While at it also update the comments in walmethods.h to make it less
likely for mistakes like this to appear in the future (thanks to Tom for
improvements to the comments).

And finally, in passing change the return type of walmethod.getlasterror
to being const, also per suggestion from Tom.

Commit a4777f35 was a shade too mechanical: we don't want to override
MSVC's own definition of _MSC_VER, as that breaks tests on its numerical
value.  Per buildfarm.

Commit 0bf3ae88 encountered a need to pass the finally chosen remote qual
conditions forward from postgresGetForeignPlan to postgresPlanDirectModify.
It solved that by sticking them into the plan node's fdw_private list,
which in hindsight was a pretty bad idea.  In the first place, there's no
use for those qual trees either in EXPLAIN or execution; indeed they could
never safely be used for any post-planning purposes, because they would not
get processed by setrefs.c.  So they're just dead weight to carry around in
the finished plan tree, plus being an attractive nuisance for somebody who
might get the idea that they could be used that way.  Secondly, because
those qual trees (sometimes) contained RestrictInfos, they created a
plan-transmission hazard for parallel query, which is how come we noticed a
problem.  We dealt with that symptom in commit 28b04787, but really a more
straightforward and more efficient fix is to pass the data through in a new
field of struct PgFdwRelationInfo.  So do it that way.  (There's no need
to revert 28b04787, as it has sufficient reason to live anyway.)

Per fuzz testing by Andreas Seltenreich.

Discussion: https://postgr.es/m/87tw5x4vcu.fsf@credativ.de

Commit f0e44751 should have updated
this code, but did not.

Amit Langote

Discussion: http://postgr.es/m/52d9c443-ec78-5c8a-7a77-0f34aad12b82@lab.ntt.co.jp

To prevent future bugs along the lines of the one corrected by commit
8ff51869, or find any that remain
in the current code, add an Assert() that the difference between
parallel_register_count and parallel_terminate_count is in a sane
range.

Kuntal Ghosh, with considerable tidying-up by me, per a suggestion
from Neha Khatri.  Reviewed by Tomas Vondra.

Discussion: http://postgr.es/m/CAFO0U+-E8yzchwVnvn5BeRDPgX2z9vZUxQ8dxx9c0XFGBC7N1Q@mail.gmail.com

Commit b460f5d6 failed to contemplate
the possibilit that a parallel worker registered before a crash would
be unregistered only after the crash; if that happened, we'd end up
with parallel_terminate_count > parallel_register_count and the
system would refuse to launch any more parallel workers.

The easiest way to fix that seems to be to forget BGW_NEVER_RESTART
workers in ResetBackgroundWorkerCrashTimes() rather than leaving them
around to be cleaned up after the conclusion of the restart, so that
they go away before rather than after shared memory is reset.

To make sure that this fix is water-tight, don't allow parallel
workers to be anything other than BGW_NEVER_RESTART, so that after
recovering from a crash, 0 is guaranteed to be the correct starting
value for parallel_register_count.  The core code wouldn't do this
anyway, but somebody might try to do it in extension code.

Report by Thomas Vondra.  Patch by me, reviewed by Kuntal Ghosh.

Discussion: http://postgr.es/m/CAGz5QC+AVEVS+3rBKRq83AxkJLMZ1peMt4nnrQwczxOrmo3CNw@mail.gmail.com

Reported-by: Marek <marek.cvoren@gmail.com>

Discussion: 20170328110253.2695.62609@wrigleys.postgresql.org

Commit 98e6e890 made inadequate
provision for the case of a single-page shared tidbitmap.  It
allocate space for a shared PagetableEntry, but failed to
initialize it.

Report by Thomas Munro.  Patch by Dilip Kumar, with some comment
changes by me.

Discussion: http://postgr.es/m/CAEepm=19Cmnfbi-j2Bw-a6yGPeHE1OVhKvvKz9bRBTJGKfGHMA@mail.gmail.com

Clauses in the lists retained by postgres_fdw during planning were
sometimes bare boolean clauses, sometimes RestrictInfos, and sometimes
a mixture of the two in the same list.  The comment about that situation
didn't come close to telling the full truth, either.  Aside from being
confusing, this had a couple of bad practical consequences:
* waste of planning cycles due to inability to cache per-clause selectivity
and cost estimates;
* sometimes, RestrictInfos would sneak into the fdw_private list of a
finished Plan node, causing failures if, for example, we tried to ship
the Plan tree to a parallel worker.
(It may well be that it's a bug in the parallel-query logic that we
would ever try to ship such a plan to a parallel worker, but in any
case this deserves to be cleaned up.)

To fix, rearrange so that clause lists in PgFdwRelationInfo are always
lists of RestrictInfos, and then strip the RestrictInfos at the last
minute when making a Plan node.  In passing do a bit of refactoring and
comment cleanup in postgresGetForeignPlan and foreign_join_ok.

Although the messiness here dates back at least to 9.6, there's no evidence
that it causes anything worse than wasted planning cycles in 9.6, so no
back-patch for now.

Per fuzz testing by Andreas Seltenreich.

Tom Lane and Ashutosh Bapat

Discussion: https://postgr.es/m/87tw5x4vcu.fsf@credativ.de

This commit also does

- add REPLICATION_SUBSCRIBERS into config_group
- mark max_logical_replication_workers and max_sync_workers_per_subscription
  as REPLICATION_SUBSCRIBERS parameters
- move those parameters into "Subscribers" section in postgresql.conf.sample

Author: Masahiko Sawada, Petr Jelinek and me
Reported-by: Masahiko Sawada
Discussion: http://postgr.es/m/CAD21AoAonSCoa=v=87ZO3vhfUZA1k_E2XRNHTt=xioWGUa+0ug@mail.gmail.com

Specifically, the behavior of general-purpose and statistical aggregates
as window functions was not clearly documented, and terms were
inconsistently used.  Also add docs about the difference between
cume_dist and percent_rank, rather than just the formulas.

Discussion: 20170406214918.GA5757@momjian.us

This used to mean "Visual C++ except in those parts where Borland C++
was supported where it meant one of those". Now that we don't support
Borland C++ anymore, simplify by using _MSC_VER which is the normal way
to detect Visual C++.

This removes the support for building just libpq using Borland C++ or
Visual C++. This has not worked properly for years, and given the number
of complaints it's clearly not worth the maintenance burden.

Building libpq using the standard MSVC build system is of course still
supported, along with mingw.

heap_drop_with_catalog and RangeVarCallbackForDropRelation should
lock the parent before locking the target relation.

Amit Langote

Discussion: http://postgr.es/m/29588799-a8ce-b0a2-3dae-f39ff6d35922@lab.ntt.co.jp

As a consequence of commit 1d63f7d2, on platforms with CLOCK_MONOTONIC,
you got some random timescale or other instead of standard Unix timestamps
as expected.  I'd attempted to fix pgbench for that change in commits
74baa1e3 and 67a87535, but missed this place.  Fix in the same way as
those previous commits, ie, just eat the cost of an extra gettimeofday();
one extra syscall per progress report isn't worth sweating over.  Per
report from Jeff Janes.

In passing, use snprintf not sprintf for this purpose.  I don't think
there's any chance of actual buffer overrun, but it just looks safer.

Discussion: https://postgr.es/m/CAMkU=1zrQaPwBN+NcBd3pWCb=vWaiL=mmWfJjDJjh-a7eVr-Og@mail.gmail.com

Patch by Kato, Sho <kato-sho@jp.fujitsu.com>

Commit 96a7128b made pg_dump and pg_dumpall sync their output by
default. However, there's no great need for that in testing, and it
could impose a performance penalty, so we add the --no-sync flag to most
of the test cases.

Michael Paquier

The previously used ShareRowExclusiveLock, while technically probably
more correct, led to deadlocks during seemingly unrelated operations and
thus a poor experience.  Use RowExclusiveLock, like for most similar
catalog operations.  In some care cases, the user might see an error
from DDL commands.

Discussion: https://www.postgresql.org/message-id/flat/13592.1490851519%40sss.pgh.pa.us

Author: Petr Jelinek <petr.jelinek@2ndquadrant.com>

The backend local copy of dsa_area_control->freed_segment_counter was
not properly initialized / maintained.  This could, if unlucky, lead
to keeping attached to a segment for too long.

Found via valgrind bleat on buildfarm animal skink.

Author: Thomas Munro
Discussion: https://postgr.es/m/20170407164935.obsf2jipjfos5zei@alap3.anarazel.de

This extends the castNode() notation introduced by commit 5bcab111 to
provide, in one step, extraction of a list cell's pointer and coercion to
a concrete node type.  For example, "lfirst_node(Foo, lc)" is the same
as "castNode(Foo, lfirst(lc))".  Almost half of the uses of castNode
that have appeared so far include a list extraction call, so this is
pretty widely useful, and it saves a few more keystrokes compared to the
old way.

As with the previous patch, back-patch the addition of these macros to
pg_list.h, so that the notation will be available when back-patching.

Patch by me, after an idea of Andrew Gierth's.

Discussion: https://postgr.es/m/14197.1491841216@sss.pgh.pa.us

Author: Michael Paquier <michael.paquier@gmail.com>
Reviewed-by: Petr Jelinek <petr.jelinek@2ndquadrant.com>
Reported-by: Fujii Masao <masao.fujii@gmail.com>

We decided in f1b4c771 to pass the
original slot to ExecConstraints(), but that breaks when there are
BEFORE ROW triggers involved.  So we need to do reverse-map the tuples
back to the original descriptor instead, as Amit originally proposed.

Amit Langote, reviewed by Ashutosh Bapat.  One overlooked comment
fixed by me.

Discussion: http://postgr.es/m/b3a17254-6849-e542-2353-bde4e880b6a4@lab.ntt.co.jp

Commit 4deb4138 modified isolationtester's query to see whether a
session is blocked to also check for waits occurring in GetSafeSnapshot.
However, it did that in a way that enormously increased the query's
runtime under CLOBBER_CACHE_ALWAYS, causing the buildfarm members
that use that to run about four times slower than before, and in some
cases fail entirely.  To fix, push the entire logic into a dedicated
backend function.  This should actually reduce the CLOBBER_CACHE_ALWAYS
runtime from what it was previously, though I've not checked that.

In passing, expose a SQL function to check for safe-snapshot blockage,
comparable to pg_blocking_pids.  This is more or less free given the
infrastructure built to solve the other problem, so we might as well.

Thomas Munro

Discussion: https://postgr.es/m/20170407165749.pstcakbc637opkax@alap3.anarazel.de

Oops, I forgot to "git add" this to previous commit.

It is documented in the Streaming Replication Protocol section, but was
missing from the list of options in StartupMessage description.

In commit 25542d77, regression test coverage was added to sepgsql
for partitioned tables. Unfortunately it was not robust in the face
of collation differences, per the buildfarm. Force "C" collation
in order to fix that.

Discussion: https://postgr.es/m/flat/623bcaae-112e-ced0-8c22-a84f75ae0c53%40joeconway.com

The new partitioned table capability added a new relkind, namely
RELKIND_PARTITIONED_TABLE. Update sepgsql to treat this new relkind
exactly the same way it does RELKIND_RELATION.

In addition, add regression test coverage for partitioned tables.

Issue raised by Stephen Frost and initial patch by Mike Palmiotto.
Review by Tom Lane and Robert Haas, and editorializing by me.

Discussion: https://postgr.es/m/flat/623bcaae-112e-ced0-8c22-a84f75ae0c53%40joeconway.com

Commit ac2b0950 was not terribly carefully reviewed.  Band-aid it to
not fail on non-RestrictInfo input, per report from Andreas Seltenreich.
Also make it do something more reasonable with variable-free clauses,
and improve nearby comments.

Discussion: https://postgr.es/m/87inmf5rdx.fsf@credativ.de

Oversight in 60f11b87.

Fix by forcing database encoding to UTF-8, regardless of the current
locale.

Pointed out by Tom Lane.

Discussion: https://www.postgresql.org/message-id/8934.1491614631@sss.pgh.pa.us

Defaults match the fixed behavior of prior releases, but now DBAs
have better options to tune serializable workloads.

It might be nice to be able to set this per relation, but that part
will need to wait for another release.

Author: Dagfinn Ilmari Mannsåker

If there can certainly be no more than one matching inner row for a given
outer row, then the executor can move on to the next outer row as soon as
it's found one match; there's no need to continue scanning the inner
relation for this outer row.  This saves useless scanning in nestloop
and hash joins.  In merge joins, it offers the opportunity to skip
mark/restore processing, because we know we have not advanced past the
first possible match for the next outer row.

Of course, the devil is in the details: the proof of uniqueness must
depend only on joinquals (not otherquals), and if we want to skip
mergejoin mark/restore then it must depend only on merge clauses.
To avoid adding more planning overhead than absolutely necessary,
the present patch errs in the conservative direction: there are cases
where inner_unique or skip_mark_restore processing could be used, but
it will not do so because it's not sure that the uniqueness proof
depended only on "safe" clauses.  This could be improved later.

David Rowley, reviewed and rather heavily editorialized on by me

Discussion: https://postgr.es/m/CAApHDvqF6Sw-TK98bW48TdtFJ+3a7D2mFyZ7++=D-RyPsL76gw@mail.gmail.com

When the 64bit atomics simulation is in use, we can't necessarily
guarantee the correct alignment of the atomics due to lack of compiler
support for doing so- that's fine from a safety perspective, because
everything is protected by a lock, but we asserted the alignment in
all cases.  Weaken them.  Per complaint from Alvaro Herrera.

My #ifdefery for PG_HAVE_8BYTE_SINGLE_COPY_ATOMICITY wasn't
sufficient. Fix that.  Per complaint from Alexander Korotkov.

This enables the same OpenSP warnings on osx calls that we get from
onsgmls (make check) and formerly from openjade.

Older tool chains apparently have some of these warnings on by
default (see comment at SPFLAGS assignment).  So users of such tool
chains would complain about warnings or errors that users of newer tool
chains would not see, unless they used "make check".

Author: Erik Rijkers <er@xs4all.nl>

Using %ld as we were doing raises compiler warnings on 32 bit platforms.

Reported by Andres Freund.
Discussion: https://postgr.es/m/20170407214022.fidezl2e6rk3tuiz@alap3.anarazel.de

Instead of allocating memory in brin_deform_tuple and brin_copy_tuple
over and over during a scan, allow reuse of previously allocated memory.
This is said to make for a measurable performance improvement.

Author: Jinyu Zhang, Álvaro Herrera
Reviewed by: Tomas Vondra
Discussion: https://postgr.es/m/495deb78.4186.1500dacaa63.Coremail.beijing_pg@163.com