This section once started out small but has now grown quite a bit and
needs a bit of structure.

Rewrite as list, add documentation of EXCLUDING, and improve the
documentation of INCLUDING ALL instead of just listing all the options
again.

per report from Yugo Nagata that EXCLUDING was not documented, that part
reviewed by Daniel Gustafsson, most of the rewrite was by me

Since recent commit 1c7c317c, temporary relations cannot be mixed with
permanent relations within the same partition tree, and the same counts
for temporary relations created by other sessions, which the planner
simply discarded.  Instead be paranoid and issue an error, as those
should be blocked at definition time, at least for now.

At the same time, a test case is added to stress what has been moved
when expand_partitioned_rtentry gets called recursively but bumps on a
partitioned relation with no partitions which should be handled the same
way as the non-inheritance case.  This code may be reworked in a close
future, and covering this code path will limit surprises.

Reported-by: David Rowley
Author: David Rowley
Reviewed-by: Amit Langote, Robert Haas, Michael Paquier
Discussion: https://postgr.es/m/CAKJS1f_HyV1txn_4XSdH5EOhBMYaCwsXyAj6bHXk9gOu4JKsbw@mail.gmail.com

same as c4309f4a

This has been visibly a forgotten spot in the first implementation of
wait events for I/O added by 249cf070, and what has been missing is a
fsync call for WAL segments which is a wrapper reacting on the value of
GUC wal_sync_method.

Reported-by: Konstantin Knizhnik
Author: Konstantin Knizhnik
Reviewed-by: Craig Ringer, Michael Paquier
Discussion: https://postgr.es/m/4a243897-0ad8-f471-aa40-242591f2476e@postgrespro.ru

Reported-by: Dave Cramer
Author: Euler Taveira
Discussion: https://postgr.es/m/CADK3HHKnPGJDLhjOFBY6+70Wd14iEH8c2GKw7UrOuUHp_GNFrA@mail.gmail.com

These files are no longer requested on recovery (since
06f82b29), so the code for handling them
here is useless.

Author: Yugo Nagata <nagata@sraoss.co.jp>

When these programs call pg_catalog.set_config, they need to check for
PGRES_TUPLES_OK instead of PGRES_COMMAND_OK.  Fix for
5770172c.
Reported-by: Ideriha, Takeshi <ideriha.takeshi@jp.fujitsu.com>

While working on 1c7c317c and related things, which has clarified the
use of partitions with temporary tables, I have noticed that there could
be better coverage for inheritance trees mixing temporary and permanent
relations.  A lot of cross-checks happen in MergeAttributes() which is
not designed for this purpose, so the tests added in this commit will
make sure that any kind of future refactoring will limit the amount of
compatibility breakage.

Author: Michael Paquier
Reviewed-by: Ashutosh Bapat
Discussion: https://postgr.es/m/20180619022131.GE3314@paquier.xyz

In TAP test functions, that is, those that produce test results, locally
increment $Test::Builder::Level.  This has the effect that test failures
are reported at the callers location rather than somewhere in the test
support libraries.
Reviewed-by: Heikki Linnakangas <hlinnaka@iki.fi>

Deparsing logic in postgres_fdw for locking, FROM clause (alias) and Var
(column qualification) does not need to know the exact number of members
involved, which can be calculated with bms_num_members(), but just if
there is more than one relation involved, which is what bms_membership()
does.  The latter is more performant than the former so this shaves a
couple of cycles.

Author: Daniel Gustafsson
Reviewed-by: Ashutosh Bapat, Nathan Bossart
Discussion: https://postgr.es/m/C73594E0-2B67-4E10-BB35-CDE0E41CC384@yesql.se

Let the hacking begin ...

In a partition, row triggers that had been cloned from their parent
partitioned table would not be listed at all in psql's \d, which could
surprise users, per insistent complaint from Ashutosh Bapat (though his
aim was elsewhere).  The simplest possible fix, suggested by Peter
Eisentraut, seems to be to list triggers marked as internal if they have
a row in pg_depend that points to some other trigger.

Author: Álvaro Herrera
Discussion: https://postgr.es/m/20180618165910.p26vhk7dpq65ix54@alvherre.pgsql

The skip_build flag was not being passed correctly when recursing to
indexes on partitions, leading to attempts to rebuild indexes when they
were not yet ready to be rebuilt.

Reported-by: Rajkumar Raghuwanshi
Discussion: https://postgr.es/m/CAKcux6mxNCGsgATwf5CGMF8g4WSupCXicCVMeKUTuWbyxHOMsQ@mail.gmail.com

search.cpan.org has been EOL'd, with metacpan.org being the official
replacement to which URLs now redirect.  Update links to match the new
URL. Also update links to CPAN to use https as it will redirect from
http.

Author: Daniel Gustafsson
Discussion: https://postgr.es/m/B74C0219-6BA9-46E1-A524-5B9E8CD3BDB3@yesql.se

This includes code comments and documentation.  No backpatch as this is
cosmetic even if there are documentation changes which are user-facing.

Author: Daniel Gustafsson
Discussion: https://postgr.es/m/BB89928E-2BC7-489E-A5E4-6D204B3954CF@yesql.se

Author: Amit Langote
Discussion: https://postgr.es/m/b23dc88b-df41-ef07-22c5-12f77cf73b57@lab.ntt.co.jp

A slot can not be stored in a tuple but it's vice versa.

Reported-by: Ashutosh Bapat
Author: Ashutosh Bapat
Reviewed-by: Amit Kapila
Discussion: https://postgr.es/m/CAFjFpRcHhNhXdegyJv3KKDWrwO1_NB_KYZM_ZSDeMOZaL1A5jQ@mail.gmail.com

As added in 1de09ad8 the new functions
all accept signed integers as parameters. That's not great, because
it's perfectly reasonable to call them with unsigned parameters.
Unfortunately unsigned to signed conversion is not well defined, when
exceeding the range of the signed value.  That's presently not a
practical issue in postgres (among other reasons because we force
gcc's hand with -fwrapv).  But it's clearly not quite right.

Thus change the signatures to accept unsigned integers instead, signed
to unsigned conversion is always well defined. Also change the
backward compat pq_sendint() - while it's deprecated it seems better
to be consistent.

Per discussion between Andrew Gierth, Michael Paquier, Alvaro Herrera
and Tom Lane.

Reported-By: Andrew Gierth
Author: Andres Freund
Discussion: https://postgr.es/m/87r2m10zm2.fsf@news-spur.riddles.org.uk

The duplicated return clearly doesn't make sense / isn't
reachable. Likely introduced by me (Andres), while revising the code.

Author: Rushabh Lathia
Discussion: https://postgr.es/m/CAGPqQf2raxWOcbuTP36M1rEF3=Rfo7oD29K3psdyHMeE5swBRg@mail.gmail.com

Changed the name of few structure members for the sake of clarity and
removed spurious whitespace.

Reported-by: Amit Kapila
Author: Amit Kapila, based on suggestion by Andrew Dunstan
Reviewed-by: Alvaro Herrera
Discussion: https://postgr.es/m/CAA4eK1K2znsFpC+NQ9A4vxT4uDxADN4RmvHX0L6Y=aHVo9gB4Q@mail.gmail.com

Two closely related bugs are fixed.  First, xmin of logical slots was
advanced too early.  During xl_running_xacts processing, xmin of the
slot was set to the oldest running xid in the record, but that's wrong:
actually, snapshots which will be used for not-yet-replayed transactions
might consider older txns as running too, so we need to keep xmin back
for them.  The problem wasn't noticed earlier because DDL which allows
to delete tuple (set xmax) while some another not-yet-committed
transaction looks at it is pretty rare, if not unique: e.g. all forms of
ALTER TABLE which change schema acquire ACCESS EXCLUSIVE lock
conflicting with any inserts. The included test case (test_decoding's
oldest_xmin) uses ALTER of a composite type, which doesn't have such
interlocking.

To deal with this, we must be able to quickly retrieve oldest xmin
(oldest running xid among all assigned snapshots) from ReorderBuffer. To
fix, add another list of ReorderBufferTXNs to the reorderbuffer, where
transactions are sorted by base-snapshot-LSN.  This is slightly
different from the existing (sorted by first-LSN) list, because a
transaction can have an earlier LSN but a later Xmin, if its first
record does not obtain an xmin (eg. xl_xact_assignment).  Note this new
list doesn't fully replace the existing txn list: we still need that one
to prevent WAL recycling.

The second issue concerns SnapBuilder snapshots and subtransactions.
SnapBuildDistributeNewCatalogSnapshot never assigned a snapshot to a
transaction that is known to be a subtxn, which is good in the common
case that the top-level transaction already has one (no point in doing
so), but a bug otherwise.  To fix, arrange to transfer the snapshot from
the subtxn to its top-level txn as soon as the kinship gets known.
test_decoding's snapshot_transfer verifies this.

Also, fix a minor memory leak: refcount of toplevel's old base snapshot
was not decremented when the snapshot is transferred from child.

Liberally sprinkle code comments, and rewrite a few existing ones.  This
part is my (Álvaro's) contribution to this commit, as I had to write all
those comments in order to understand the existing code and Arseny's
patch.
Reported-by: Arseny Sher <a.sher@postgrespro.ru>
Diagnosed-by: Arseny Sher <a.sher@postgrespro.ru>
Co-authored-by: Arseny Sher <a.sher@postgrespro.ru>
Co-authored-by: Álvaro Herrera <alvherre@alvh.no-ip.org>
Reviewed-by: Antonin Houska <ah@cybertec.at>
Discussion: https://postgr.es/m/87lgdyz1wj.fsf@ars-thinkpad

6ca33a88 sets upper limit for vacuum_cleanup_index_scale_factor to
DBL_MAX.  DBL_MAX appears to be platform-dependent. That causes
many buildfarm animals to fail, because we check boundaries of
vacuum_cleanup_index_scale_factor in regression tests.

This commit changes upper limit from DBL_MAX to just "large enough"
limit, which was arbitrary selected as 1e10.

Author: Alexander Korotkov
Reported-by: Tom Lane, Darafei Praliaskouski
Discussion: https://postgr.es/m/CAPpHfdvewmr4PcpRjrkstoNn1n2_6dL-iHRB21CCfZ0efZdBTg%40mail.gmail.com
Discussion: https://postgr.es/m/CAC8Q8tLYFOpKNaPS_E7V8KtPdE%3D_TnAn16t%3DA3LuL%3DXjfOO-BQ%40mail.gmail.com

doc:  PG 11 relnotes: remove channel binding from major features

Also move to the source code section, and expand the paragraph

randomAccess parallel tuplesorts are disallowed because the leader would
try to write to its own leader tape, not because the leader would try to
write to a worker tape directly.

Cleanup from commit 9da0cc35.

Building a new nbtree index through incremental insertions would always
be slower than our actual approach of sorting using tuplesort,
assembling leaf pages from tuplesort output, and writing and WAL-logging
whole pages.  Remove a comment block from the Berkeley days claiming
that incremental insertions might be slightly faster with presorted
input.

Discussion: https://postgr.es/m/CAH2-WzmKs4mLAoFgJ3yHMRYc849efc=dw+pNRb3NEog2oJoCNw@mail.gmail.com

Concurrently with partitioned index development (commit 8b08f7d4),
the code to handle failure to rename indexes was refactored (commit
8b9e9644).  Turns out that that particular case was untested, which
naturally led it to be broken.  Add tests and the missing code line.
Co-authored-by: David Rowley <dgrowley@gmail.com>
Co-authored-by: Álvaro Herrera <alvherre@alvh.no-ip.org>
Reported-by: Rajkumar Raghuwanshi <rajkumar.raghuwanshi@enterprisedb.com>
Discussion: https://postgr.es/m/CAKcux6mfYMS3OX0ywjOiWiGSEKhJf-1zdeTceHFbd0mScUzU5A@mail.gmail.com

The backup history file has been no longer necessary for recovery
since the version 9.0. It's now basically just for informational purpose.
But previously the documentations still described that a recovery
requests the backup history file to proceed. The commit fixes this
documentation bug.

Back-patch to all supported versions.

Author: Yugo Nagata
Reviewed-by: Kyotaro Horiguchi
Discussion: https://postgr.es/m/20180626174752.0ce505e3.nagata@sraoss.co.jp

find_appinfos_by_relids had quite a large overhead when the number of
items in the append_rel_list was high, as it had to trawl through the
append_rel_list looking for AppendRelInfos belonging to the given
childrelids.  Since there can only be a single AppendRelInfo for each
child rel, it seems much better to store an array in PlannerInfo which
indexes these by child relid, making the function O(1) rather than O(N).
This function was only called once inside the planner, so just replace
that call with a lookup to the new array.  find_childrel_appendrelinfo
is now unused and thus removed.

This fixes a planner performance regression new to v11 reported by
Thomas Reiss.

Author: David Rowley
Reported-by: Thomas Reiss
Reviewed-by: Ashutosh Bapat
Reviewed-by: Álvaro Herrera
Discussion: https://postgr.es/m/94dd7a4b-5e50-0712-911d-2278e055c622@dalibo.com

Upper limits for vacuum_cleanup_index_scale_factor GUC and reloption
were initially set to 100.0 in 857f9c36.  However, after further
discussion, it appears that some users like to disable B-tree cleanup
index scan completely (assuming there are no deleted pages).

vacuum_cleanup_index_scale_factor is used barely to protect against
stalled index statistics.  And after detailed consideration it appears
that risk of stalled index statistics is low.  And it would be nice to
allow advanced users setting higher values of
vacuum_cleanup_index_scale_factor.  So, set upper limit for these
GUC and reloption to DBL_MAX.

Author: Alexander Korotkov
Reviewed-by: Masahiko Sawada
Discussion: https://postgr.es/m/CAC8Q8tJCb%3DgxhzcV7T6ctx7PY-Ux1oA-AsTJc6cAVNsQiYcCzA%40mail.gmail.com

The previous message for SPI_ERROR_TRANSACTION claimed "cannot begin/end
transactions in PL/pgSQL", but that is no longer true.  Nevertheless,
the error can still happen, so reword the messages.  The error cases in
exec_prepare_plan() could never happen, so remove them.