom Lane <tgl@sss.pgh.pa.us>    
date     : Mon, 17 Aug 2020 15:40:07 -0400    

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The description of what select_common_type() does was not terribly  
accurate.  Improve it.  
  
David Johnston and Tom Lane  
  
Discussion: https://postgr.es/m/1019930.1597613200@sss.pgh.pa.us  

M doc/src/sgml/typeconv.sgml

doc: Fix description about bgwriter and checkpoint in HA section

commit   : 5b39f772e2c1670eea2cfde0cc8b08183b010d0e    
  
author   : Michael Paquier <michael@paquier.xyz>    
date     : Mon, 17 Aug 2020 10:24:42 +0900    
  
committer: Michael Paquier <michael@paquier.xyz>    
date     : Mon, 17 Aug 2020 10:24:42 +0900    

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Since 806a2ae, the work of the bgwriter is split the checkpointer, but a  
portion of the documentation did not get the message.  
  
Author: Masahiko Sawada  
Discussion: https://postgr.es/m/CA+fd4k6jXxjAtjMVC=wG3=QGpauZBtcgN3Jhw+oV7zXGKVLKzQ@mail.gmail.com  
Backpatch-through: 9.5  

M doc/src/sgml/high-availability.sgml

Move new LOCKTAG_DATABASE_FROZEN_IDS to end of enum LockTagType.

commit   : 85aa22cb120d0ee91d41dfa27d307a95f01df89f    
  
author   : Noah Misch <noah@leadboat.com>    
date     : Sat, 15 Aug 2020 16:15:59 -0700    
  
committer: Noah Misch <noah@leadboat.com>    
date     : Sat, 15 Aug 2020 16:15:59 -0700    

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Several PGXN modules reference LockTagType values; renumbering would  
force a recompile of those modules.  Oversight in back-patch of today's  
commit 566372b3d6435639e4cc4476d79b8505a0297c87.  Back-patch to released  
branches, v12 through 9.5.  
  
Reported by Tom Lane.  
  
Discussion: https://postgr.es/m/921383.1597523945@sss.pgh.pa.us  

M src/backend/utils/adt/lockfuncs.c
M src/include/storage/lock.h

Prevent concurrent SimpleLruTruncate() for any given SLRU.

commit   : 5ae01df6f6ef590fd73299050c7112f69c03f3de    
  
author   : Noah Misch <noah@leadboat.com>    
date     : Sat, 15 Aug 2020 10:15:53 -0700    
  
committer: Noah Misch <noah@leadboat.com>    
date     : Sat, 15 Aug 2020 10:15:53 -0700    

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The SimpleLruTruncate() header comment states the new coding rule.  To  
achieve this, add locktype "frozenid" and two LWLocks.  This closes a  
rare opportunity for data loss, which manifested as "apparent  
wraparound" or "could not access status of transaction" errors.  Data  
loss is more likely in pg_multixact, due to released branches' thin  
margin between multiStopLimit and multiWrapLimit.  If a user's physical  
replication primary logged ":  apparent wraparound" messages, the user  
should rebuild standbys of that primary regardless of symptoms.  At less  
risk is a cluster having emitted "not accepting commands" errors or  
"must be vacuumed" warnings at some point.  One can test a cluster for  
this data loss by running VACUUM FREEZE in every database.  Back-patch  
to 9.5 (all supported versions).  
  
Discussion: https://postgr.es/m/20190218073103.GA1434723@rfd.leadboat.com  

M doc/src/sgml/catalogs.sgml
M doc/src/sgml/monitoring.sgml
M src/backend/access/transam/slru.c
M src/backend/access/transam/subtrans.c
M src/backend/commands/async.c
M src/backend/commands/vacuum.c
M src/backend/storage/lmgr/lmgr.c
M src/backend/storage/lmgr/lwlocknames.txt
M src/backend/utils/adt/lockfuncs.c
M src/include/storage/lmgr.h
M src/include/storage/lock.h

Be more careful about the shape of hashable subplan clauses.

commit   : 7241edc4fa8cda23d04bfe3cd139ed27904eac04    
  
author   : Tom Lane <tgl@sss.pgh.pa.us>    
date     : Fri, 14 Aug 2020 22:14:03 -0400    
  
committer: Tom Lane <tgl@sss.pgh.pa.us>    
date     : Fri, 14 Aug 2020 22:14:03 -0400    

Click here for diff

nodeSubplan.c expects that the testexpr for a hashable ANY SubPlan  
has the form of one or more OpExprs whose LHS is an expression of the  
outer query's, while the RHS is an expression over Params representing  
output columns of the subquery.  However, the planner only went as far  
as verifying that the clauses were all binary OpExprs.  This works  
99.99% of the time, because the clauses have the right shape when  
emitted by the parser --- but it's possible for function inlining to  
break that, as reported by PegoraroF10.  To fix, teach the planner  
to check that the LHS and RHS contain the right things, or more  
accurately don't contain the wrong things.  Given that this has been  
broken for years without anyone noticing, it seems sufficient to just  
give up hashing when it happens, rather than go to the trouble of  
commuting the clauses back again (which wouldn't necessarily work  
anyway).  
  
While poking at that, I also noticed that nodeSubplan.c had a baked-in  
assumption that the number of hash clauses is identical to the number  
of subquery output columns.  Again, that's fine as far as parser output  
goes, but it's not hard to break it via function inlining.  There seems  
little reason for that assumption though --- AFAICS, the only thing  
it's buying us is not having to store the number of hash clauses  
explicitly.  Adding code to the planner to reject such cases would take  
more code than getting nodeSubplan.c to cope, so I fixed it that way.  
  
This has been broken for as long as we've had hashable SubPlans,  
so back-patch to all supported branches.  
  
Discussion: https://postgr.es/m/1549209182255-0.post@n3.nabble.com  

M src/backend/executor/nodeSubplan.c
M src/backend/optimizer/plan/subselect.c
M src/backend/optimizer/util/clauses.c
M src/include/nodes/execnodes.h
M src/include/optimizer/clauses.h
M src/test/regress/expected/subselect.out
M src/test/regress/sql/subselect.sql

Fix postmaster's behavior during smart shutdown.

commit   : b4d8be9f6dc892bd69cf99b587a7d6f925d43ca3    
  
author   : Tom Lane <tgl@sss.pgh.pa.us>    
date     : Fri, 14 Aug 2020 13:26:57 -0400    
  
committer: Tom Lane <tgl@sss.pgh.pa.us>    
date     : Fri, 14 Aug 2020 13:26:57 -0400    

Click here for diff

Up to now, upon receipt of a SIGTERM ("smart shutdown" command), the  
postmaster has immediately killed all "optional" background processes,  
and subsequently refused to launch new ones while it's waiting for  
foreground client processes to exit.  No doubt this seemed like an OK  
policy at some point; but it's a pretty bad one now, because it makes  
for a seriously degraded environment for the remaining clients:  
  
* Parallel queries are killed, and new ones fail to launch. (And our  
parallel-query infrastructure utterly fails to deal with the case  
in a reasonable way --- it just hangs waiting for workers that are  
not going to arrive.  There is more work needed in that area IMO.)  
  
* Autovacuum ceases to function.  We can tolerate that for awhile,  
but if bulk-update queries continue to run in the surviving client  
sessions, there's eventually going to be a mess.  In the worst case  
the system could reach a forced shutdown to prevent XID wraparound.  
  
* The bgwriter and walwriter are also stopped immediately, likely  
resulting in performance degradation.  
  
Hence, let's rearrange things so that the only immediate change in  
behavior is refusing to let in new normal connections.  Once the last  
normal connection is gone, shut everything down as though we'd received  
a "fast" shutdown.  To implement this, remove the PM_WAIT_BACKUP and  
PM_WAIT_READONLY states, instead staying in PM_RUN or PM_HOT_STANDBY  
while normal connections remain.  A subsidiary state variable tracks  
whether or not we're letting in new connections in those states.  
  
This also allows having just one copy of the logic for killing child  
processes in smart and fast shutdown modes.  I moved that logic into  
PostmasterStateMachine() by inventing a new state PM_STOP_BACKENDS.  
  
Back-patch to 9.6 where parallel query was added.  In principle  
this'd be a good idea in 9.5 as well, but the risk/reward ratio  
is not as good there, since lack of autovacuum is not a problem  
during typical uses of smart shutdown.  
  
Per report from Bharath Rupireddy.  
  
Patch by me, reviewed by Thomas Munro  
  
Discussion: https://postgr.es/m/CALj2ACXAZ5vKxT9P7P89D87i3MDO9bfS+_bjMHgnWJs8uwUOOw@mail.gmail.com  

M doc/src/sgml/ref/pg_ctl-ref.sgml
M src/backend/postmaster/postmaster.c
M src/backend/utils/init/postinit.c
M src/include/libpq/libpq-be.h

Handle new HOT chains in index-build table scans

commit   : e5902117dd83a330caf68ec2a479c4410cef5518    
  
author   : Alvaro Herrera <alvherre@alvh.no-ip.org>    
date     : Thu, 13 Aug 2020 17:33:49 -0400    
  
committer: Alvaro Herrera <alvherre@alvh.no-ip.org>    
date     : Thu, 13 Aug 2020 17:33:49 -0400    

Click here for diff

When a table is scanned by heapam_index_build_range_scan (née  
IndexBuildHeapScan) and the table lock being held allows concurrent data  
changes, it is possible for new HOT chains to sprout in a page that were  
unknown when the scan of a page happened.  This leads to an error such  
as  
  ERROR:  failed to find parent tuple for heap-only tuple at (X,Y) in table "tbl"  
because the root tuple was not present when we first obtained the list  
of the page's root tuples.  This can be fixed by re-obtaining the list  
of root tuples, if we see that a heap-only tuple appears to point to a  
non-existing root.  
  
This was reported by Anastasia as occurring for BRIN summarization  
(which exists since 9.5), but I think it could theoretically also happen  
with CREATE INDEX CONCURRENTLY (much older) or REINDEX CONCURRENTLY  
(very recent).  It seems a happy coincidence that BRIN forces us to  
backpatch this all the way to 9.5.  
  
Reported-by: Anastasia Lubennikova <a.lubennikova@postgrespro.ru>  
Diagnosed-by: Anastasia Lubennikova <a.lubennikova@postgrespro.ru>  
Co-authored-by: Anastasia Lubennikova <a.lubennikova@postgrespro.ru>  
Co-authored-by: Álvaro Herrera <alvherre@alvh.no-ip.org>  
Discussion: https://postgr.es/m/602d8487-f0b2-5486-0088-0f372b2549fa@postgrespro.ru  
Backpatch: 9.5 - master  

M src/backend/access/heap/pruneheap.c
M src/backend/catalog/index.c

BRIN: Handle concurrent desummarization properly

commit   : 7a3c261fbbb427ffa2ee9223728e811556284a6e    
  
author   : Alvaro Herrera <alvherre@alvh.no-ip.org>    
date     : Wed, 12 Aug 2020 15:33:36 -0400    
  
committer: Alvaro Herrera <alvherre@alvh.no-ip.org>    
date     : Wed, 12 Aug 2020 15:33:36 -0400    

Click here for diff

If a page range is desummarized at just the right time concurrently with  
an index walk, BRIN would raise an error indicating index corruption.  
This is scary and unhelpful; silently returning that the page range is  
not summarized is sufficient reaction.  
  
This bug was introduced by commit 975ad4e602ff as additional protection  
against a bug whose actual fix was elsewhere.  Backpatch equally.  
  
Reported-By: Anastasia Lubennikova <a.lubennikova@postgrespro.ru>  
Diagnosed-By: Alexander Lakhin <exclusion@gmail.com>  
Discussion: https://postgr.es/m/2588667e-d07d-7e10-74e2-7e1e46194491@postgrespro.ru  
Backpatch: 9.5 - master  

M src/backend/access/brin/brin_revmap.c