"operator" is a reserved word in C++, so per project conventions,
don't use it as an identifier in header files.

My oversight in commit a8081860.

Older gcc versions don't like duplicate typedefs, so get rid of
that in favor of doing it like we do it elsewhere, ie just use
a "struct" declaration when trying to avoid importing a whole
header file.

Also, there seems no reason to include stringinfo.h here at all,
so get rid of that addition too.

Discussion: https://postgr.es/m/27239.1587415696@sss.pgh.pa.us

Previously in the "Standby Server Operation" section, pg_ctl promote and
protmote_trigger_file were documented as a method to trigger standby
promotion, but pg_promote() function not.

This commit also adds parentheses into <function>pg_promote</function>
in some docs to make it clearer that a function is being referred to.

Author: Masahiro Ikeda
Reviewed-by: Michael Paquier, Laurenz Albe, Tom Lane, Fujii Masao
Discussion: https://postgr.es/m/de0068417a9f4046bac693cbcc00bdc9@oss.nttdata.com

Reported-by: Jürgen Purtz

Discussion: https://postgr.es/m/709d7809-d7f4-8175-47f3-4d131341bba8@purtz.de

Author: Jürgen Purtz

Backpatch-through: 9.5

Also some mop-up in section 9.9.

basebackup.c is already a pretty big and complicated file, so it
makes more sense to keep the backup manifest support routines
in a separate file, for clarity and ease of maintenance.

Discussion: http://postgr.es/m/CA+TgmoavRak5OdP76P8eJExDYhPEKWjMb0sxW7dF01dWFgE=uA@mail.gmail.com

... as added in the prior commit.

(We'd like to have tab-completion for the other object types too, but
they don't have sub-command completion yet.)

Author: Ibrar Ahmed <ibrar.ahmad@gmail.com>
Reviewed-by: Álvaro Herrera <alvherre@alvh.no-ip.org>
Discussion: https://postgr.es/m/CALtqXTcogrFEVP9uou5vFtnGsn+vHZUu9+9a0inarfYVOHScYQ@mail.gmail.com

Commit f2fcad27 (9.6 era) added the ability to mark objects as
dependent an extension, but forgot to add a way for such dependencies to
be removed.  This commit fixes that oversight.

Strictly speaking this should be backpatched to 9.6, but due to lack of
demand we're not doing so at this time.

Discussion: https://postgr.es/m/20200217225333.GA30974@alvherre.pgsqlReviewed-by: ahsan hadi <ahsan.hadi@gmail.com>
Reviewed-by: Ibrar Ahmed <ibrar.ahmad@gmail.com>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>

Along the way, update the older examples for bytea to use "hex"
output format.  That lets us get rid of the lame disclaimer about
how the examples assume bytea_output = escape, which was only half
true anyway because none of the more-recently-added examples had
paid any attention to that.

The views pg_stat_progress_* had not gotten the memo that
pg_read_all_stats is supposed to be able to read all statistics. Also
make a pass over all text-returning pg_stat_xyz functions that could
return "insufficient privilege" and make sure they also respect
pg_read_all_status.

Reported-by: Andrey M. Borodin
Reviewed-by: Andrey M. Borodin, Kyotaro Horiguchi
Discussion: https://postgr.es/m/13145F2F-8458-4977-9D2D-7B2E862E5722@yandex-team.ru

Notably, this replaces the previous handwaving about these functions'
behavior with "character"-type inputs with some actual facts.

I took the opportunity to do some copy-editing in this area as well,
and to add some new material such as a note about BETWEEN's syntactical
peculiarities.

Of note is that quite a few of the examples of transcendental functions
needed to be updated, because the displayed output no longer matched
what you get on a modern server.  I believe some of these cases are
side-effects of the new Ryu algorithm in float8out.  Others appear to be
because the examples predate the addition of type numeric, and were
expecting that float8 calculations would be done although the given
syntax would actually lead to calling the numeric function nowadays.

The normalization-check target needs to be run last, after moving the
newly generated files into place.  Also, we need an additional
dependency so that unicode_norm.o is rebuilt first.  Otherwise,
norm_test will still test the old files but against the new expected
results, which will probably fail.

Jonathan Katz felt that slightly different indentation settings made
for a better-looking result, so sync stylesheet-fo.xsl (for PDF) and
stylesheet.css (for non-website-style HTML) with those choices.

Discussion: https://postgr.es/m/31464.1587156281@sss.pgh.pa.us

We have repeatedly seen the buildfarm reach the Assert(false) in
SyncRepGetSyncStandbysPriority.  This apparently is due to failing to
consider the possibility that the sync_standby_priority values in
shared memory might be inconsistent; but they will be whenever only
some of the walsenders have updated their values after a change in
the synchronous_standby_names setting.  That function is vastly too
complex for what it does, anyway, so rewriting it seems better than
trying to apply a band-aid fix.

Furthermore, the API of SyncRepGetSyncStandbys is broken by design:
it returns a list of WalSnd array indexes, but there is nothing
guaranteeing that the contents of the WalSnd array remain stable.
Thus, if some walsender exits and then a new walsender process
takes over that WalSnd array slot, a caller might make use of
WAL position data that it should not, potentially leading to
incorrect decisions about whether to release transactions that
are waiting for synchronous commit.

To fix, replace SyncRepGetSyncStandbys with a new function
SyncRepGetCandidateStandbys that copies all the required data
from shared memory while holding the relevant mutexes.  If the
associated walsender process then exits, this data is still safe to
make release decisions with, since we know that that much WAL *was*
sent to a valid standby server.  This incidentally means that we no
longer need to treat sync_standby_priority as protected by the
SyncRepLock rather than the per-walsender mutex.

SyncRepGetSyncStandbys is no longer used by the core code, so remove
it entirely in HEAD.  However, it seems possible that external code is
relying on that function, so do not remove it from the back branches.
Instead, just remove the known-incorrect Assert.  When the bug occurs,
the function will return a too-short list, which callers should treat
as meaning there are not enough sync standbys, which seems like a
reasonably safe fallback until the inconsistent state is resolved.
Moreover it's bug-compatible with what has been happening in non-assert
builds.  We cannot do anything about the walsender-replacement race
condition without an API/ABI break.

The bogus assertion exists back to 9.6, but 9.6 is sufficiently
different from the later branches that the patch doesn't apply at all.
I chose to just remove the bogus assertion in 9.6, feeling that the
probability of a bad outcome from the walsender-replacement race
condition is too low to justify rewriting the whole patch for 9.6.

Discussion: https://postgr.es/m/21519.1585272409@sss.pgh.pa.us

In some corner cases, this could also lead to corrupted values being
included in the tuple.

Users who are concerned that they are affected by this should first
upgrade and then perform a base backup of their database and restore onto
an off-line server. They should then query each table with generated
columns to ensure there are no rows where the generated expression does
not match a newly calculated version of the GENERATED ALWAYS expression.
If no crashes occur and no rows are returned then you're not affected.

Fixes bug #16369.

Reported-by: Cameron Ezell
Discussion: https://postgr.es/m/16369-5845a6f1bef59884@postgresql.org
Backpatch-through: 12 (where GENERATED ALWAYS columns were added.)

The table layout ideas proposed in commit e894c618 were not as widely
popular as I'd hoped.  After discussion, we've settled on a layout
that's effectively a single-column table with cell contents much like a
<varlistentry> description of the function or operator; though we're not
actually using <varlistentry>, because it'd add way too much vertical
space.  Instead the effect is accomplished using line-break processing
instructions to separate the description and example(s), plus CSS or FO
customizations to produce indentation of all but the first line in each
cell.  While technically this is a bit grotty, it does have the
advantage that we won't need to write nearly as much boilerplate markup.

This patch updates tables 9.30, 9.31, and 9.33 (which were touched by
the previous patch) to the revised style, and additionally converts
table 9.10.  A lot of work still remains to do, but hopefully it won't
be too controversial.

Thanks to Andrew Dunstan, Pierre Giraud, Robert Haas, Alvaro Herrera,
David Johnston, Jonathan Katz, Isaac Morland for valuable ideas.

Discussion: https://postgr.es/m/8691.1586798003@sss.pgh.pa.us

This reverts commit 9e24109f.

This caused build errors when building without openssl, and it's
simplest just to revert it.

This should have been protected by #ifdef USE_OPENSSL in commit
896fcdb2.

Per the real complaint this time from Daniel Gustafsson.

Apparently in some language versions of Visual Studio nmake outputs some
material after the version number and before the end of the line. This
has been seen in Chinese versions. Therefore, we no longer demand that
the version string comes at the end of a line.

Per complaint from Cuiping Lin.

Backpatch to all live branches.

In commit 4dc63552 I neglected to put #ifdef USE_OPENSSL around the
declarations of the new items. This is remedied here.

Per complaint from Daniel Gustafsson.

recordExtObjInitPriv and removeExtObjInitPriv were sloppy about
calling ReleaseSysCache.  The cases cannot occur given current usage
in ALTER EXTENSION ADD/DROP, since we wouldn't get here for these
relkinds; but it seems wise to clean up better.

In passing, extend test logic in test_pg_dump to exercise the
dropped-column code paths here.

Since the case is unreachable at present, there seems no great
need to back-patch; hence fix HEAD only.

Kyotaro Horiguchi, with test case and comment adjustments by me

Discussion: https://postgr.es/m/20200417.151831.1153577605111650154.horikyota.ntt@gmail.com

Author: Fujii Masao
Reviewed-by: Robert Haas
Discussion: https://postgr.es/m/951743d0-fd7e-8e2b-d489-1368a58b7304@oss.nttdata.com

The result of the query used to retrieve the WAL segment size from the
backend was not getting freed in two code paths.  Both pg_basebackup and
pg_receivewal exit immediately if a failure happened on this query, so
this was not an actual problem, but it could be an issue if this code
gets used for other tools in different ways, be they future tools in
this code tree or external, existing, ones.

Oversight in commit fc49e24f, so backpatch down to 11.

Author: Jie Zhang
Discussion: https://postgr.es/m/970ad9508461469b9450b64027842331@G08CNEXMBPEKD06.g08.fujitsu.local
Backpatch-through: 11

It was previously thought that remove_useless_groupby_columns() needed to
keep track of which constraints the generated plan depended upon, however,
this is unnecessary. The confusion likely arose regarding this because of
check_functional_grouping(), which does need to track the dependency to
ensure VIEWs with columns which are functionally dependant on the GROUP BY
remain so. For remove_useless_groupby_columns(), cached plans will just
become invalidated when the primary key's underlying index is removed
through the normal relcache invalidation code.

Here we just remove the unneeded code which records the dependency and
updates the comments. The previous comments claimed that we could not use
UNIQUE constraints for the same optimization due to lack of a
pg_constraint record for NOT NULL constraints (which are required because
NULLs can be duplicated in a unique index). Since we don't actually need a
pg_constraint record to handle the invalidation, it looks like we could
add code to do this in the future. But not today.

We're not really fixing any bug in the code here, this fix is just to set
the record straight on UNIQUE constraints. This code was added back in
9.6, but due to lack of any bug, we'll not be backpatching this.

Reviewed-by: Tom Lane
Discussion: https://postgr.es/m/CAApHDvrdYa=VhOoMe4ZZjZ-G4ALnD-xuAeUNCRTL+PYMVN8OnQ@mail.gmail.com

fixup_whole_row_references() did the wrong thing with a dropped column,
resulting in a commit-time warning about a cache reference leak.

I (tgl) added a test case exercising this, but back-patched the test
only as far as v10; the patch didn't apply cleanly to 9.6 and it
didn't seem worth the trouble to adapt it.  The bug is pretty old
though, so apply the code change all the way back.

Michael Luo, with cosmetic improvements by me

Discussion: https://postgr.es/m/BYAPR08MB5606D1453D7F50E2AF4D2FD29AD80@BYAPR08MB5606.namprd08.prod.outlook.com

Earlier we were inconsistent in allowing the usage of parallel and
full options.  Change it such that we disallow them only when they are
combined in a way that we don't support.

In passing, improve the comments in some of the existing tests of parallel
vacuum.

Reported-by: Tushar Ahuja
Author: Justin Pryzby, Amit Kapila
Reviewed-by: Sawada Masahiko, Michael Paquier, Mahendra Singh Thalor and
Amit Kapila
Discussion: https://postgr.es/m/58c8d171-e665-6fa3-a9d3-d9423b694dae%40enterprisedb.com

Since 0d8c9c12, pg_basebackup would generate an error if connected to a
backend version older than 12 where backup manifests are not supported.
Avoiding this error is possible by using the --no-manifest option.

This error handling could be confusing for some users, where patching a
backup script that interacts with multiple backend versions would cause
the addition of --no-manifest to potentially not generate a backup
manifest even for Postgres 13 and newer versions.  As we want to
encourage the use of backup manifests as much as possible, this commit
silently disables manifests where not supported, instead of generating
an error.

While on it, rework a bit the code to make it more consistent with the
surroundings when generating the BASE_BACKUP command.

Per discussion with Andres Freund, Stephen Frost, Robert Haas, Álvaro
Herrera, Kyotaro Horiguchi, Tom Lane, David Steele, and me.

Author: Michael Paquier
Discussion: https://postgr.es/m/20200410080910.GZ1606@paquier.xyz

Spotted during post-commit review of the nbtree deduplication commit
(commit 0d861bbb).

A query used to read default ACL information from the catalogs did not
free a set of PQExpBuffer.

Oversight in commit e2090d9d, so backpatch down to 9.6.

Author: Jie Zhang
Reviewed-by: Sawada Masahiko
Discussion: https://postgr.es/m/05bcbc5857f948efa0b451b85a48ae10@G08CNEXMBPEKD06.g08.fujitsu.local
Backpatch-through: 9.6

This commit prevents pg_basebackup from receiving backup_manifest file
when --no-manifest is specified. Previously, when pg_basebackup was
writing a tarfile to stdout, it tried to receive backup_manifest file even
when --no-manifest was specified, and reported an error.

Also remove unused -m option from pg_basebackup.

Also fix typo in BASE_BACKUP command documentation.

Author: Fujii Masao
Reviewed-by: Michael Paquier, Robert Haas
Discussion: https://postgr.es/m/01e3ed3a-8729-5aaa-ca84-e60e3ca59db8@oss.nttdata.com

A comment from the Berkeley days incorrectly claimed that the page
management code cares about the contents of the hole in the center of
the page (at least in the case of the left half of an nbtree page
split).  Commit 8fa30f90 added an addendum that stated that the
original comment was "probably obsolete".  It's definitely obsolete,
though, so remove the original comment plus the addendum.

Commit 913bbd88 overlooked that the result of coerce_to_target_type
might need collation fixups.  Per report from Andreas Joseph Krogh.

Discussion: https://postgr.es/m/VisenaEmail.72.37d08ec2b8cb8fb5.17179940cd3@tc7-visena

The consensus of the project appears to be that this provides little
benefit and is simply an annoyance.

Discussion: https://postgr.es/m/27481.1586618092@sss.pgh.pa.us

Back in commits 1df92eea, f884a968, and 592123ef I used some
hackish code to set the script search path, unaware despite decades of
perl that there was a completely standard way to do this. This patch
changes those cases to use the standard perl FindBin package.

Patch by me, at the request of Andres Freund. Reviewed by
Justin Pryzby, Erik Rijkers, Álvaro Herrera, and Andrew
Dunstan.

Discussion: http://postgr.es/m/20200327203225.hcm6ag4grwsiruea@alap3.anarazel.de

Nest the "update metapage as part of insert into root-like page" branch
inside the broader "insert into internal page" branch.  This improves
readability.

This fixes some comments and documentation new as of Postgres 13, and is
a follow-up of the work done in dd0f37ec.

Author: Justin Pryzby
Discussion: https://postgr.es/m/20200408165653.GF2228@telsasoft.com

Clearly it's not okay for nbtree to split a page that is the only page
on its level, and then find that it has to split the parent one level up
in turn.  There is simply no code to handle the split_only_page case in
the _bt_insertonpg() "newitem won't fit" branch (only the "newitem fits"
branch handles split_only_page).  Add a defensive assertion that will
fail if a split_only_page call to _bt_insertonpg() somehow ends up
splitting the target/parent page.

I (pgeoghegan) believe that we don't need split_only_page handling for
the "newitem won't fit" branch because anybody calling _bt_insertonpg()
like this would have to hold a lock on the same one and only child page.