Add large object functions catering to SQL callers.

With these, one need no longer manipulate large object descriptors and
extract numeric constants from header files in order to read and write
large object contents from SQL.

Pavel Stehule, reviewed by Rushabh Lathia.
Suppress duplicate-index-entry warning introduced by previous commit.

We don't need two index entries for lo_create pointing at the same section.
It's a bit pedantic for the toolchain to warn about this, but warn it does.
Improve documentation about usage of FDW validator functions.

SGML documentation, as well as code comments, failed to note that an FDW's
validator will be applied to foreign-table options for foreign tables using
the FDW.

Etsuro Fujita
Work around NetBSD shell issue in pg_upgrade test script.

The NetBSD shell apparently returns non-zero from an unset command if
the variable is already unset. This matters when, as in pg_upgrade's
test.sh, we are working under 'set -e'. To protect against this, we
first set the PG variables to an empty string before unsetting them
completely.

Error found on buildfarm member coypu, solution from Rémi Zara.
Modify dynamic shared memory code to use Size rather than uint64.

This is more consistent with what we do elsewhere.
Prevent using strncpy with src == dest in TupleDescInitEntry.

The C and POSIX standards state that strncpy's behavior is undefined when
source and destination areas overlap.  While it remains dubious whether any
implementations really misbehave when the pointers are exactly equal, some
platforms are now starting to force the issue by complaining when an
undefined call occurs.  (In particular OS X 10.9 has been seen to dump core
here, though the exact set of circumstances needed to trigger that remain
elusive.  Similar behavior can be expected to be optional on Linux and
other platforms in the near future.)  So tweak the code to explicitly do
nothing when nothing need be done.

Back-patch to all active branches.  In HEAD, this also lets us get rid of
an exception in valgrind.supp.

Per discussion of a report from Matthias Schmitt.
Fix old typo in comment.

NFAs have children, but their individual states don't.
Avoid too-large shift on 32-bit Windows.

Apparently, shifts greater than or equal to the width of the type
are undefined, and can surprisingly produce a non-zero value.

Amit Kapila, with a comment by me.
Use appendStringInfoString instead of appendStringInfo where possible.

This shaves a few cycles, and generally seems like good programming
practice.

David Rowley
Fix some odd behaviors when using a SQL-style simple GMT offset timezone.

Formerly, when using a SQL-spec timezone setting with a fixed GMT offset
(called a "brute force" timezone in the code), the session_timezone
variable was not updated to match the nominal timezone; rather, all code
was expected to ignore session_timezone if HasCTZSet was true.  This is
of course obviously fragile, though a search of the code finds only
timeofday() failing to honor the rule.  A bigger problem was that
DetermineTimeZoneOffset() supposed that if its pg_tz parameter was
pointer-equal to session_timezone, then HasCTZSet should override the
parameter.  This would cause datetime input containing an explicit zone
name to be treated as referencing the brute-force zone instead, if the
zone name happened to match the session timezone that had prevailed
before installing the brute-force zone setting (as reported in bug #8572).
The same malady could affect AT TIME ZONE operators.

To fix, set up session_timezone so that it matches the brute-force zone
specification, which we can do using the POSIX timezone definition syntax
"<abbrev>offset", and get rid of the bogus lookaside check in
DetermineTimeZoneOffset().  Aside from fixing the erroneous behavior in
datetime parsing and AT TIME ZONE, this will cause the timeofday() function
to print its result in the user-requested time zone rather than some
previously-set zone.  It might also affect results in third-party
extensions, if there are any that make use of session_timezone without
considering HasCTZSet, but in all cases the new behavior should be saner
than before.

Back-patch to all supported branches.
Remove internal uses of CTimeZone/HasCTZSet.

The only remaining places where we actually look at CTimeZone/HasCTZSet
are abstime2tm() and timestamp2tm().  Now that session_timezone is always
valid, we can remove these special cases.  The caller-visible impact of
this is that these functions now always return a valid zone abbreviation
if requested, whereas before they'd return a NULL pointer if a brute-force
timezone was in use.  In the existing code, the only place I can find that
changes behavior is to_char(), whose TZ format code will now print
something useful rather than nothing for such zones.  (In the places where
the returned zone abbreviation is passed to EncodeDateTime, the lack of
visible change is because we've chosen the abbreviation used for these
zones to match what EncodeTimezone would have printed.)

It's likely that there is now a fair amount of removable dead code around
the call sites, namely anything that's meant to cope with getting a NULL
timezone abbreviation, but I've not made an effort to root that out.

This could be back-patched if we decide we'd like to fix to_char()'s
behavior in the back branches, but there doesn't seem to be much
enthusiasm for that at present.
Remove CTimeZone/HasCTZSet, root and branch.

These variables no longer have any useful purpose, since there's no reason
to special-case brute force timezones now that we have a valid
session_timezone setting for them.  Remove the variables, and remove the
SET/SHOW TIME ZONE code that deals with them.

The user-visible impact of this is that SHOW TIME ZONE will now show a
POSIX-style zone specification, in the form "<+-offset>-+offset", rather
than an interval value when a brute-force zone has been set.  While perhaps
less intuitive, this is a better definition than before because it's
actually possible to give that string back to SET TIME ZONE and get the
same behavior, unlike what used to happen.

We did not previously mention the angle-bracket syntax when describing
POSIX timezone specifications; add some documentation so that people
can figure out what these strings do.  (There's still quite a lot of
undocumented functionality there, but anybody who really cares can
go read the POSIX spec to find out about it.  In practice most people
seem to prefer Olsen-style city names anyway.)
Ensure all files created for a single BufFile have the same resource owner.

Callers expect that they only have to set the right resource owner when
creating a BufFile, not during subsequent operations on it.  While we could
insist this be fixed at the caller level, it seems more sensible for the
BufFile to take care of it.  Without this, some temp files belonging to
a BufFile can go away too soon, eg at the end of a subtransaction,
leading to errors or crashes.

Reported and fixed by Andres Freund.  Back-patch to all active branches.
Retry after buffer locking failure during SPGiST index creation.

The original coding thought this case was impossible, but it can happen
if the bgwriter or checkpointer processes decide to write out an index
page while creation is still proceeding, leading to a bogus "unexpected
spgdoinsert() failure" error.  Problem reported by Jonathan S. Katz.

Teodor Sigaev
Fix subquery reference to non-populated MV in CMV.

A subquery reference to a matview should be allowed by CREATE
MATERIALIZED VIEW WITH NO DATA, just like a direct reference is.

Per bug report from Laurent Sartran.

Backpatch to 9.3.
Acquire appropriate locks when rewriting during RMV.

Since the query has not been freshly parsed when executing REFRESH
MATERIALIZED VIEW, locks must be explicitly taken before rewrite.

Backpatch to 9.3.

Andres Freund
Changed test case slightly so it doesn't have an unused typedef.
Prevent memory leaks from accumulating across printtup() calls.

Historically, printtup() has assumed that it could prevent memory leakage
by pfree'ing the string result of each output function and manually
managing detoasting of toasted values.  This amounts to assuming that
datatype output functions never leak any memory internally; an assumption
we've already decided to be bogus elsewhere, for example in COPY OUT.
range_out in particular is known to leak multiple kilobytes per call, as
noted in bug #8573 from Godfried Vanluffelen.  While we could go in and fix
that leak, it wouldn't be very notationally convenient, and in any case
there have been and undoubtedly will again be other leaks in other output
functions.  So what seems like the best solution is to run the output
functions in a temporary memory context that can be reset after each row,
as we're doing in COPY OUT.  Some quick experimentation suggests this is
actually a tad faster than the retail pfree's anyway.

This patch fixes all the variants of printtup, except for debugtup()
which is used in standalone mode.  It doesn't seem worth worrying
about query-lifespan leaks in standalone mode, and fixing that case
would be a bit tedious since debugtup() doesn't currently have any
startup or shutdown functions.

While at it, remove manual detoast management from several other
output-function call sites that had copied it from printtup().  This
doesn't make a lot of difference right now, but in view of recent
discussions about supporting "non-flattened" Datums, we're going to
want that code gone eventually anyway.

Back-patch to 9.2 where range_out was introduced.  We might eventually
decide to back-patch this further, but in the absence of known major
leaks in older output functions, I'll refrain for now.
Get rid of more cases of the "must detoast before output function" meme.

I missed that json.c was doing this too, because for some bizarre reason
it wasn't doing it adjacent to the output function call.
Fix parsing of xlog file name in pg_receivexlog.

The parsing of WAL filenames of segments larger than > 255 was broken,
making pg_receivexlog unable to restart streaming after stopping it.

The bug was introduced by the changes in 9.3 to represent WAL segment number
as a 64-bit integer instead of two ints, log and seg. To fix, replace the
plain sscanf call with XLogFromFileName macro, which does the conversion
from log+seg to a 64-bit integer correcly.

Reported by Mika Eloranta.