Fix possible crash with nested SubLinks.

An expression such as WHERE (... x IN (SELECT ...) ...) IN (SELECT ...)
could produce an invalid plan that results in a crash at execution time,
if the planner attempts to flatten the outer IN into a semi-join.
This happens because convert_testexpr() was not expecting any nested
SubLinks and would wrongly replace any PARAM_SUBLINK Params belonging
to the inner SubLink.  (I think the comment denying that this case could
happen was wrong when written; it's certainly been wrong for quite a long
time, since very early versions of the semijoin flattening logic.)

Per report from Teodor Sigaev.  Back-patch to all supported branches.
Add table name to VACUUM statement in matview.c.

The test only needs the one table to be vacuumed.  Vacuuming the
database may affect other tests.

Per gripe from Tom Lane.  Back-patch to 9.3, where the test was
was added.
Tweak placement of explicit ANALYZE commands in the regression tests.

Make the COPY test, which loads most of the large static tables used in
the tests, also explicitly ANALYZE those tables.  This allows us to get
rid of various ad-hoc, and rather redundant, ANALYZE commands that had
gotten stuck into various test scripts over time to ensure we got
consistent plan choices.  (We could have done a database-wide ANALYZE,
but that would cause stats to get attached to the small static tables
too, which results in plan changes compared to the historical behavior.
I'm not sure that's a good idea, so not going that far for now.)

Back-patch to 9.0, since 9.0 and 9.1 are currently sometimes failing
regression tests for lack of an "ANALYZE tenk1" in the subselect test.
There's no need for this in 8.4 since we didn't print any plans back
then.
Fix progress logging when scale factor is large.

Integer overflow showed minus percent and minus remaining time something like this.
  239300000 of 3800000000 tuples (-48%) done (elapsed 226.86 s, remaining -696.10 s).
Fix ancient docs/comments thinko: XID comparison is mod 2^32, not 2^31.

Pointed out by Gianni Ciolli.
Fix WAL-logging of setting the visibility map bit.

The operation that removes the remaining dead tuples from the page must
be WAL-logged before the setting of the VM bit. Otherwise, if you replay
the WAL to between those two records, you end up with the VM bit set, but
the dead tuples are still there.

Backpatch to 9.3, where this bug was introduced.
Don't let timeout interrupts happen unless ImmediateInterruptOK is set.

Serious oversight in commit 16e1b7a1b7f7ffd8a18713e83c8cd72c9ce48e07:
we should not allow an interrupt to take control away from mainline code
except when ImmediateInterruptOK is set.  Just to be safe, let's adopt
the same save-clear-restore dance that's been used for many years in
HandleCatchupInterrupt and HandleNotifyInterrupt, so that nothing bad
happens if a timeout handler invokes code that tests or even manipulates
ImmediateInterruptOK.

Per report of "stuck spinlock" failures from Christophe Pettus, though
many other symptoms are possible.  Diagnosis by Andres Freund.
Add HOLD/RESUME_INTERRUPTS in HandleCatchupInterrupt/HandleNotifyInterrupt.

This prevents a possible longjmp out of the signal handler if a timeout
or SIGINT occurs while something within the handler has transiently set
ImmediateInterruptOK.  For safety we must hold off the timeout or cancel
error until we're back in mainline, or at least till we reach the end of
the signal handler when ImmediateInterruptOK was true at entry.  This
syncs these functions with the logic now present in handle_sig_alarm.

AFAICT there is no live bug here in 9.0 and up, because I don't think we
currently can wait for any heavyweight lock inside these functions, and
there is no other code (except read-from-client) that will turn on
ImmediateInterruptOK.  However, that was not true pre-9.0: in older
branches ProcessIncomingNotify might block trying to lock pg_listener, and
then a SIGINT could lead to undesirable control flow.  It might be all
right anyway given the relatively narrow code ranges in which NOTIFY
interrupts are enabled, but for safety's sake I'm back-patching this.
Rework MultiXactId cache code

The original performs too poorly; in some scenarios it shows way too
high while profiling.  Try to make it a bit smarter to avoid excessive
cosst.  In particular, make it have a maximum size, and have entries be
sorted in LRU order; once the max size is reached, evict the oldest
entry to avoid it from growing too large.

Per complaint from Andres Freund in connection with new tuple freezing
code.
Fix typo
Fix inherited UPDATE/DELETE with UNION ALL subqueries.

Fix an oversight in commit b3aaf9081a1a95c245fd605dcf02c91b3a5c3a29: we do
indeed need to process the planner's append_rel_list when copying RTE
subqueries, because if any of them were flattenable UNION ALL subqueries,
the append_rel_list shows which subquery RTEs were pulled up out of which
other ones.  Without this, UNION ALL subqueries aren't correctly inserted
into the update plans for inheritance child tables after the first one,
typically resulting in no update happening for those child table(s).
Per report from Victor Yegorov.

Experimentation with this case also exposed a fault in commit
a7b965382cf0cb30aeacb112572718045e6d4be7: if an inherited UPDATE/DELETE
was proven totally dummy by constraint exclusion, we might arrive at
add_rtes_to_flat_rtable with root->simple_rel_array being NULL.  This
should be interpreted as not having any RelOptInfos.  I chose to code
the guard as a check against simple_rel_array_size, so as to also
provide some protection against indexing off the end of the array.

Back-patch to 9.2 where the faulty code was added.
Add "SHIFT_JIS" as an accepted encoding name for locale checking.

When locale is "ja_JP.SJIS", nl_langinfo(CODESET) returns "SHIFT_JIS"
on some platforms, at least on RedHat Linux. So the encoding/locale
match table (encoding_match_list) needs the entry. Otherwise client
encoding is set to SQL_ASCII.

Back patch to all supported branches.
Rework tuple freezing protocol

Tuple freezing was broken in connection to MultiXactIds; commit
8e53ae025de9 tried to fix it, but didn't go far enough.  As noted by
Noah Misch, freezing a tuple whose Xmax is a multi containing an aborted
update might cause locks in the multi to go ignored by later
transactions.  This is because the code depended on a multixact above
their cutoff point not having any lock-only member older than the cutoff
point for Xids, which is easily defeated in READ COMMITTED transactions.

The fix for this involves creating a new MultiXactId when necessary.
But this cannot be done during WAL replay, and moreover multixact
examination requires using CLOG access routines which are not supposed
to be used during WAL replay either; so tuple freezing cannot be done
with the old freeze WAL record.  Therefore, separate the freezing
computation from its execution, and change the WAL record to carry all
necessary information.  At WAL replay time, it's easy to re-execute
freezing because we don't need to re-compute the new infomask/Xmax
values but just take them from the WAL record.

While at it, restructure the coding to ensure all page changes occur in
a single critical section without much room for failures.  The previous
coding wasn't using a critical section, without any explanation as to
why this was acceptable.

In replication scenarios using the 9.3 branch, standby servers must be
upgraded before their master, so that they are prepared to deal with the
new WAL record once the master is upgraded; failure to do so will cause
WAL replay to die with a PANIC message.  Later upgrade of the standby
will allow the process to continue where it left off, so there's no
disruption of the data in the standby in any case.  Standbys know how to
deal with the old WAL record, so it's okay to keep the master running
the old code for a while.

In master, the old freeze WAL record is gone, for cleanliness' sake;
there's no compatibility concern there.

Backpatch to 9.3, where the original bug was introduced and where the
previous fix was backpatched.

Andres Freund and Álvaro Herrera