In the generic atomic ops that rely on a loop around a CAS primitive,
there's no need to force the initial read of the "old" value to be atomic.
In the typically-rare case that we get a torn value, that simply means
that the first CAS attempt will fail; but it will update "old" to the
atomically-read value, so the next attempt has a chance of succeeding.
It was already being done that way in pg_atomic_exchange_u64_impl(),
but let's duplicate the approach in the rest.

(Given the current coding of the pg_atomic_read functions, this change
is a no-op anyway on popular platforms; it only makes a difference where
pg_atomic_read_u64_impl() is implemented as a CAS.)

In passing, also remove unnecessary take-a-pointer-and-dereference-it
coding in the pg_atomic_read functions.  That seems to have been based
on a misunderstanding of what the C standard requires.  What actually
matters is that the pointer be declared as pointing to volatile, which
it is.

I don't believe this will change the assembly code at all on x86
platforms (even ignoring the likelihood that these implementations
get overridden by others); but it may help on less-mainstream CPUs.

Discussion: https://postgr.es/m/13707.1504718238@sss.pgh.pa.us

recovery_target_time accepts timestamp input, though
does not allow use of special values, e.g. “today”.
Report a useful error message for these cases.

Reported-by: Piotr Stefaniak
Author: Simon Riggs
Discussion: https://postgr.es/m/CANP8+jJdKA+BkkYLWz9zAm16Y0s2ExBv0WfpAwXdTpPfWnA9Bg@mail.gmail.com

Use the same parameter names as in the definition.  Cosmetic fix only.

Tatsuro Yamada

Discussion: https://postgr.es/m/58E711AF.7070305@lab.ntt.co.jp

Saves ~150 lines, costs little.

Fabien Coelho, reviewed by Victor Drobny

Discussion: https://postgr.es/m/alpine.DEB.2.20.1703311958001.14355@lancre

Index columns are referenced by ordinal number rather than name, e.g.
CREATE INDEX coord_idx ON measured (x, y, (z + t));
ALTER INDEX coord_idx ALTER COLUMN 3 SET STATISTICS 1000;

Incompatibility note for release notes:
\d+ for indexes now also displays Stats Target

Authors: Alexander Korotkov, with contribution by Adrien NAYRAT
Review: Adrien NAYRAT, Simon Riggs
Wordsmith: Simon Riggs

In addition to __sync_fetch_and_add, gcc offers __sync_fetch_and_sub,
__sync_fetch_and_and, and __sync_fetch_and_or, which correspond directly
to primitive atomic ops that we want.  Testing shows that in some cases
they generate better code than our generic implementations, so use them.

We've assumed that configure's test for __sync_val_compare_and_swap is
sufficient to allow assuming that __sync_fetch_and_add is available, so
make the same assumption for these functions.  Should that prove to be
wrong, we can add more configure tests.

Yura Sokolov, reviewed by Jesper Pedersen and myself

Discussion: https://postgr.es/m/7f65886daca545067f82bf2b463b218d@postgrespro.ru

The pg_atomic_compare_exchange_xxx functions are defined to update
*expected to whatever they read from the target variable.  Therefore,
there's no need to do additional explicit reads after we've initialized
the "old" variable.  The actual benefit of this is somewhat debatable,
but it seems fairly unlikely to hurt anything, especially since we
will override the generic implementations in most performance-sensitive
cases.

Yura Sokolov, reviewed by Jesper Pedersen and myself

Discussion: https://postgr.es/m/7f65886daca545067f82bf2b463b218d@postgrespro.ru

Whitespace use was inconsistent in the same chapter.

This is not required in SGML, but will be in XML, so this is a step to
prepare for the conversion to XML.  (It is still not required to escape
>, but we did it here in some cases for symmetry.)

Add a command-line option to osx/onsgmls calls to warn about unescaped
occurrences in the future.

Author: Alexander Law <exclusion@gmail.com>
Author: Peter Eisentraut <peter.eisentraut@2ndquadrant.com>

The NAMEDTUPLESTORE patch piggybacked on the infrastructure for
TABLEFUNC/VALUES/CTE RTEs, none of which can ever have dropped columns,
so the possibility was ignored most places.  Fix that, including adding a
specification to parsenodes.h about what it's supposed to look like.

In passing, clean up assorted comments that hadn't been maintained
properly by said patch.

Per bug #14799 from Philippe Beaudoin.  Back-patch to v10.

Discussion: https://postgr.es/m/20170906120005.25630.84360@wrigleys.postgresql.org

Reported-by: mjustin.lists@gmail.com

This command acts somewhat like \g, but instead of executing the query
buffer, it merely prints a description of the columns that the query
result would have.  (Of course, this still requires parsing the query;
if parse analysis fails, you get an error anyway.)  We accomplish this
using an unnamed prepared statement, which should be invisible to psql
users.

Pavel Stehule, reviewed by Fabien Coelho

Discussion: https://postgr.es/m/CAFj8pRBhYVvO34FU=EKb=nAF5t3b++krKt1FneCmR0kuF5m-QA@mail.gmail.com

There's no particular reason to target this module for the first
wholesale application of these macros; but we gotta start somewhere.

Ashutosh Bapat and Jeevan Chalke

Discussion: https://postgr.es/m/CAFjFpRcNr3r=u0ni=7A4GD9NnHQVq+dkFafzqo2rS6zy=dt1eg@mail.gmail.com

It has not been used in a long time, and it doesn't seem safe anyway, so
drop it.
Reviewed-by: Michael Paquier <michael.paquier@gmail.com>
Reviewed-by: Ryan Murphy <ryanfmurphy@gmail.com>

Reviewed-by: Michael Paquier <michael.paquier@gmail.com>
Reviewed-by: Ryan Murphy <ryanfmurphy@gmail.com>

The parenthesized style has only been used in a few modules.  Change
that to use the style that is predominant across the whole tree.
Reviewed-by: Michael Paquier <michael.paquier@gmail.com>
Reviewed-by: Ryan Murphy <ryanfmurphy@gmail.com>

Surely everyone has that by now.
Reviewed-by: Michael Paquier <michael.paquier@gmail.com>
Reviewed-by: Ryan Murphy <ryanfmurphy@gmail.com>

Remnants left behind by a323ede2Reviewed-by: Michael Paquier <michael.paquier@gmail.com>
Reviewed-by: Ryan Murphy <ryanfmurphy@gmail.com>

This moves the data directories from using temporary directories with
randomness in the directory name to a static name, to make it easier to
debug.  The data directory will be retained if tests fail or the test
code dies/exits with failure, and is automatically removed on the next
make check.

If the environment variable PG_TEST_NOCLEAN is defined, the data
directories will be retained regardless of test or exit status.

Author: Daniel Gustafsson <daniel@yesql.se>

This allows the user's environment to set up a psql-specific choice
of pager, in much the same way that we provide PSQL_EDITOR to allow
a psql-specific override of the more widely known EDITOR variable.

Pavel Stehule, reviewed by Thomas Munro

Discussion: https://postgr.es/m/CAFj8pRD3RRk9S1eRbnGm_T6brc3Ss5mohraNzTSJquzx+pmtKA@mail.gmail.com

Throttling for sending a base backup in walsender is broken for the case
where there is a lot of WAL traffic, because the latch used to put the
walsender to sleep is also signalled by regular WAL traffic (and each
signal causes an additional batch of data to be sent); the net effect is
that there is no or little actual throttling.  This is undesirable, so
rewrite the sleep into a loop to achieve the desired effeect.

Author: Jeff Janes, small tweaks by me
Reviewed-by: Antonin Houska
Discussion: https://postgr.es/m/CAMkU=1xH6mde-yL-Eo1TKBGNd0PB1-TMxvrNvqcAkN-qr2E9mw@mail.gmail.com

We already had a psql variable VERSION that shows the verbose form of
psql's own version.  Add VERSION_NAME to show the short form (e.g.,
"11devel") and VERSION_NUM to show the numeric form (e.g., 110000).
Also add SERVER_VERSION_NAME and SERVER_VERSION_NUM to show the short and
numeric forms of the server's version.  (We'd probably add SERVER_VERSION
with the verbose string if it were readily available; but adding another
network round trip to get it seems too expensive.)

The numeric forms, in particular, are expected to be useful for scripting
purposes, now that psql can do conditional tests.

Fabien Coelho, reviewed by Pavel Stehule

Discussion: https://postgr.es/m/alpine.DEB.2.20.1704020917220.4632@lancre

The previous format with variable names and descriptions in separate
columns was extremely constraining about the length of the descriptions.
We'd dealt with that in several inconsistent ways over the years,
including letting the lines run over 80 characters, breaking descriptions
into multiple lines, or shoving the description onto a separate line.
But it's been a long time since the output could realistically fit onto
a single screen vertically, so let's just rely even more heavily on the
pager to deal with the vertical distance, and split each entry into two
(or more) lines, in the format

  variable-name
    variable description goes here

Each variable name + description remains a single translatable string,
in hopes of reducing translator confusion; we're just changing the
embedded whitespace.

I failed to resist the temptation to copy-edit one or two of the
descriptions while at it.

Discussion: https://postgr.es/m/2947.1504542679@sss.pgh.pa.us

process_backslash_command would drop the last character of the input
command on the assumption that it was a newline.  Given a non newline
terminated input file, this could result in dropping the last character
of the command.  Fix that by doing an actual test that we're removing
a newline.

While at it, allow for Windows newlines (\r\n), and suppress multiple
newlines if any.  I do not think either of those cases really occur,
since (a) we read script files in text mode and (b) the lexer stops
when it hits a newline.  But it's cheap enough and it provides a
stronger guarantee about what the result string looks like.

This is just cosmetic, I think, since the possibly-overly-chomped
line was only used for display not for further processing.  So
it doesn't seem necessary to back-patch.

Fabien Coelho, reviewed by Nikolay Shaplov, whacked around a bit by me

Discussion: https://postgr.es/m/alpine.DEB.2.20.1704171422500.4025@lancre

With --latency-limit, transactions might get skipped even beyond the
transaction count limit specified by -t, throwing off the expected
number of transactions and thus the denominator for later stats.
Be sure to stop skipping transactions once -t is reached.

Also, include skipped transactions in the "cnt" fields; this requires
discounting them again in a couple of places, but most places are
better off with this definition.  In particular this is needed to
get correct overall stats for the combination of -R/-L/-t options.
Merge some more processing into processXactStats() to simplify this.

In passing, add a check that --progress-timestamp is specified only
when --progress is.

We might consider back-patching this, but given that it only matters
for a combination of options, and given the lack of field complaints,
consensus seems to be not to bother.

Fabien Coelho, reviewed by Nikolay Shaplov

Discussion: https://postgr.es/m/alpine.DEB.2.20.1704171422500.4025@lancre

This puts it in sync with psql's notion of what is a valid variable name.
Like psql, we document that "non-Latin letters" are allowed, but actually
any non-ASCII character is accepted.

Fabien Coelho

Discussion: https://postgr.es/m/20170405.094548.1184280384967203518.t-ishii@sraoss.co.jp

Discussion: https://postgr.es/m/20170828130545.sdajqlpr37hmmd6a@alvherre.pgsql

Some compilers complain, not unreasonably, about left-shifting an
int32 "1" and then assigning the result to an int64.  In practice
I sure hope that this data structure never gets large enough that
an overflow would actually occur; but let's cast the constant to
the right type to avoid the hazard.

In passing, fix a typo in dshash.h.

Amit Kapila, adjusted as per comment from Thomas Munro.

Discussion: https://postgr.es/m/CAA4eK1+5vfVMYtjK_NX8O3-42yM3o80qdqWnQzGquPrbq6mb+A@mail.gmail.com

In commit 9d6b160d, I tweaked pg_config.h.win32 to use
"#define HAVE_LONG_LONG_INT_64 1" rather than defining it as empty,
for consistency with what happens in an autoconf'd build.
But Solution.pm injects another definition of that macro into
ecpg_config.h, leading to justifiable (though harmless) compiler whining.
Make that one consistent too.  Back-patch, like the previous patch.

Discussion: https://postgr.es/m/CAEepm=1dWsXROuSbRg8PbKLh0S=8Ou-V8sr05DxmJOF5chBxqQ@mail.gmail.com

Author: Alexander Lakhin <exclusion@gmail.com>

Move the responsibility for creating/destroying TupleQueueReaders into
execParallel.c, to avoid duplicative coding in nodeGather.c and
nodeGatherMerge.c.  Also, instead of having DestroyTupleQueueReader do
shm_mq_detach, do it in the caller (which is now only ExecParallelFinish).
This means execParallel.c does both the attaching and detaching of the
tuple-queue-reader shm_mqs, which seems less weird than the previous
arrangement.

These changes also eliminate a vestigial memory leak (of the pei->tqueue
array).  It's now demonstrable that rescans of Gather or GatherMerge don't
leak memory.

Discussion: https://postgr.es/m/8670.1504192177@sss.pgh.pa.us

Add the maxrss field to the getrusage output (log_*_stats).  This was
previously omitted because of portability concerns, but we feel this
might not be a concern anymore.

based on patch by Justin Pryzby <pryzby@telsasoft.com>

This probably doesn't save anything meaningful in terms of
performance, but making the code simpler is a good idea anyway.

Code by Beena Emerson, extracted from a larger patch by Jeevan
Ladhe, slightly adjusted by me.

Discussion: http://postgr.es/m/CAOgcT0ONgwajdtkoq+AuYkdTPY9cLWWLjxt_k4SXue3eieAr+g@mail.gmail.com

Instead of using a cast to force the constant to be the right width,
assume we can plaster on an L, UL, LL, or ULL suffix as appropriate.
The old approach to this is very hoary, dating from before we were
willing to require compilers to have working int64 types.

This fix makes the PG_INT64_MIN, PG_INT64_MAX, and PG_UINT64_MAX
constants safe to use in preprocessor conditions, where a cast
doesn't work.  Other symbolic constants that might be defined using
[U]INT64CONST are likewise safer than before.

Also fix the SIZE_MAX macro to be similarly safe, if we are forced
to provide a definition for that.  The test added in commit 2e70d6b5
happens to do what we want even with the hack "(size_t) -1" definition,
but we could easily get burnt on other tests in future.

Back-patch to all supported branches, like the previous commits.

Discussion: https://postgr.es/m/15883.1504278595@sss.pgh.pa.us

Commit a445cb92 removed the default file
names for server-side CRL and CA files, but left them in the docs with a
small note.  This removes the note and the previous default names to
clarify, as well as changes mentions of the file names to make it
clearer that they are configurable.

Author: Daniel Gustafsson <daniel@yesql.se>
Reviewed-by: Michael Paquier <michael.paquier@gmail.com>

Pre-C99 platforms may lack <stdint.h> and thereby SIZE_MAX.  We have
a couple of places using the hack "(size_t) -1" as a fallback, but
it wasn't universally available; which means the code added in commit
2e70d6b5 fails to compile everywhere.  Move that hack to c.h so that
we can rely on having SIZE_MAX everywhere.

Per discussion, it'd be a good idea to make the macro's value safe
for use in #if-tests, but that will take a bit more work.  This is
just a quick expedient to get the buildfarm green again.

Back-patch to all supported branches, like the previous commit.

Discussion: https://postgr.es/m/15883.1504278595@sss.pgh.pa.us

Michael Paquier, reviewed by Fabien Coelho

Discussion: http://postgr.es/m/CAB7nPqQcYWmrm2n-dVaMUhYPKFU_DxQwPuUGuC4ZF+8B=dS5xQ@mail.gmail.com

Commit 0e141c0f introduced a mechanism
to reduce contention on ProcArrayLock by having a single process clear
XIDs in the procArray on behalf of multiple processes, reducing the
need to hand the lock around.  A previous attempt to introduce a similar
mechanism for CLogControlLock in ccce90b3
crashed and burned, but the design problem which resulted in those
failures is believed to have been corrected in this version.

Amit Kapila, with some cosmetic changes by me.  See the previous commit
message for additional credits.

Discussion: http://postgr.es/m/CAA4eK1KudxzgWhuywY_X=yeSAhJMT4DwCjroV5Ay60xaeB2Eew@mail.gmail.com

The original code had a race condition because it never ensured the
standby was caught up before proceeding; add a wait similar to every
other place that does this.

Author: Michaël Paquier
Discussion: https://postgr.es/m/CAB7nPqTm9p+LCm1mVJYvgpwagRK+uibT-pKq0O2-paOWxT62jw@mail.gmail.com