Since the SPI stack has been moved from TopTransactionContext to
TopMemoryContext, setting _SPI_stack to NULL in AtEOXact_SPI() leaks
memory.  In fact, we don't need to do that anymore: We just leave the
allocated stack around for the next SPI use.

Also, refactor the SPI cleanup so that it is run both at transaction end
and when returning to the main loop on an exception.  The latter is
necessary when a procedure calls a COMMIT or ROLLBACK command that
itself causes an error.

Etsuro Fujita

Discussion: http://postgr.es/m/5AE99BA7.9060001@lab.ntt.co.jp

Instead of depending on glibc's getauxval() function, just try to execute
the CRC code, and trap SIGILL if that happens.

Thomas Munro

Discussion: https://postgr.es/m/HE1PR0801MB1323D171938EABC04FFE7FA9E3110@HE1PR0801MB1323.eurprd08.prod.outlook.com

As in e348e7ae for jsonb/plperl, prevent
putting a NaN into a jsonb numeric field.

Tests for this had been removed in
6278a2a2, but in case they are ever
resurrected: This would change the output of the test1nan() function to
an error.

Perl's XSUB.h header defines macros to replace libc functions.  Our header
port_win32.h does something similar earlier, so XSUB.h causes compiler
warnings about macro redefinition.  Undefine our macros before including
XSUB.h.

Thomas Munro

Discussion: https://postgr.es/m/CAEepm%3D3%3DTDYEXUEcHpEx%2BTwc31wo7PA0oBAiNt6sWmq93MW02A%40mail.gmail.com

Failure to use DatumGetFoo/FooGetDatum macros correctly, or at all,
causes some warnings about sign conversion.  This is just cosmetic
at the moment but in principle it's a type violation, so clean up
the instances I could find.

autoprewarm.c and sharedfileset.c contained code that unportably
assumed that pid_t is the same size as int.  We've variously dealt
with this by casting pid_t to int or to unsigned long for printing
purposes; I went with the latter.

Fix uninitialized-variable warning in RestoreGUCState.  This is
a live bug in some sense, but of no great significance given that
nobody is very likely to care what "line number" is associated with
a GUC that hasn't got a source file recorded.

statext_dependencies_load and statext_ndistinct_load were not up to snuff,
in addition to being randomly different from each other.  In detail:

* Deserialize the fetched bytea value before releasing the syscache
entry, not after.  This mistake causes visible regression test failures
when running with -DCATCACHE_FORCE_RELEASE.  Since it's not exposed by
-DCLOBBER_CACHE_ALWAYS, I think there may be no production hazard here
at present, but it's at least a latent bug.

* Use DatumGetByteaPP not DatumGetByteaP to save a detoasting cycle
for short stats values; the deserialize function has to be, and is,
prepared for short-header values since its other caller uses PP.

* Use a test-and-elog for null stats values in both functions, rather
than a test-and-elog in one case and an Assert in the other.  Perhaps
Asserts would be sufficient in both cases, but I don't see a good
argument for them being different.

* Minor cosmetic changes to make these functions more visibly alike.

Backpatch to v10 where this code came in.

Amit Langote, minor additional hacking by me

Discussion: https://postgr.es/m/1349aabb-3a1f-6675-9fc0-65e2ce7491dd@lab.ntt.co.jp

Amit Langote

Support for version-0 calling convention was removed in PostgreSQL v10.
Change the SPI example to use version 1 convention, so that it actually
works.

Author: John Naylor
Discussion: https://www.postgresql.org/message-id/CAJVSVGVydmhLBdm80Rw3G8Oq5TnA7eCxUv065yoZfNfLbF1tzA@mail.gmail.com

There were three related issues:

* BufFileAppend() incorrectly reset the seek position on the 'source' file.
  As a result, if you had called BufFileRead() on the file before calling
  BufFileAppend(), it got confused, and subsequent calls would read/write
  at wrong position.

* BufFileSize() did not work with files opened with BufFileOpenShared().

* FileGetSize() only worked on temporary files.

To fix, change the way BufFileSize() works so that it works on shared
files. Remove FileGetSize() altogether, as it's no longer needed. Remove
buffilesize from TapeShare struct, as the leader process can simply call
BufFileSize() to get the tape's size, there's no need to pass it through
shared memory anymore.

Discussion: https://www.postgresql.org/message-id/CAH2-WznEDYe_NZXxmnOfsoV54oFkTdMy7YLE2NPBLuttO96vTQ@mail.gmail.com

Commit 41c912ca caused MSVC to complain that not all control paths
return a value.

Thomas Munro

Discussion: https://postgr.es/m/CAEepm%3D3%3DTDYEXUEcHpEx%2BTwc31wo7PA0oBAiNt6sWmq93MW02A%40mail.gmail.com

For some reason it was previously defined as 0, which is silly.  The only
effect was to disable use of <stdbool.h>, which commit b2328bf6 intended
to make possible.

Thomas Munro

Discussion: https://postgr.es/m/CAEepm%3D3%3DTDYEXUEcHpEx%2BTwc31wo7PA0oBAiNt6sWmq93MW02A%40mail.gmail.com

Tom's earlier commit in 41c912ca didn't update a few cases that
are only encountered with the non-standard --with-llvm config
flag. Additionally there's also one case that appears to be a
deficiency in gcc's (up to trunk as of a few days ago) detection of
"fallthrough" comments - changing the placement slightly fixes that.

Author: Andres Freund
Discussion: https://postgr.es/m/20180502003239.wfnqu7ekz7j7imm4@alap3.anarazel.de

Don't overflow the result type of constant expressions.  Don't negate
unsigned types.  Define HAVE_STDBOOL_H for Visual C++ 2013 and later.

Thomas Munro
Reviewed-By: Michael Paquier and Tom Lane

Discussion: https://postgr.es/m/CAEepm%3D3%3DTDYEXUEcHpEx%2BTwc31wo7PA0oBAiNt6sWmq93MW02A%40mail.gmail.com

Recent gcc can warn about switch-case fall throughs that are not
explicitly labeled as intentional.  This seems like a good thing,
so clean up the warnings exposed thereby by labeling all such
cases with comments that gcc will recognize.

In files that already had one or more suitable comments, I generally
matched the existing style of those.  Otherwise I went with
/* FALLTHROUGH */, which is one of the spellings approved at the
more-restrictive-than-default level -Wimplicit-fallthrough=4.
(At the default level you can also spell it /* FALL ?THRU */,
and it's not picky about case.  What you can't do is include
additional text in the same comment, so some existing comments
containing versions of this aren't good enough.)

Testing with gcc 8.0.1 (Fedora 28's current version), I found that
I also had to put explicit "break"s after elog(ERROR) or ereport(ERROR);
apparently, for this purpose gcc doesn't recognize that those don't
return.  That seems like possibly a gcc bug, but it's fine because
in most places we did that anyway; so this amounts to a visit from the
style police.

Discussion: https://postgr.es/m/15083.1525207729@sss.pgh.pa.us

Previously a tuple that has been moved to a different partition (see
f16241be), set the block number on the old tuple to an invalid
value to indicate that fact. But the tuple offset was left
untouched. That turned out to trigger a wal_consistency_checking
failure as reported by Peter Geoghegan, as the offset wasn't
always overwritten during WAL replay.

Heikki observed that we're wasting valuable data by not putting
information also in the offset. Thus set that to
MovedPartitionsOffsetNumber when a tuple indicates it has moved.

We continue to set the block number to MovedPartitionsBlockNumber, as
that seems more likely to cause problems for code not updated to know
about moved tuples.

As t_ctid's offset number is now always set, this refinement also
fixes the wal_consistency_checking issue.

This technically is a minor disk format break, with previously created
moved tuples not being recognized anymore. But since there not even
has been a beta release since f16241be...

Reported-By: Peter Geoghegan
Author: Heikki Linnakangas, Amul Sul
Discussion: https://postgr.es/m/CAH2-Wzm9ty+1BX7-GMNJ=xPRg67oJTVeDNdA9LSyJJtMgRiCMA@mail.gmail.com

Without these fixes, changes to the inserted tuple made by remote
triggers are ignored when building local RETURNING tuples.

In the core code, call ExecInitRoutingInfo at a later point from
within ExecInitPartitionInfo so that the FDW callback gets invoked
after the returning list has been built.  But move CheckValidResultRel
out of ExecInitRoutingInfo so that it can happen at an earlier stage.

In postgres_fdw, refactor assorted deparsing functions to work with
the RTE rather than the PlannerInfo, which saves us having to
construct a fake PlannerInfo in cases where we don't have a real one.
Then, we can pass down a constructed RTE that yields the correct
deparse result when no real one exists.  Unfortunately, this
necessitates a hack that understands how the core code manages RT
indexes for update tuple routing, which is ugly, but we don't have a
better idea right now.

Original report, analysis, and patch by Etsuro Fujita.  Heavily
refactored by me.  Then worked over some more by Amit Langote.

Discussion: http://postgr.es/m/5AD4882B.10002@lab.ntt.co.jp

It turns out that old Perl versions (before about 5.10) don't have any
very reliable way to generate Inf or NaN numeric values.  Getting around
that would require way more work than is really justified to test the
code involved, so let's just drop these new test cases.

Discussion: https://postgr.es/m/28585.1525131438@sss.pgh.pa.us

Revert commits 23078689, 73042b8d, ce07aff4, f7df8043, 6ba0cc4b,
eb16011f, 68e7e973, 63ca350e.  We still have a problem here, but
somebody who's actually a Windows developer will need to spend time
on it.

Discussion: https://postgr.es/m/25495.1524517820@sss.pgh.pa.us

Back branches still are SGML.

David Rowley, Amit Langote

The previous coding here didn't actually produce Inf or NaN double
values in Perl versions 5.8.x.  Adopt a suggestion from stackoverflow.

Discussion: https://postgr.es/m/28585.1525131438@sss.pgh.pa.us

Revert the map/unmap dance I tried in commit 73042b8d; that helps
not at all.

Instead, speculate that the unwanted allocation is being done on
another thread, and thus timing variations explain the apparent
unpredictability.  Temporarily add a 1-second sleep before the
VirtualFree call, in hopes that any such other threads will
quiesce and not jog our elbow.

This is obviously not a desirable long-term fix, but as a means of
investigation it seems useful.

Discussion: https://postgr.es/m/25495.1524517820@sss.pgh.pa.us

The idea here is to get Windows' userspace infrastructure to allocate
whatever space it needs for MapViewOfFileEx() before we release the
locked-down space that we want to map the shared memory block into.

This is a fairly brute-force attempt, and would likely (for example)
fail with large shared memory on 32-bit Windows.  We could perhaps
ameliorate that by mapping only part of the shared memory block in
this way, but for the moment I just want to see if this approach
will fix dory's problem.

Discussion: https://postgr.es/m/25495.1524517820@sss.pgh.pa.us

Rather than elog'ing immediately, push the map data into a preallocated
StringInfo.  Perhaps this will prevent some of the mid-operation
allocations that are evidently happening now.

Discussion: https://postgr.es/m/25495.1524517820@sss.pgh.pa.us

The code previously undefined isnan because of a compiler warning on
MinGW.  Since we now need to use isnan, we can't do that anymore.

We might need a different solution if the compiler warning is too
annoying.

So by default, they don't output anything if everything is well.

Discussion: https://www.postgresql.org/message-id/867f8a1a-6cf0-d835-78d8-0844e4936241%402ndquadrant.com

When due to publication configuration, a TRUNCATE change ends up with
zero tables to be published, don't send the message out, just skip it.
It's not wrong, but obviously useless overhead.

jsonb uses numeric internally, and numeric can store NaN, but that is
not allowed by jsonb on input, so we shouldn't store it.  Also prevent
infinity to get a consistent error message.  (numeric input would reject
infinity anyway.)
Reported-by: Dagfinn Ilmari Mannsåker <ilmari@ilmari.org>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>

This code is evidently allocating memory and thus confusing matters
even more.  Let's see whether we can learn anything with
just VirtualQuery.

Discussion: https://postgr.es/m/25495.1524517820@sss.pgh.pa.us

This morning's results from buildfarm member dory make it pretty
clear that something is getting mapped into the just-freed space,
but not what that something is.  Replace my minimalistic probes
with a full dump of the process address space and module space,
based on Noah's work at
<20170403065106.GA2624300%40tornado.leadboat.com>

This is all (probably) to get reverted once we have fixed the
problem, but for now we need information.

Discussion: https://postgr.es/m/25495.1524517820@sss.pgh.pa.us

While looking at a recent buildfarm failure in the ecpg tests, I wondered
why the pg_regress output claimed the stderr part of the test failed, when
the regression diffs were clearly for the stdout part.  Looking into it,
the reason is that pg_regress.c's logic for iterating over three parallel
lists is wrong, and has been wrong since it was written: it advances the
"tag" pointer at a different place in the loop than the other two pointers.
Fix that.

After some thought about the info captured so far, it seems possible
that MapViewOfFileEx is itself causing some DLL to get loaded into
the space just freed by VirtualFree.  The previous commit here didn't
capture enough info to really prove the case for that, so let's add
one more VirtualQuery in between those steps.  Also, be sure to
capture the post-Map state before we emit any log entries, just in
case elog() is invoking some code not previously loaded.

Discussion: https://postgr.es/m/25495.1524517820@sss.pgh.pa.us

Buildfarm results show that the modern POSIX rule that 1 ^ NaN = 1 is not
honored on *BSD until relatively recently, and really old platforms don't
believe that NaN ^ 0 = 1 either.  (This is unsurprising, perhaps, since
SUSv2 doesn't require either behavior.)  In hopes of getting to platform
independent behavior, let's deal with all the NaN-input cases explicitly
in dpow().

Note that numeric_power() doesn't know either of these special cases.
But since that behavior is platform-independent, I think it should be
addressed separately, and probably not back-patched.

Discussion: https://postgr.es/m/75DB81BEEA95B445AE6D576A0A5C9E936A73E741@BPXM05GP.gisp.nec.co.jp