Typedef name should be both unique and non-intersect with variable names
across all the sources.  That makes both pg_indent and debuggers happy.

Discussion: https://postgr.es/m/23865.1552936099%40sss.pgh.pa.us

Running ALTER TABLE on any table will check if a TOAST table needs to be
added.  On shared tables, this would previously fail, thus effectively
disabling ALTER TABLE for those tables.  On (non-shared) system
catalogs, on the other hand, it would add a TOAST table, even though we
don't really want TOAST tables on some system catalogs.  In some cases,
it would also fail with an error "AccessExclusiveLock required to add
toast table.", depending on what locks the ALTER TABLE actions had
already taken.

So instead, just ignore attempts to add TOAST tables to such tables,
outside of bootstrap mode, pretending they don't need one.

This allows running ALTER TABLE on such tables without messing up the
TOAST situation.  Legitimate uses for ALTER TABLE on system catalogs
include setting reloptions (say, fillfactor or autovacuum settings).

(All this still requires allow_system_table_mods, which is independent
of this.)

Discussion: https://www.postgresql.org/message-id/flat/e49f825b-fb25-0bc8-8afc-d5ad895c7975@2ndquadrant.com

Unrecognized attribute names are supposed to be ignored.  But the code
would error out on an unrecognized attribute value even if it did not
recognize the attribute name.  So unrecognized attributes wouldn't
really be ignored unless the value happened to be one that matched a
recognized value.  This would break some important cases where the
attribute would be processed by ucol_open() directly.  Fix that and
add a test case.

The restructured code should also avoid compiler warnings about
initializing a UColAttribute value to -1, because the type might be an
unsigned enum.  (reported by Andres Freund)

Commit 6776142a failed to do this,
and the buildfarm broke.

Patch by me, per advice from Tom Lane and Michael Paquier.

Discussion: http://postgr.es/m/13988.1552960403@sss.pgh.pa.us

Aggregates have acquired a dozen or so optional attributes in recent
years for things like parallel query and moving-aggregate mode; the
lack of an OR REPLACE option to add or change these for an existing
agg makes extension upgrades gratuitously hard. Rectify.

Commit f2dec34e changed things so that printtup's output stringinfo
buffer was allocated outside the per-row temporary context, not inside
it.  This creates a need to free that buffer explicitly when the temp
context is freed, but that was overlooked.  In most cases, this is all
happening inside a portal or executor context that will go away shortly
anyhow, but that's not always true.  Notably, the stringinfo ends up
getting leaked when JDBC uses row-at-a-time fetches.  For a query
that returns wide rows, that adds up after awhile.

Per bug #15700 from Matthias Otterbach.  Back-patch to v11 where the
faulty code was added.

Discussion: https://postgr.es/m/15700-8c408321a87d56bb@postgresql.org

I screwed this up in ad0bda5d.

Reported-By: Jie Zhang, Michael Paquier, Etsuro Fujita
Discussion: https://postgr.es/m/1396E95157071C4EBBA51892C5368521017F2DA203@G08CNEXMBPEKD02.g08.fujitsu.local

I (Andres) missed this in 578b2297.

Author: John Naylor
Discussion: https://postgr.es/m/CACPNZCtd+ckUgibRFs9KewK4Yr5rj3Oipefquupw+XJZebFhrA@mail.gmail.com

We should try to prewarm each database only once.  Otherwise, if
prewarming fails for some reason, it will just keep retrying in an
infnite loop.  This can happen if, for example, the database has been
dropped.  The existing code was intended to implement the try-once
behavior, but failed to do so because it neglected to set
worker.bgw_restart_time to BGW_NEVER_RESTART.

Mithun Cy, per a report from Hans Buschmann

Discussion: http://postgr.es/m/CA+hUKGKpQJCWcgyy3QTC9vdn6uKAR_8r__A-MMm2GYfj45caag@mail.gmail.com

Like commit f41551f6, this aims
to make it easier to add non-Boolean options to VACUUM (or, in
this case, to ANALYZE).  Instead of building up a bitmap of
options directly in the parser, build up a list of DefElem
objects and let ExecVacuum() sort it out; right now, we make
no use of the fact that a DefElem can carry an associated value,
but it will be easy to make that change in the future.

Masahiko Sawada

Discussion: http://postgr.es/m/CAD21AoATE4sn0jFFH3NcfUZXkU2BMbjBWB_kDj-XWYA-LXDcQA@mail.gmail.com

Many places need both, so this allows a few functions to take one
fewer parameter.  More importantly, as soon as we add a VACUUM
option that takes a non-Boolean parameter, we need to replace
'int options' with a struct, and it seems better to think
of adding more fields to VacuumParams rather than passing around
both VacuumParams and a separate struct as well.

Patch by me, reviewed by Masahiko Sawada

Discussion: http://postgr.es/m/CA+Tgmob6g6-s50fyv8E8he7APfwCYYJ4z0wbZC2yZeSz=26CYQ@mail.gmail.com

In RI_FKey_pk_upd_check_required(), we check among other things
whether the old and new key are equal, so that we don't need to run
cascade actions when nothing has actually changed.  This was using the
equality operator.  But the effect of this is that if a value in the
primary key is changed to one that "looks" different but compares as
equal, the update is not propagated.  (Examples are float -0 and 0 and
case-insensitive text.)  This appears to violate the SQL standard, and
it also behaves inconsistently if in a multicolumn key another key is
also updated that would cause the row to compare as not equal.

To fix, if we are looking at the PK table in ri_KeysEqual(), then do a
bytewise comparison similar to record_image_eq() instead of using the
equality operators.  This only makes a difference for ON UPDATE
CASCADE, but for consistency we treat all changes to the PK the same.  For
the FK table, we continue to use the equality operators.

Discussion: https://www.postgresql.org/message-id/flat/3326fc2e-bc02-d4c5-e3e5-e54da466e89a@2ndquadrant.com

It has never been used.

As it was agreed to worsen the code readability.

Discussion: https://postgr.es/m/ecfcfb5f-3233-eaa9-0c83-07056fb49a83%402ndquadrant.com

ce6afc68 has begun the refactoring work by plugging pg_rewind into a
central routine to update the control file, and left around two extra
copies, with one in xlog.c for the backend and one in pg_resetwal.c.  By
adding an extra option to the central routine in controldata_utils.c to
control if a flush of the control file needs to be done, it is proving
to be straight-forward to make xlog.c and pg_resetwal.c use the central
code path at the condition of moving the wait event tracking there.
Hence, this allows to have only one central code path to update the
control file, shaving the code from the duplicates.

This refactoring actually fixes a problem in pg_resetwal.  Previously,
the control file was first removed before being recreated.  So if a
crash happened between the moment the file was removed and the moment
the file was created, then it would have been possible to not have a
control file anymore in the database folder.

Author: Fabien Coelho
Reviewed-by: Michael Paquier
Discussion: https://postgr.es/m/alpine.DEB.2.21.1903170935210.2506@lancre

This fixes an issue introduced by 266b6acb, which has added filters to
exclude file patterns on the target and source data directories to
reduce the number of files transferred.  Filters get applied to both
the target and source data files, and include pg_internal.init which is
present for each database once relations are created on it.  However, if
the target differed from the source with at least one new database with
relations, the rewind would fail due to the exclusion filters applied on
the target files, causing pg_internal.init to still be present on the
target database folder, while its contents should have been completely
removed so as there is nothing remaining inside at the time of the
folder deletion.

Applying exclusion filters on the source files is fine, because this way
the amount of data copied from the source to the target is reduced.  And
actually, not applying the filters on the target is what pg_rewind
should do, because this causes such files to be automatically removed
during the rewind on the target.  Exclusion filters apply to paths which
are removed or recreated automatically at startup, so removing all those
files on the target during the rewind is a win.

The existing set of TAP tests already stresses the rewind of databases,
but it did not include any tables on those newly-created databases.
Creating extra tables in this case is enough to reproduce the failure,
so the existing tests are extended to close the gap.

Reported-by: Mithun Cy
Author: Michael Paquier
Discussion: https://postgr.es/m/CADq3xVYt6_pO7ZzmjOqPgY9HWsL=kLd-_tNyMtdfjKqEALDyTA@mail.gmail.com
Backpatch-through: 11

pg_checksums is compiled with a given block size and has a hard
dependency to it per the way checksums are calculated via
checksum_impl.h, and trying to use the tool on a data folder which has
not the same block size would result in incorrect checksum calculations
and/or block read errors, meaning that the data folder is corrupted.
This is harmless as checksums are only checked now, but very confusing
for the user so issue an error properly if the block size used at
compilation and the block size used in the data folder do not match.

Reported-by: Sergei Kornilov
Author: Michael Banck, Michael Paquier
Reviewed-by: Fabien Coelho, Magnus Hagander
Discussion: https://postgr.es/m/20190317054657.GA3357@paquier.xyz
ackpatch-through: 11

Instead of tricky assignment to {0} introduce special macros, which
explicitly initialize every field.

Discussion: https://postgr.es/m/CAEeOP_a-Pfy%3DU9-f%3DgQ0AsB8FrxrC8xCTVq%2BeO71-2VoWP5cag%40mail.gmail.com
Author: Mark G

Because they fail build of jsonpath_scan.c.

Reported-by: Jeff Janes, Tom Lane
Discussion: https://postgr.es/m/CAMkU%3D1w1qBvoW82ZTFpAKae027R-2OHw-m6ALe0VQRNAFueBVA%40mail.gmail.com

Starting in ICU 54, collation customization attributes can be
specified in the locale string, for example
"@colStrength=primary;colCaseLevel=yes".  Add support for this for
older ICU versions as well, by adding some minimal parsing of the
attributes in the locale string and calling ucol_setAttribute() on
them.  This is essentially what never ICU versions do internally in
ucol_open().  This was we can offer this functionality in a consistent
way in all ICU versions supported by PostgreSQL.

Also add some tests for ICU collation customization.
Reported-by: Daniel Verite <daniel@manitou-mail.org>
Discussion: https://www.postgresql.org/message-id/0270ebd4-f67c-8774-1a5a-91adfb9bb41f@2ndquadrant.com

Warning was observed in gcc 4.4.6, gcc 4.4.7 and probably others.

Reported-by: Tom Lane
Discussion: https://postgr.es/m/25151.1552751426%40sss.pgh.pa.us

see 8e93a516

It looks like we can leave in most of the test cases for Infinity/NaN
inputs, but buildfarm member jacana gets the wrong answer for acosh(Inf).
It's not worth carrying a variant expected file for that, so just disable
that one test.

Discussion: https://postgr.es/m/E1h3nUY-0000sM-Vf@gemulon.postgresql.org

Per buildfarm.  See commit 41c912ca for precedent.

Add support of numeric error suppression to jsonpath as it's required by
standard.  This commit doesn't use PG_TRY()/PG_CATCH() in order to implement
that.  Instead, it provides internal versions of numeric functions used, which
support error suppression.

Discussion: https://postgr.es/m/fcc6fc6a-b497-f39a-923d-aa34d0c588e8%402ndQuadrant.com
Author: Alexander Korotkov, Nikita Glukhov
Reviewed-by: Tomas Vondra

SQL 2016 standards among other things contains set of SQL/JSON features for
JSON processing inside of relational database.  The core of SQL/JSON is JSON
path language, allowing access parts of JSON documents and make computations
over them.  This commit implements partial support JSON path language as
separate datatype called "jsonpath".  The implementation is partial because
it's lacking datetime support and suppression of numeric errors.  Missing
features will be added later by separate commits.

Support of SQL/JSON features requires implementation of separate nodes, and it
will be considered in subsequent patches.  This commit includes following
set of plain functions, allowing to execute jsonpath over jsonb values:

 * jsonb_path_exists(jsonb, jsonpath[, jsonb, bool]),
 * jsonb_path_match(jsonb, jsonpath[, jsonb, bool]),
 * jsonb_path_query(jsonb, jsonpath[, jsonb, bool]),
 * jsonb_path_query_array(jsonb, jsonpath[, jsonb, bool]).
 * jsonb_path_query_first(jsonb, jsonpath[, jsonb, bool]).

This commit also implements "jsonb @? jsonpath" and "jsonb @@ jsonpath", which
are wrappers over jsonpath_exists(jsonb, jsonpath) and jsonpath_predicate(jsonb,
jsonpath) correspondingly.  These operators will have an index support
(implemented in subsequent patches).

Catversion bumped, to add new functions and operators.

Code was written by Nikita Glukhov and Teodor Sigaev, revised by me.
Documentation was written by Oleg Bartunov and Liudmila Mantrova.  The work
was inspired by Oleg Bartunov.

Discussion: https://postgr.es/m/fcc6fc6a-b497-f39a-923d-aa34d0c588e8%402ndQuadrant.com
Author: Nikita Glukhov, Teodor Sigaev, Alexander Korotkov, Oleg Bartunov, Liudmila Mantrova
Reviewed-by: Tomas Vondra, Andrew Dunstan, Pavel Stehule, Alexander Korotkov

When libpq is loaded in the server (for instance, by
libpqwalreceiver), it may use libpq environment variables set in the
postmaster environment for connection parameter defaults.  This has
some confusing effects in our test suites.  For example, the TAP test
infrastructure sets PGAPPNAME to allow identifying clients in the
server log.  But this environment variable is also inherited by
temporary servers started with pg_ctl and is then in turn used by
libpqwalreceiver as the application_name for connecting to remote
servers where it then shows up in pg_stat_replication and is relevant
for things like synchronous_standby_names.  Replication already has a
suitable default for application_name, and overriding that
accidentally then requires the individual test cases to re-override
that, which is all very confusing and unnecessary.

To fix, unset PGAPPNAME temporarily before running pg_ctl start or
restart in the tests.

More comprehensive approaches like unsetting all environment variables
in pg_ctl were considered but might be too complicated to achieve
portably.

The now unnecessary re-overriding of application_name by test cases is
also removed.
Reviewed-by: Noah Misch <noah@leadboat.com>
Discussion: https://www.postgresql.org/message-id/flat/33383613-690e-6f1b-d5ba-4957ff40f6ce@2ndquadrant.com

Fixed-by: Kuroda-san <kuroda.hayato@jp.fujitsu.com>

Author: John Naylor
Discussion: https://postgr.es/m/CACPNZCswjyGJxTT=mxHgK=Z=mJ9uJ4WEx_UO=bNwpR_i0EaHHg@mail.gmail.com

Some buildfarm members using CLOBBER_CACHE_ALWAYS have been having OOM
problems of late.  Commit 2455ab48 addressed this problem by recovering
space transiently used within RelationBuildPartitionDesc, but it turns
out that leaves quite a lot on the table, because other subroutines of
RelationBuildDesc also leak memory like mad.  Let's move the temp-context
management into RelationBuildDesc so that leakage from the other
subroutines is also recovered.

I examined this issue by arranging for postgres.c to dump the size of
MessageContext just before resetting it in each command cycle, and
then running the update.sql regression test (which is one of the two
that are seeing buildfarm OOMs) with and without CLOBBER_CACHE_ALWAYS.
Before 2455ab48, the peak space usage with CCA was as much as 250MB.
That patch got it down to ~80MB, but with this patch it's about 0.5MB,
and indeed the space usage now seems nearly indistinguishable from a
non-CCA build.

RelationBuildDesc's traditional behavior of not worrying about leaking
transient data is of many years' standing, so I'm pretty hesitant to
change that without more evidence that it'd be useful in a normal build.
(So far as I can see, non-CCA memory consumption is about the same with
or without this change, whuch if anything suggests that it isn't useful.)
Hence, configure the patch so that we recover space only when
CLOBBER_CACHE_ALWAYS or CLOBBER_CACHE_RECURSIVELY is defined.  However,
that choice can be overridden at compile time, in case somebody would
like to do some performance testing and try to develop evidence for
changing that decision.

It's possible that we ought to back-patch this change, but in the
absence of back-branch OOM problems in the buildfarm, I'm not in
a hurry to do that.

Discussion: https://postgr.es/m/CA+TgmoY3bRmGB6-DUnoVy5fJoreiBJ43rwMrQRCdPXuKt4Ykaw@mail.gmail.com

The trigger tests for PL/Tcl were spread aroud pltcl_setup.sql and
pltcl_queries.sql, mixed with other tests, which makes them hard to
follow and edit.  Move all the trigger-related pieces to a new file
pltcl_trigger.sql.  This also makes the test setup more similar to
plperl and plpython.

Add a separate walreceiver API function walrcv_server_version() to get
the version of the remote server, instead of doing it as part of
walrcv_identify_system().  This allows the server version to be
available even for uses that don't call IDENTIFY_SYSTEM, and it seems
cleaner anyway.

This is for an upcoming patch, not currently used.
Reviewed-by: Michael Paquier <michael@paquier.xyz>
Discussion: https://www.postgresql.org/message-id/20190115071359.GF1433@paquier.xyz

Author: Sho Kato
Reviewed-by: Kyotaro Horiguchi
Discussion: https://postgr.es/m/25C1C6B2E7BE044889E4FE8643A58BA963E1D03D@G01JPEXMBKW03

Previously, the SERIALIZABLE isolation level prevented parallel query
from being used.  Allow the two features to be used together by
sharing the leader's SERIALIZABLEXACT with parallel workers.

An extra per-SERIALIZABLEXACT LWLock is introduced to make it safe to
share, and new logic is introduced to coordinate the early release
of the SERIALIZABLEXACT required for the SXACT_FLAG_RO_SAFE
optimization, as follows:

The first backend to observe the SXACT_FLAG_RO_SAFE flag (set by
some other transaction) will 'partially release' the SERIALIZABLEXACT,
meaning that the conflicts and locks it holds are released, but the
SERIALIZABLEXACT itself will remain active because other backends
might still have a pointer to it.

Whenever any backend notices the SXACT_FLAG_RO_SAFE flag, it clears
its own MySerializableXact variable and frees local resources so that
it can skip SSI checks for the rest of the transaction.  In the
special case of the leader process, it transfers the SERIALIZABLEXACT
to a new variable SavedSerializableXact, so that it can be completely
released at the end of the transaction after all workers have exited.

Remove the serializable_okay flag added to CreateParallelContext() by
commit 9da0cc35, because it's now redundant.

Author: Thomas Munro
Reviewed-by: Haribabu Kommi, Robert Haas, Masahiko Sawada, Kevin Grittner
Discussion: https://postgr.es/m/CAEepm=0gXGYhtrVDWOTHS8SQQy_=S9xo+8oCxGLWZAOoeJ=yzQ@mail.gmail.com

If a heap on the old cluster has 4 pages or fewer, and the old cluster
was PG v11 or earlier, don't copy or link the FSM. This will shrink
space usage for installations with large numbers of small tables.

This will allow pg_upgrade to take advantage of commit b0eaa4c5 where
we have avoided creation of the free space map for small heap relations.

Author: John Naylor
Reviewed-by: Amit Kapila
Discussion: https://postgr.es/m/CACPNZCu4cOdm3uGnNEGXivy7Gz8UWyQjynDpdkPGabQ18_zK6g%40mail.gmail.com