Stop naming special area/opaque pointer variables 'lpageop' in contexts
where it doesn't make sense.  This is a holdover from a time when logic
that performs tasks that are now spread across _bt_insertonpg(),
_bt_findinsertloc(), and _bt_split() was more centralized.  'lpageop'
denotes "left page", which doesn't make sense outside of contexts in
which there isn't also a right page.

Also acquire page flag variables up front within _bt_insertonpg().  This
makes it closer to _bt_split() following refactoring commit bc3087b6.
This allows the page split and retail insert paths to both make use of
the same variables.

In streaming mode, the transaction can be decoded in multiple streams and
those streams can be interleaved with streams of other transactions. So,
we can't remember the transaction's write status in the logical decoding
context because that might get changed due to some other transactions and
lead to wrong answers for 'skip-empty-xacts' option. We decided to keep
each transaction's write status in the ReorderBufferTxn to avoid
interleaved streams changing the status of some unrelated transactions.

Diagnosed-by: Amit Kapila
Author: Dilip Kumar
Reviewed-by: Amit Kapila
Discussion: https://postgr.es/m/CAA4eK1LR7=XNM_TLmpZMFuV8ZQpoxkem--NZJYf8YXmesbvwLA@mail.gmail.com

Otherwise, if FDDEBUG is enabled, the debugging output fails because
it tries to read the fileName, which isn't set up yet (and should in
fact always be NULL).

AFAICT, this has been wrong since Berkeley.  Before 96bf88d5,
it would accidentally fail to crash on platforms where snprintf()
is forgiving about being passed a NULL pointer for %s; but the
file name intended to be included in the debug output wouldn't
ever have shown up.

Report and fix by Greg Nancarrow.  Although this is only visibly
broken in custom-made builds, it still seems worth back-patching
to all supported branches, as the FDDEBUG code is pretty useless
as it stands.

Discussion: https://postgr.es/m/CAJcOf-cUDgm9qYtC_B6XrC6MktMPNRby2p61EtSGZKnfotMArw@mail.gmail.com

With more flags associated to a PGPROC entry that are not related to
vacuum (currently existing or planned), the name "statusFlags" describes
its purpose better.

(The same is done to the mirroring PROC_HDR->vacuumFlags.)

No functional changes in this commit.

This was suggested first by Hari Babu Kommi in [1] and then by Michael
Paquier at [2].

[1] https://postgr.es/m/CAJrrPGcsDC-oy1AhqH0JkXYa0Z2AgbuXzHPpByLoBGMxfOZMEQ@mail.gmail.com
[2] https://postgr.es/m/20200820060929.GB3730@paquier.xyz

Author: Dmitry Dolgov <9erthalion6@gmail.com>
Reviewed-by: Álvaro Herrera <alvherre@alvh.no-ip.org>
Discussion: https://postgr.es/m/20201116182446.qcg3o6szo2zookyr@localhost

Since this function is used as a CHECK constraint condition,
returning NULL is tantamount to returning TRUE, which would have the
effect of letting in a row that doesn't satisfy the hash condition.
Admittedly, the cases for which this is done should be unreachable
in practice, but that doesn't make it any less a bad idea.  It also
seems like a dartboard was used to decide which error cases should
throw errors as opposed to returning NULL.

For the checks for NULL input values, I just switched it to returning
false.  There's some argument that an error would be better; but the
case really should be can't-happen in a generated hash constraint,
so it's likely not worth more code for.

For the parent-relation-open-failure case, it seems like we might
as well let relation_open throw an error, instead of having an
impossible-to-diagnose constraint failure.

Back-patch to v11 where this code came in.

Discussion: https://postgr.es/m/24067.1605134819@sss.pgh.pa.us

This was evidently missed in commit 6337865f, which generally did
s/TRUE/true/ everywhere.  It escaped notice up to now because ICU
versions before ICU 68 provided definitions of "TRUE" and "FALSE"
regardless.  With ICU 68, it fails to compile.

Per report from Condor.  Back-patch to v11 where 6337865f came in.
(I've not tested v10, where this call originated, but I imagine
it's fine since we defined TRUE in c.h back then.)

Discussion: https://postgr.es/m/7a6f3336165bfe3ca66abcda7966f9d0@stz-bg.com

This clarifies exactly what the bgwriter does, which should help with
tuning.

Reported-by: Chris Wilson

Discussion: https://postgr.es/m/160399562040.7809.7335281028960123489@wrigleys.postgresql.org

Backpatch-through: 9.5

Followup to patch 152ed047.

Reported-by: Alvaro Herrera

Discussion: https://postgr.es/m/20201112202900.GA28098@alvherre.pgsql

Backpatch-through: 9.5

These were dead code.

Discussion: https://www.postgresql.org/message-id/flat/20201027032511.GF9241@telsasoft.com

This is a followup commit on 33702079.

Reported-by: Justin Pryzby

Discussion: https://postgr.es/m/20201112211143.GL30691@telsasoft.com

Backpatch-through: 9.5

Introduced in 90fdc259866e; backpatch to 12.

Author: Erik Rijkers <er@xs4all.nl>
Discussion: https://postgr.es/m/e92b3fba98a0c0f7afc0a2a37e765954@xs4all.nl

Change lower case /* empty */ to /* EMPTY */ for consistency with the
majority.

Discussion: https://www.postgresql.org/message-id/flat/e9eed669-e32d-6919-fed4-acc0daea857b%40enterprisedb.com

This removes the code that was there for handling the operators
removed by 2f70fdb0.

Discussion: https://www.postgresql.org/message-id/flat/20201027032511.GF9241@telsasoft.com

This commit changes the startup process in the standby server so that
it handles the interrupt signals after waiting for wal_retrieve_retry_interval
on the latch and resetting it, before entering another wait on the latch.
This change causes the standby server to promptly handle interrupt signals.

Otherwise, previously, there was the case where the standby needs to
wait extra five seconds to shutdown when the shutdown request arrived
while the startup process was waiting for wal_retrieve_retry_interval
on the latch.

Author: Fujii Masao, but implementation idea is from Soumyadeep Chakraborty
Reviewed-by: Soumyadeep Chakraborty
Discussion: https://postgr.es/m/9d7e6ab0-8a53-ddb9-63cd-289bcb25fe0e@oss.nttdata.com

Discussion: https://postgr.es/m/CAMkU%3D1zxfA8_MGBW6sJMj54p8nPoe4bMb5LoG-rMYZVPq4j08Q%40mail.gmail.com
Author: Jeff Janes

When specified, WITH NO DATA does not insert any data into the relation
created, so skip checking for the insert permissions.  With WITH DATA or
WITH NO DATA, it is always required for the user to have CREATE
privileges on the schema targeted for the relation.

Note that plain CREATE TABLE AS or CREATE MATERIALIZED VIEW queries have
begun to work accidentally without INSERT privilege checks as of
874fe3ae, while using EXECUTE or EXPLAIN ANALYZE would fail with the ACL
check, so this makes the behavior for all the command flavors consistent
with each other.  This is arguably a bug fix, but there have been no
complaints about the current behavior either so stable branches are not
changed.

While on it, document properly the privileges requirements for each
commands with more tests for all the scenarios possible, and avoid a
useless bulk-insert allocation when using WITH NO DATA.

Author: Bharath Rupireddy
Reviewed-by: Anastasia Lubennikova, Michael Paquier
Discussion: https://postgr.es/m/CALj2ACWc3N8j0_9nMPz9wcAUnVcdKHzFdDZJ3hVFNEbqtcyG9w@mail.gmail.com

These flags should be independent: in particular an index AM should
be able to say that it supports include columns without necessarily
supporting multiple key columns.  The included-columns patch got
this wrong, possibly aided by the fact that it didn't bother to
update the documentation.

While here, clarify some text about amcanreturn, which was a little
vague about what should happen when amcanreturn reports that only
some of the index columns are returnable.

Noted while reviewing the SP-GiST included-columns patch, which
quite incorrectly (and unsafely) changed SP-GiST to claim
amcanmulticol = true as a workaround for this bug.

Backpatch to v11 where included columns were introduced.

Only a basic logic bug in a _bt_insertonpg() caller could lead to a
violation of this invariant (index corruption won't do it).  A "can't
happen" error seems inappropriate (it is arbitrary at best).

Demote the error to a simple assertion.  This matches similar nearby
sanity checks.

Buildfarm members that lack both HAVE_LOCALE_T and USE_ICU have been
complaining about pg_newlocale_from_collation's collcollate variable.
This is evidently fallout from commit 7d1297df, which removed the
only usage outside those two #ifdef'd code paths.  Mark the variable
pg_attribute_unused(), like its sibling collctype, which has been that
way for a long time.

The test inserts a row in primary server, waits until the insertion has
been replicated to a cascaded standby, and checks that it's visible there
by querying the cascaded standby. In order for that to work reliably, the
test needs to wait until the insertion WAL record has been fully replayed.

This should fix the occasional buildfarm failures. Diagnosis by Tom Lane.

Discussion: https://www.postgresql.org/message-id/606796.1605424022@sss.pgh.pa.us

Author: Erik Rijkers
Discussion: https://postgr.es/m/159fba265fe7c37334640fdc0444cc4b%40xs4all.nl

Obviously, in order to equality operator be satisfiable, target string must
contain all the trigrams of the search string.  On this base, we implement
equality operator in GiST/GIN indexes with recheck.

Discussion: https://postgr.es/m/CAOBaU_YWwtT7tdggtROacjdOdeYHCz-tmSwuC-j-TOG-g97J0w%40mail.gmail.com
Author: Julien Rouhaud
Reviewed-by: Tom Lane, Alexander Korotkov, Georgios Kokolatos, Erik Rijkers

This is mostly straightforward.  However, we disallow replacing
constraint triggers or changing the is-constraint property; perhaps
that can be added later, but the complexity versus benefit tradeoff
doesn't look very good.

Also, no special thought is taken here for whether replacing an
existing trigger should result in changes to queued-but-not-fired
trigger actions.  We just document that if you're surprised by the
results, too bad, don't do that.  (Note that any such pending trigger
activity would have to be within the current session.)

Takamichi Osumi, reviewed at various times by Surafel Temesgen,
Peter Smith, and myself

Discussion: https://postgr.es/m/0DDF369B45A1B44B8A687ED43F06557C010BC362@G01JPEXMBYT03

This started with the intent to explain that range upper bounds
are exclusive, which previously you could only find out by reading
the CREATE TABLE man page.  But I soon found that section 5.11
really could stand a fair amount of editorial attention.  It's
apparently been revised several times without much concern for
overall flow, nor careful copy-editing.

Back-patch to v11, which is as far as the patch goes easily.

Per gripe from Edson Richter.  Thanks to David Johnston for review.

Discussion: https://postgr.es/m/DM6PR13MB3988736CF8F5DC5720440231CFE60@DM6PR13MB3988.namprd13.prod.outlook.com

Author: Daniel Gustafsson
Discussion: https://postgr.es/m/C36ADFDF-D09A-4EE5-B186-CB46C3653F4C@yesql.se

This provides a handy way to get, say, the last field of the string.
Use of a negative index in this way has precedent in the nearby
left() and right() functions.

The implementation scans the string twice when N < -1, but it seems
likely that N = -1 will be the huge majority of actual use cases,
so I'm not really excited about adding complexity to avoid that.

Nikhil Benesch, reviewed by Jacob Champion; cosmetic tweakage by me

Discussion: https://postgr.es/m/cbb7f861-6162-3a51-9823-97bc3aa0b638@gmail.com

Apparently double-quotes are not allowed in filenames on Windows, either.

Per buildfarm.

These files are in compiled directories and install directories.

Reported-by: e.indrupskaya@postgrespro.ru

Discussion: https://postgr.es/m/160379609706.24746.7506163279454026608@wrigleys.postgresql.org

Backpatch-through: 9.5

Expression indexes can't benefit from pre-computed statistics on
columns.

Reported-by: Nikolay Samokhvalov

Discussion: https://postgr.es/m/CANNMO++5rw9RDA=p40iMVbMNPaW6O=S0AFzTU=KpYHRpCd1voA@mail.gmail.com

Author: Nikolay Samokhvalov, modified

Backpatch-through: 9.5

This was marked as BYTEA, but is more like TEXT, which is how we already
pass the history timeline file name.  Internally, we don't do any
encoding or bytea escape handling, but TEXT seems closest.  This should
cause no behavioral change.

Reported-by: Brar Piening

Discussion: https://postgr.es/m/6a1b9cd9-17e3-df67-be55-86102af6bdf5@gmx.de

Backpatch-through: master

On Windows, a filename cannot contain backslashes, because a backslash
is used directory separator. Remove tests I added in commit 9c4f5192
that tried to do that. We could perhaps use a SKIP block to only skip
them on Windows, but I'm not sure how exactly to formulate that, so just
remove the tests to make the buildfarm green again.

Per buildfarm.

Whether from size overflow in gistSplit or from secondary splits,
picksplit is (rarely) called with exactly two items to split.

Formerly, due to special-case handling of the last item, this would
lead to access to an uninitialized cache entry; prior to PG 13 this
might have been harmless or at worst led to an incorrect union datum,
but in 13 onwards it can cause a backend crash from using an
uninitialized pointer.

Repair by removing the special case, which was deemed not to have been
appropriate anyway. Backpatch all the way, because this bug has
existed since pg_trgm was added.

Per report on IRC from user "ftzdomino". Analysis and testing by me,
patch from Alexander Korotkov.

Discussion: https://postgr.es/m/87k0usfdxg.fsf@news-spur.riddles.org.uk

Using a hot standby server as the source has not been possible, because
pg_rewind creates a temporary table in the source system, to hold the
list of file ranges that need to be fetched. Refactor it to queue up the
file fetch requests in pg_rewind's memory, so that the temporary table
is no longer needed.

Also update the logic to compute 'minRecoveryPoint' correctly, when the
source is a standby server.

Reviewed-by: Kyotaro Horiguchi, Soumyadeep Chakraborty
Discussion: https://www.postgresql.org/message-id/0c5b3783-af52-3ee5-f8fa-6e794061f70d%40iki.fi

Various rules for optional keywords contained unnecessary rules and
type declarations.  Remove those, thus making the output a tiny bit
smaller.
Reviewed-by: Heikki Linnakangas <hlinnaka@iki.fi>
Discussion: https://www.postgresql.org/message-id/flat/e9eed669-e32d-6919-fed4-acc0daea857b%40enterprisedb.com

Backpatch-through: 13

Commit 1e53fe0e changed background processes so that they use
standard SIGHUP handler. Like that, this commit makes walreceiver
use standard SIGHUP and SIGTERM handlers, to simplify the code.

As the side effect of this commit, walreceiver can wake up and process
the configuration files promptly when receiving SIGHUP. Because the
standard SIGHUP handler sets the latch. On the other hand, previously
there could be a time lag between the receipt of SIGHUP and
the process of configuration files since the dedicated handler didn't
set the latch.

Author: Bharath Rupireddy, tweaked by Fujii Masao
Reviewed-by: Kyotaro Horiguchi, Fujii Masao
Discussion: https://postgr.es/m/CALj2ACXPorUqePswDtOeM_s82v9RW32E1fYmOPZ5NuE+TWKj_A@mail.gmail.com

911e7020 has introduced the opclass parameters including signature length
for a set of GiST opclasses.  Due to copy-pasting, macro for getting the
signature length in trgm_gist.c was named LTREE_GET_ASIGLEN().  Fix that by
renaming this macro to just GET_SIGLEN().

Backpatch-through: 13

Commit 6023b7ea allowed pg_stat_statements to track the number
of rows retrieved or affected by some utility commands including
CREATE MATERIALIZED VIEW. However it did not track the rowcount
of REFRESH MATERIALIZED VIEW. This commit allows pg_stat_statements
to track that.

To track that, this commit changes the query completion for
REFRESH MATERIALIZED VIEW so that it saves the rowcount. But note that
the rowcount is still not displayed in the command completion tag output.
That is, the display_rowcount flag of CMDTAG_REFRESH_MATERIALIZED_VIEW
command tag is left false in cmdtaglist.h. Otherwise, the change of
completion tag output might break applications using it.

Author: Katsuragi Yuta, Seino Yuki
Reviewed-by: Fujii Masao
Discussion: https://postgr.es/m/71f6bc72f8bbaa06e701f8bd2562c347@oss.nttdata.com
Discussion: https://postgr.es/m/aadbfba9-e4bb-9531-6b3a-d13c31c8f4fe@oss.nttdata.com

Attempting to take a base backup with Postgres linking to a build of
OpenSSL with FIPS enabled currently fails with or even without a backup
manifest requested because of this mandatory SHA256 initialization used
for the manifest file itself.  However, there is no need to do this
initialization at all if backup manifests are not needed because there
is no data to append to the manifest.

Note that being able to use backup manifests with OpenSSL+FIPS requires
a switch of the SHA2 implementation to use EVP, which would cause an ABI
breakage so this cannot be backpatched to 13 as it has been already
released, but at least avoiding this SHA256 initialization gives users
the possibility to take a base backup even when specifying --no-manifest
with pg_basebackup.

Author: Michael Paquier
Discussion: https://postgr.es/m/20201110020014.GE1887@paquier.xyz
Backpatch-through: 13