Correct volatility markings of a few json functions.

json_agg and json_object_agg and their associated transition functions
should have been marked as stable rather than immutable, as they call IO
functions indirectly. Changing this probably isn't going to make much
difference, as you can't use an aggregate function in an index
expression, but we should be correct nevertheless.

json_object, on the other hand, should be marked immutable rather than
stable, as it does not call IO functions.

As discussed on -hackers, this change is being made without bumping the
catalog version, as we don't want to do that at this stage of the  cycle,
and  the changes are very unlikely to affect anyone.
pg_test_fsync: Update output format

Apparently, computers are now a bit faster than when this was first
added, so we need to make room for a digit or two in the ops/sec format.

While we're at it, adjust some of the other output for a more consistent
line length.
Flush unlogged table's buffers when copying or moving databases.

CREATE DATABASE and ALTER DATABASE .. SET TABLESPACE copy the source
database directory on the filesystem level. To ensure the on disk
state is consistent they block out users of the affected database and
force a checkpoint to flush out all data to disk. Unfortunately, up to
now, that checkpoint didn't flush out dirty buffers from unlogged
relations.

That bug means there could be leftover dirty buffers in either the
template database, or the database in its old location. Leading to
problems when accessing relations in an inconsistent state; and to
possible problems during shutdown in the SET TABLESPACE case because
buffers belonging files that don't exist anymore are flushed.

This was reported in bug #10675 by Maxim Boguk.

Fix by Pavan Deolasee, modified somewhat by me. Reviewed by MauMau and
Fujii Masao.

Backpatch to 9.1 where unlogged tables were introduced.
Renumber CHECKPOINT_* flags.

Commit 7dbb6069382 added a new CHECKPOINT_FLUSH_ALL flag. As that
commit needed to be backpatched I didn't change the numeric values of
the existing flags as that could lead to nastly problems if any
external code issued checkpoints. That's not a concern on master, so
renumber them there.

Also add a comment about CHECKPOINT_FLUSH_ALL above
CreateCheckPoint().
Don't duplicate log_checkpoint messages for both of restart and checkpoints.

The duplication originated in cdd46c765, where restartpoints were
introduced.

In LogCheckpointStart's case the duplication actually lead to the
compiler's format string checking not to be effective because the
format string wasn't constant.

Arguably these messages shouldn't be elog(), but ereport() style
messages. That'd even allow to translate the messages... But as
there's more mistakes of that kind in surrounding code, it seems
better to change that separately.
doc: Update FreeBSD documentation tools information

based on patch from Dag-Erling Smørgrav <des@des.no>
doc: Update Red Hat documentation tools information

The old text was written in ancient times when RPM packages could be
shared more or less freely across a plethora of RPM-based Linux
distributions.  This isn't really the case anymore, so just make this
information more concrete for the Red Hat family.
doc: Check DocBook XML validity during the build

Building the documentation with XSLT does not check the DTD, like a
DSSSL build would.  One can often get away with having invalid XML, but
the stylesheets might then create incorrect output, as they are not
designed to handle that.  Therefore, check the validity of the XML
against the DTD, using xmllint, during the build.

Add xmllint detection to configure, and add some documentation.

xmllint comes with libxml2, which is already in use, but it might be in
a separate package, such as libxml2-utils on Debian.

Reviewed-by: Fabien COELHO <coelho@cri.ensmp.fr>
Allow input format xxxx-xxxx-xxxx for macaddr type

Author: Herwin Weststrate <herwin@quarantainenet.nl>
Reviewed-by: Ali Akbar <the.apaan@gmail.com>
Update expected/sequence_1.out.

The last three updates to the sequence regression test have all forgotten
to touch the alternate expected-output file.  Sigh.

Michael Paquier
MinGW: Link with shell32.dll instead of shfolder.dll.

This improves consistency with the MSVC build.  On buildfarm member
narwhal, since commit 846e91e0223cf9f2821c3ad4dfffffbb929cb027,
shfolder.dll:SHGetFolderPath() crashes when dblink calls it by way of
pqGetHomeDirectory().  Back-patch to 9.4, where that commit first
appeared.  How it caused this regression remains a mystery.  This is a
partial revert of commit 889f03812916b146ae504c0fad5afdc7bf2e8a2a, which
adopted shfolder.dll for Windows NT 4.0 compatibility.  PostgreSQL 8.2
dropped support for that operating system.
MinGW: Use -static-libgcc when linking a DLL.

When commit 846e91e0223cf9f2821c3ad4dfffffbb929cb027 switched the linker
driver from dlltool/dllwrap to gcc, it became possible for linking to
choose shared libgcc.  Backends having loaded a module dynamically
linked to libgcc can exit abnormally, which the postmaster treats like a
crash.  Resume use of static libgcc exclusively, like 9.3 and earlier.
Back-patch to 9.4.
Update comment.

The _bt_tuplecompare() function mentioned in comment hasn't existed for a
long time.

Peter Geoghegan
Small code cleanup.

Declare static variable as static and external as extern.
Ensure libpq reports a suitable error message on unexpected socket EOF.

The EOF-detection logic in pqReadData was a bit confused about who should
set up the error message in case the kernel gives us read-ready-but-no-data
rather than ECONNRESET or some other explicit error condition.  Since the
whole point of this situation is that the lower-level functions don't know
there's anything wrong, pqReadData itself must set up the message.  But
keep the assumption that if an errno was reported, a message was set up at
lower levels.

Per bug #11712 from Marko Tiikkaja.  It's been like this for a very long
time, so back-patch to all supported branches.
Add tests for sequence privileges
Minimize calls of pg_class_aclcheck to minimum necessary

In a couple of code paths, pg_class_aclcheck is called in succession
with multiple different modes set.  This patch combines those modes to
have a single call of this function and reduce a bit process overhead
for permission checking.

Author: Michael Paquier <michael@otacoo.com>
Reviewed-by: Fabrízio de Royes Mello <fabriziomello@gmail.com>
Prevent the already-archived WAL file from being archived again.

Previously the archive recovery always created .ready file for
the last WAL file of the old timeline at the end of recovery even when
it's restored from the archive and has .done file. That is, there was
the case where the WAL file had both .ready and .done files.
This caused the already-archived WAL file to be archived again.

This commit prevents the archive recovery from creating .ready file
for the last WAL file if it has .done file, in order to prevent it from
being archived again.

This bug was added when cascading replication feature was introduced,
i.e., the commit 5286105800c7d5902f98f32e11b209c471c0c69c.
So, back-patch to 9.2, where cascading replication was added.

Reviewed by Michael Paquier
Add a function to get the authenticated user ID.

Previously, this was not exposed outside of miscinit.c.  It is needed
for the pending pg_background patch, and will also be needed for
parallelism.  Without it, there's no way for a background worker to
re-create the exact authentication environment that was present in the
process that started it, which could lead to security exposures.
Remove the unused argument of PSQLexec().

This commit simply removes the second argument of PSQLexec that was
set to the same value everywhere. Comments and code blocks related
to this parameter are removed.

Noticed by Heikki Linnakangas, reviewed by Michael Paquier