Rather than waiting around for statement_timeout to expire, we can just
try to take the table's lock in nowait mode.  This saves some fraction
under 4 seconds when running this test with prepared xacts available,
and it guards against timeout-expired-anyway failures on very slow
machines when prepared xacts are not available, as seen in a recent
failure on axolotl for instance.

This approach could fail if autovacuum were to take an exclusive lock
on the test table concurrently, but there's no reason for it to do so.

Since the main point here is to improve stability in the buildfarm,
back-patch to all supported branches.

Patch by Masahiko Sawada

The problem was that "begin transaction" was issued automatically
before executing COMMIT/ROLLBACK PREPARED if not in auto commit. This fix by
Masahiko Sawada fixes this.

Some compilers require it. At least Visual Studio, according to the
buildfarm, and gcc with the -pedantic flag.

From: David Rowley <david.rowley@2ndquadrant.com>

Replace the mapping tables used to convert between UTF-8 and other
character encodings with new radix tree-based maps. Looking up an entry in
a radix tree is much faster than a binary search in the old maps. As a
bonus, the radix tree representation is also more compact, making the
binaries slightly smaller.

The "combined" maps work the same as before, with binary search. They are
much smaller than the main tables, so it doesn't matter so much. However,
the "combined" maps are now stored in the same .map files as the main
tables. This seems more clear, since they're always used together, and
generated from the same source files.

Patch by Kyotaro Horiguchi, with lot of hacking by me at various stages.
Reviewed by Michael Paquier and Daniel Gustafsson.

Discussion: https://www.postgresql.org/message-id/20170306.171609.204324917.horiguchi.kyotaro%40lab.ntt.co.jp

We don't use those files anymore, since commit 1de9cc0d.

Masahiko Sawada

This makes almost all core code follow the policy introduced in the
previous commit.  Specific decisions:

- Text search support functions with char* and length arguments, such as
  prsstart and lexize, may receive unaligned strings.  I doubt
  maintainers of non-core text search code will notice.

- Use plain VARDATA() on values detoasted or synthesized earlier in the
  same function.  Use VARDATA_ANY() on varlenas sourced outside the
  function, even if they happen to always have four-byte headers.  As an
  exception, retain the universal practice of using VARDATA() on return
  values of SendFunctionCall().

- Retain PG_GETARG_BYTEA_P() in pageinspect.  (Page images are too large
  for a one-byte header, so this misses no optimization.)  Sites that do
  not call get_page_from_raw() typically need the four-byte alignment.

- For now, do not change btree_gist.  Its use of four-byte headers in
  memory is partly entangled with storage of 4-byte headers inside
  GBT_VARKEY, on disk.

- For now, do not change gtrgm_consistent() or gtrgm_distance().  They
  incorporate the varlena header into a cache, and there are multiple
  credible implementation strategies to consider.

When commit 3e23b68d introduced
single-byte varlena headers, its fmgr.h changes presented
PG_GETARG_TEXT_PP() and PG_GETARG_TEXT_P() as equals.  Its postgres.h
changes presented PG_DETOAST_DATUM_PACKED() and VARDATA_ANY() as the
exceptional case.  Now, instead, firmly recommend PG_GETARG_TEXT_PP()
over PG_GETARG_TEXT_P(); likewise for other ...PP() macros.  This shaves
cycles and invites consistency of style.

Detect fclose() failures; given "ln -s /dev/full $PGDATA/devfull",
"pg_file_write('devfull', 'x', true)" now fails as it should.  Don't
leak a stream when fwrite() fails.  Remove a born-ineffective test that
aimed to skip zero-length writes.  Back-patch to 9.2 (all supported
versions).

In functions that issue a deconstruct_array() call, consistently use
plain VARSIZE()/VARDATA() on the array elements.  Prior practice was
divided between those and VARSIZE_ANY_EXHDR()/VARDATA_ANY().

When commit 3e23b68d introduced
single-byte varlena headers, it rendered this comment incomplete.

This could only matter if the guessed_type variable had a value that wasn't
a member of the PasswordType enum; but just in case, let's be sure that
control falls out to reach the elog(ERROR) at the end of the function.
Per gripe from Coverity.

Noted by Coverity (a rather impressive catch).

Michael Paquier

Coverity noted that the last line of gather_merge_getnext() was
unreachable, since each arm of the preceding "if" ends in a "return".
Drop it as an oversight.  In passing, improve some nearby comments.

Upcoming patches are revamping expression evaluation significantly. It
therefore seems prudent to try to ensure that the coverage of the
existing evaluation code is high.

This commit adds coverage for the cases that can reasonably be
tested. There's still a bunch of unreachable error messages and such,
but otherwise this achieves nearly full regression test coverage (with
the exception of the unused GetAttributeByNum/GetAttributeByName).

Author: Andres Freund
Discussion: https://postgr.es/m/20170310194021.ek4bs4bl2khxkmll@alap3.anarazel.de

When using unnamed connections with dblink, every time a new
connection is made, the old one is leaked. Fix that.

This has been an issue probably since dblink was first committed.
Someone complained almost ten years ago, but apparently I decided
not to pursue it at the time, and neither did anyone else, so it
slipped between the cracks. Now that someone else has complained,
fix in all supported branches.

Discussion: (orig) https://postgr.es/m/flat/F680AB59-6D6F-4026-9599-1BE28880273D%40decibel.org#F680AB59-6D6F-4026-9599-1BE28880273D@decibel.org
Discussion: (new) https://postgr.es/m/flat/0A3221C70F24FB45833433255569204D1F6ADF8C@G01JPEXMBYT05
Reported by: Jim Nasby and Takayuki Tsunakawa

This allows rolling back the effects of some SPI commands without
having to fail the entire PL/Tcl function.

Victor Wagner, reviewed by Pavel Stehule

Discussion: https://postgr.es/m/20170108205750.2dab04a1@wagner.wagner.home

When one of the kernel calls in the socket()/bind()/listen() sequence
fails, include the specific address we're trying to bind to in the log
message.  This greatly eases debugging of network misconfigurations.

Also, after successfully setting up a listen socket, report its address
in the log, to ease verification that the expected addresses were bound.
There was some debate about whether to print this message at LOG level or
only DEBUG1, but the majority of votes were for the former.

Discussion: https://postgr.es/m/9564.1489091245@sss.pgh.pa.us

Dumping a publication with more than one table crashed pg_dump.

patch by Amit Langote <Langote_Amit_f8@lab.ntt.co.jp>, test by me

There's no really good reason why the autovacuum launcher and logical
replication launcher should announce themselves at startup and shutdown
by default.  Users don't care that those processes exist, and it's
inconsistent that those background processes announce themselves while
others don't.  So, reduce those messages from LOG to DEBUG1 level.

I was sorely tempted to reduce the "starting logical replication worker
for subscription ..." message to DEBUG1 as well, but forebore for now.
Those processes might possibly be of direct interest to users, at least
until logical replication is a lot better shaken out than it is today.

Discussion: https://postgr.es/m/19479.1489121003@sss.pgh.pa.us

This reverts commit ccce90b3.  This
optimization is unsafe, at least, of rollbacks and rollbacks to
savepoints, but I'm concerned there may be other problematic cases as
well.  Therefore, I've decided to revert this pending further
investigation.

Previously they were disabled due to performance concerns on 32bit
arm, where 64bit atomics are often implemented via kernel traps.

Author: Roman Shaposhnik
Discussion: http://postgr.es/m/CA+ULb+uErkFuXUCCXWHYvnV5KnAyjGUzzRcPA-M0cgO+Hm4RSA@mail.gmail.com

Commits 89e0bac8 et al replaced newlines with spaces in object names
printed in SQL comments, but we neglected to consider that the same
names are also printed by "pg_restore -l", and a newline would render
the output unparseable by "pg_restore -L".  Apply the same replacement
in "-l" output.  Since "pg_restore -L" doesn't actually examine any
object names, only the dump ID field that starts each line, this is
enough to fix things for its purposes.

The previous fix was treated as a security issue, and we might have
done that here as well, except that the issue was reported publicly
to start with.  Anyway it's hard to see how this could be exploited
for SQL injection; "pg_restore -L" doesn't do much with the file
except parse it for leading integers.

Per bug #14587 from Milos Urbanek.  Back-patch to all supported versions.

Discussion: https://postgr.es/m/20170310155318.1425.30483@wrigleys.postgresql.org

Seven of the eight other relkind codes are lower-case, so it wasn't
consistent for this one to be upper-case.  Fix it while we still can.

Historical notes: the reason for the lone exception, i.e. sequences being
'S', is that 's' was once used for "special" relations.  Also, at one time
the partitioned-tables patch used both 'P' and 'p', but that got changed,
leaving only a surprising choice behind.

This also fixes a couple little bits of technical debt, such as
type_sanity.sql not knowing that 'm' is a legal value for relkind.

Discussion: https://postgr.es/m/27899.1488909319@sss.pgh.pa.us

Commit be37c212 forgot to teach initdb about commenting out the IPv6
replication entry that it caused to exist in pg_hba.conf.sample.
Per buildfarm.

One file was listed under a wrong comment.

For consistency with other code and to avoid wasting some small amount
of memory.

From: Tsunakawa, Takayuki <tsunakawa.takay@jp.fujitsu.com>

Also remove some unused code and the no longer useful dblink.h file.
Reviewed-by: Tsunakawa, Takayuki <tsunakawa.takay@jp.fujitsu.com>

Although it's reasonable to expect that most of these constants will
never change, that does not make it good programming style to hard-code
the value rather than using the RELKIND_FOO macros.

I think I've now gotten all the hard-coded references in C code.
Unfortunately there's no equally convenient way to parameterize
SQL files ...

Discussion: https://postgr.es/m/11145.1488931324@sss.pgh.pa.us

No exclusive lock is taken anymore...

Per buildfarm.  Maybe some of the other xmin variables in snapmgr.h
ought to get this too, but for the moment I'm just interested in
un-breaking the buildfarm.

Oversight in commit 3717dc14.

Although it's reasonable to expect that most of these constants will
never change, that does not make it good programming style to hard-code
the value rather than using the RELKIND_FOO macros.

Discussion: https://postgr.es/m/11145.1488931324@sss.pgh.pa.us

Commit 7666e73a introduced a dependency on filehandles' input_line_number
method, but apparently that's a Perl neologism.  Use $. instead, which
works at least back to Perl 5.10, and hopefully back to 5.8.

Jeff Janes

Discussion: https://postgr.es/m/CAMkU=1wuQW=xVfu-14A4VCvxO0ohkD3m9vk6HOj_dprQoKNAQw@mail.gmail.com