Most seriously, fix use of incorrect block ID, per a report from
Jeff Janes that it causes a crash and a diagnosis from Amit Kapila.

Improve consistency between the hash and btree versions of this
code by adding back a PANIC that btree has, and by registering
data in the xlog record in the same way, per complaints from
Jeff Janes and Amit Kapila.

Tidy up some minor cosmetic points, per complaints from Amit
Kapila.

Patch by Ashutosh Sharma, reviewed by Amit Kapila, and tested by
Jeff Janes.

Discussion: http://postgr.es/m/CAMkU=1w-9Qe=Ff1o6bSaXpNO9wqpo7_9GL8_CVhw4BoVVHasqg@mail.gmail.com

If file was created/deleted just before powerloss it's possible that
file system will miss that. To prevent it, call fsync() where creating/
unlinkg file is critical.

Author: Michael Paquier
Reviewed-by: Ashutosh Bapat, Takayuki Tsunakawa, me

The code for the reworked n-distinct estimation on commit 7b504eb2 was
written differently in a previous version of the patch, prior to commit;
on rewriting it, we missed updating an initializer.  This caused the
code to (mistakenly) apply a fudge factor even in the case where a
single value is applied, leading to incorrect results.

This means that the 'relvarcount' variable name is now wrong.  Add a
comment to try and make the situation clearer, and remove an incorrect
comment I added.

Problem noticed, and code patch, by Tomas Vondra.  Additional commentary
by Álvaro.

Previous coding uses three nested loops which obviously were a pain for
large number of table's children. Patch replaces inner loop with
a hashmap.

Author: Aleksander Alekseev
Reviewed-by: me

https://commitfest.postgresql.org/13/1058/

Commit e259e1f7 was faulty and created
some broken output.  This one fixes it better.

As suggested by Tom Lane, avoid printing specific estimated cost values,
because they vary across architectures; instead, verify plan shapes (in
this case, HashAggregate vs. GroupAggregate), as we do in other planner
tests.

We can now remove expected/stats_ext_1.out.

Author: Tomas Vondra

Instead of

    plan = plpy.prepare(...)
    res = plpy.execute(plan, ...)

you can now write

    plan = plpy.prepare(...)
    res = plan.execute(...)

or even

    res = plpy.prepare(...).execute(...)

and similarly for the cursor() method.

This is more in object oriented style, and makes the hybrid nature of
the existing execute() function less confusing.
Reviewed-by: Andrew Dunstan <andrew.dunstan@2ndquadrant.com>

Patch introduces a hash map reloid -> PgStat_TableStatus which improves
performance in case of large number of tables/partitions.

Author: Aleksander Alekseev
Reviewed-by: Andres Freund, Anastasia Lubennikova, Tels, me

https://commitfest.postgresql.org/13/1058/

Amit Langote

Discussion: http://postgr.es/m/a6f99cdb-21e7-1d65-1381-91f2cfa156e2@lab.ntt.co.jp

Remove some <note> tags that make this too "loud".  Fix some typos.

Amit Langote, with a few minor corrections by me

Discussion: http://postgr.es/m/a6f99cdb-21e7-1d65-1381-91f2cfa156e2@lab.ntt.co.jp

The previous logic was wrong when the value was NULL but there was
no partition for NULL.

Amit Langote, reviewed by Jeevan Ladhe

Discussion: http://postgr.es/m/d64f8498-70eb-3c88-b56d-c54fd3b0500f@lab.ntt.co.jp

ON CONFLICT .. DO UPDATE still doesn't work, for lack of a way of
enforcing uniqueness across partitions, but we can still allow this
case.

Amit Langote, per discussion with Peter Geoghegan.  Additional
wordsmithing by me.

Discussion: http://postgr.es/m/CAA-aLv7Z4uygtq-Q5CvDi9Y=VZxUyEnuWjL=EwCfOof=L04hgg@mail.gmail.com

The previous default 'pg_log' might have indicated by its "pg_" prefix
that it is an internal system directory.  The new default is more in
line with the typical naming of directories with user-facing log files.
Together with the renaming of pg_clog and pg_xlog, this should clear up
that difference.

Author: Andreas Karlsson <andreas@proxel.se>

When creating an unshared TIDBitmap, we pass MCXT_ALLOC_HUGE to allow
allocations >1GB, so by analogy we pass DSA_ALLOC_HUGE for a shared
TIDBitmap.

Bug introduced by commit 98e6e890.
Report by Rafia Sabih, fix by Dilip Kumar, adjusted by me.

Discussion: http://postgr.es/m/CAOGQiiPpSnkuKq+oUK_bvQFg2EPGFPN8RwgxTgBa6HU_kQa3EA@mail.gmail.com

Fix all perlcritic warnings of severity level 5, except in
src/backend/utils/Gen_dummy_probes.pl, which is automatically generated.
Reviewed-by: Dagfinn Ilmari Mannsåker <ilmari@ilmari.org>
Reviewed-by: Daniel Gustafsson <daniel@yesql.se>

Per buildfarm members dromedary and arapaima.

There was a thinko whereby we tested the wrong tuple after fetching it
from cache; avoid that by using generate_relation_name instead, which is
simpler.  Also, the statistics name was not qualified, so add that.  (It
could be argued that qualification should be conditional on the schema
not being on search path.  We can add that later, but at least this form
is correct.)

Author: David Rowley, Álvaro Herrera
Discussion: https://postgr.es/m/CAKJS1f8RjLeVZJ2+93pdQGuZJeBF-ifsHaFMR-q-6-Z0qxA8cA@mail.gmail.com

This extends the Aggregate node with two new features: HashAggregate
can now run multiple hashtables concurrently, and a new strategy
MixedAggregate populates hashtables while doing sorted grouping.

The planner will now attempt to save as many sorts as possible when
planning grouping sets queries, while not exceeding work_mem for the
estimated combined sizes of all hashtables used.  No SQL-level changes
are required.  There should be no user-visible impact other than the
new EXPLAIN output and possible changes to result ordering when ORDER
BY was not used (which affected a few regression tests).  The
enable_hashagg option is respected.

Author: Andrew Gierth
Reviewers: Mark Dilger, Andres Freund
Discussion: https://postgr.es/m/87vatszyhj.fsf@news-spur.riddles.org.uk

Cut-and-paste led to something silly.

Ashutosh Sharma, reviewed by Amit Kapila and by me

Discussion: http://postgr.es/m/CAE9k0PmUbvQSBY7kwN_OkuqBYyHRXBX-c1ZkuAgR5vgF0GeWzQ@mail.gmail.com

Previously, auxiliary processes and background workers not connected
to a database (such as the logical replication launcher) weren't
shown.  Include them, so that we can see the associated wait state
information.  Add a new column to identify the processes type, so that
people can filter them out easily using SQL if they wish.

Before this patch was written, there was discussion about whether we
should expose this information in a separate view, so as to avoid
contaminating pg_stat_activity with things people might not want to
see.  But putting everything in pg_stat_activity was a more popular
choice, so that's what the patch does.

Kuntal Ghosh, reviewed by Amit Langote and Michael Paquier.  Some
revisions and bug fixes by me.

Discussion: http://postgr.es/m/CA+TgmoYES5nhkEGw9nZXU8_FhA8XEm8NTm3-SO+3ML1B81Hkww@mail.gmail.com

In commit b8d7f053, we needed to fix ExecEvalWholeRowVar to not change
the state of the slot it's copying.  The initial quick hack at that
required two rounds of tuple construction, which is not very nice.
To fix, add another primitive to tuptoaster.c that does precisely what
we need.  (I initially tried to do this by refactoring one of the
existing functions into two pieces; but it looked like that might hurt
performance for the existing case, and the amount of code that could
be shared is not very large, so I gave up on that.)

Discussion: https://postgr.es/m/26088.1490315792@sss.pgh.pa.us

Structure tag cannot be the same as a typedef that is a pointer to that
struct.

Change one more place where ExecInitCheck/ExecPrepareCheck's insistence
on getting implicit-AND-format quals wasn't really helpful, because the
caller had to do make_ands_implicit() for no reason that it cared about.
Using ExecPrepareExpr directly simplifies the code and saves cycles.

The only remaining use of these functions is to process
resultRelInfo->ri_PartitionCheck quals.  However, implicit-AND format
does seem to be what we want for that, so leave it alone.

Fix an incorrect assert condition (noted by Coverity), and spell the new
name of the function correctly.  Typos introduced in commit 7c4f5240.

Michael Paquier

The compiler is entitled to store a char[] local variable with no
particular alignment requirement.  Our RADIUS code cavalierly took such
a local variable and cast its address to a struct type that does have
alignment requirements.  On an alignment-picky machine this would lead
to bus errors.  To fix, declare the local variable honestly, and then
cast its address to char * for use in the I/O calls.

Given the lack of field complaints, there must be very few if any
people affected; but nonetheless this is a clear portability issue,
so back-patch to all supported branches.

Noted while looking at a Coverity complaint in the same code.

Failure to free serveraddrs pointed out by Coverity, failure to close
socket noted by code-reading.  These bugs seem to be quite old, but
given the low probability of taking these error-exit paths and the
minimal consequences of the leaks (since the process would presumably
exit shortly anyway), it doesn't seem worth back-patching.

Michael Paquier and Tom Lane

Both Andres and I were happy with "*op->resvalue = *op->resvalue;",
but Coverity isn't; and it has a point, because some compilers might
not be smart enough to elide that.  So remove it.  In passing, also
avoid doing unnecessary assignments to *op->resnull when it's already
known to have the right value.

"xref to REFSECT1 unsupported" with the DSSSL stylesheets.
Reported-by: Devrim Gündüz <devrim@gunduz.org>

In the DSSSL stylesheets, we had an extensive customization of the
bibliography rendering.  Since the bibliography isn't that used much, it
doesn't seem worth doing an elaborate porting of that to XSLT.  So this
just moves some things around, removes some unused things, and does some
minimal XSLT stylesheet customizations to make things look clean.

Fix a few stray references to expression eval functions that don't
exist anymore or don't take the same input representation they used to.

Noticed by Coverity

Due to b8d7f053 some permission checks are now happening even on
empty tables, and some of the checks move around.

Discussion: https://postgr.es/m/95bdb608-093c-160f-c6be-983a36ccd7f9@joeconway.com

The previous code still contained expression evaluation time support
for CaseExprs without a defresult.  But transformCaseExpr() creates a
default expression if necessary.

Author: Andres Freund
Discussion: https://postgr.es/m/4834.1490480275@sss.pgh.pa.us

Should have been in commit b8d7f053,
but passing the patch back and forth as a patch seems to have dropped
that metadata.

This replaces the old, recursive tree-walk based evaluation, with
non-recursive, opcode dispatch based, expression evaluation.
Projection is now implemented as part of expression evaluation.

This both leads to significant performance improvements, and makes
future just-in-time compilation of expressions easier.

The speed gains primarily come from:
- non-recursive implementation reduces stack usage / overhead
- simple sub-expressions are implemented with a single jump, without
  function calls
- sharing some state between different sub-expressions
- reduced amount of indirect/hard to predict memory accesses by laying
  out operation metadata sequentially; including the avoidance of
  nearly all of the previously used linked lists
- more code has been moved to expression initialization, avoiding
  constant re-checks at evaluation time

Future just-in-time compilation (JIT) has become easier, as
demonstrated by released patches intended to be merged in a later
release, for primarily two reasons: Firstly, due to a stricter split
between expression initialization and evaluation, less code has to be
handled by the JIT. Secondly, due to the non-recursive nature of the
generated "instructions", less performance-critical code-paths can
easily be shared between interpreted and compiled evaluation.

The new framework allows for significant future optimizations. E.g.:
- basic infrastructure for to later reduce the per executor-startup
  overhead of expression evaluation, by caching state in prepared
  statements.  That'd be helpful in OLTPish scenarios where
  initialization overhead is measurable.
- optimizing the generated "code". A number of proposals for potential
  work has already been made.
- optimizing the interpreter. Similarly a number of proposals have
  been made here too.

The move of logic into the expression initialization step leads to some
backward-incompatible changes:
- Function permission checks are now done during expression
  initialization, whereas previously they were done during
  execution. In edge cases this can lead to errors being raised that
  previously wouldn't have been, e.g. a NULL array being coerced to a
  different array type previously didn't perform checks.
- The set of domain constraints to be checked, is now evaluated once
  during expression initialization, previously it was re-built
  every time a domain check was evaluated. For normal queries this
  doesn't change much, but e.g. for plpgsql functions, which caches
  ExprStates, the old set could stick around longer.  The behavior
  around might still change.

Author: Andres Freund, with significant changes by Tom Lane,
	changes by Heikki Linnakangas
Reviewed-By: Tom Lane, Heikki Linnakangas
Discussion: https://postgr.es/m/20161206034955.bh33paeralxbtluv@alap3.anarazel.de

As explained at the head of parallel_schedule, we place an arbitrary limit
of 20 test cases per parallel group.  Commit c7a9fa39 overlooked this.

Least messy solution seems to be to move the "comments" test to the next
group, since it doesn't really belong in a group of datatype tests anyway.

Commit e3920ac8 created "regress_subscription_user2" in subscription.sql,
but forgot to drop it, causing the regression tests to fail if run twice
without re-initdb'ing.

If the upstream walsender is using a physical replication slot, store the
catalog_xmin in the slot's catalog_xmin field. If the upstream doesn't use a
slot and has only a PGPROC entry behaviour doesn't change, as we store the
combined xmin and catalog_xmin in the PGPROC entry.

Author: Craig Ringer