ability to lock relations as they scan pg_inherits, and to ignore any
relations that have disappeared by the time we get lock on them.  This
makes uses of these functions safe against concurrent DROP operations
on child tables: we will effectively ignore any just-dropped child,
rather than possibly throwing an error as in recent bug report from
Thomas Johansson (and similar past complaints).  The behavior should
not change otherwise, since the code was acquiring those same locks
anyway, just a little bit later.

An exception is LockTableCommand(), which is still behaving unsafely;
but that seems to require some more discussion before we change it.

find_inheritance_children() and find_all_inheritors().  I got annoyed that
these are buried inside the planner but mostly used elsewhere.  So, create
a new file catalog/pg_inherits.c and put them there, along with a couple
of other functions that search pg_inherits.

The code that modifies pg_inherits is (still) in tablecmds.c --- it's
kind of entangled with unrelated code that modifies pg_depend and other
stuff, so pulling it out seemed like a bigger change than I wanted to make
right now.  But this file provides a natural home for it if anyone ever
gets around to that.

This commit just moves code around; it doesn't change anything, except
I succumbed to the temptation to make a couple of trivial optimizations
in typeInheritsFrom().

of AND/OR clause branches that predtest.c would attempt to deal with.  As
noted in bug #4721, that change disabled proof attempts for sizes of problems
that people are actually expecting it to work for.  The original complaint
it was trying to solve was O(N^2) behavior for long IN-lists, so let's try
applying the limit to just ScalarArrayOpExprs rather than everything.
Another case of "foolish consistency" I fear.

Back-patch to 8.2, same as the previous patch was.

Add some details about the name=value format of auth options.

a note about the certificates chains patch just applied.

Andrew Gierth

predicate_refuted_by: if either top-level input is a single-element list,
reduce it to its lone member before proceeding.  This avoids
a useless level of AND-recursion within the recursive proof routines.
It's worth doing because, for example, if the clause is a 100-element
list and the predicate is a 1-element list then we'd otherwise strip
the predicate's list structure 100 times as we iterate through the clause.
It's only needed at top level because there won't be any trivial ANDs below
that --- this situation is an artifact of the decision to represent even
single-item conditions as Lists in the "implicit AND" format, and that format
is only used at the top level of any predicate or restriction condition.

in its CREATE DATABASE commands only for databases that have settings
different from the installation defaults.  This is a low-tech method of
avoiding unnecessary platform dependencies in dump files.  Eventually we ought
to have a platform-independent way of specifying LC_COLLATE and LC_CTYPE, but
that's not going to happen for 8.4, and this patch at least avoids the issue
for people who aren't setting up per-database locales.  ENCODING doesn't have
the platform dependency problem, but it seems consistent to make it act the
same as the locale settings.

joins a bit better, ie, understand the differing cost functions for matched
and unmatched outer tuples.  There is more that could be done in cost_hashjoin
but this already helps a great deal.  Per discussions with Robert Haas.

tsearch2 tests. This should make 'comet_moth' buildfarm member pass
contrib check. Zdenek Kotala.

linkage on Win32.

Tested by Hiroshi Saito

a toast table to be built, even if the sum-of-column-widths calculation
indicates one isn't needed.  This is needed by pg_migrator because if the
old table has a toast table, we have to migrate over the toast table since
it might contain some live data, even though subsequent column drops could
mean that no recently-added rows could require toasting.

pgbench_history, and pgbench_tellers, rather than just accounts, branches,
history, and tellers.  This is to prevent accidental conflicts with real
application tables, as has been reported to happen at least once.  Also
remove the automatic "SET search_path = public" that it did at startup,
as this seems to restrict testing flexibility without actually buying much.
Per proposal by Joshua Drake and ensuing discussion.

Joshua Drake and Tom Lane

restrictions specified for semijoins in optimizer/README, to wit that
you can't reassociate outer joins into or out of the RHS of a semijoin.
Per report from Heikki.

you can end up with an unrecoverable backup if you start a new base backup
right after finishing archive recovery. In that scenario, the redo pointer of
the checkpoint that pg_start_backup() writes points to the XLOG segment where
the timeline-changing end-of-archive-recovery checkpoint is. The beginning
of that segment contains pages with the old timeline ID, and we don't accept
that in recovery unless we find a history file covering the old timeline ID.
If you omit pg_xlog from the base backup and clear the archive directory
before starting the backup, there will be no such history file available.

The bug is present in all versions since PITR was introduced in 8.0, but I'm
back-patching only back to 8.2. Earlier versions didn't have XLOG switch
records, making this fix unfeasible. Given the lack of reports until now,
it doesn't seem worthwhile to spend more effort to fix 8.0 and 8.1.

Per report and suggestion by Mikael Krantz

can be pushed to the top of the join tree, we update both the relids and
qualscope variables to keep them in sync.  This prevents a possible later
failure of an Assert clause, and affects nothing else since qualscope isn't
used later except for that Assert.  At the moment the Assert shouldn't be
reachable when we've pushed the qual up; but this is cheap insurance, and
it's more sensible anyway in terms of the overall logic of the routine.
Per analysis of a bug report from Stefan Huehner.

I'm not back-patching this since it's just future-proofing; but if anyone
gets tempted to change check_outerjoin_delay again in the back branches,
this might be needed.

must be used for the new database, except when copying from template0.
This is the same rule that we now enforce for locale settings, and it has
the same motivation: databases other than template0 might contain data that
would be invalid according to a different setting.  This represents another
step in a continuing process of locking down ways in which encoding violations
could occur inside the backend.  Per discussion of a few days ago.

In passing, fix pre-existing breakage of mbregress.sh, and fix up a couple
of ereport() calls in dbcommands.c that failed to specify sqlstate codes.

standard_conforming_strings is on.

locales are database-wide, not server-wide.

affected by CloseHandle() or Sleep().

Every other ereport in scan.l has one, this should too.

will still be performed if something in a backend process calls exit()
directly, instead of going through proc_exit() as we prefer.  This is a second
response to the issue that we might load third-party code that doesn't know it
should not call exit().  Such a call will now cause a reasonably graceful
backend shutdown, if possible.  (Of course, if the reason for the exit() call
is out-of-memory or some such, we might not be able to recover, but at least
we will try.)

a backend has done exit(0) or exit(1) without having disengaged itself
from shared memory.  We are at risk for this whenever third-party code is
loaded into a backend, since such code might not know it's supposed to go
through proc_exit() instead.  Also, it is reported that under Windows
there are ways to externally kill a process that cause the status code
returned to the postmaster to be indistinguishable from a voluntary exit
(thank you, Microsoft).  If this does happen then the system is probably
hosed --- for instance, the dead session might still be holding locks.
So the best recovery method is to treat this like a backend crash.

The dead man switch is armed for a particular child process when it
acquires a regular PGPROC, and disarmed when the PGPROC is released;
these should be the first and last touches of shared memory resources
in a backend, or close enough anyway.  This choice means there is no
coverage for auxiliary processes, but I doubt we need that, since they
shouldn't be executing any user-provided code anyway.

This patch also improves the management of the EXEC_BACKEND
ShmemBackendArray array a bit, by reducing search costs.

Although this problem is of long standing, the lack of field complaints
seems to mean it's not critical enough to risk back-patching; at least
not till we get some more testing of this mechanism.

points where we step right or left to the next page.  This should ensure
reasonable response time to a query cancel request during an unsuccessful
index scan, as seen in recent gripe from Marc Cousin.  It's a bit trickier
than it might seem at first glance, because CHECK_FOR_INTERRUPTS() is a no-op
if executed while holding a buffer lock.  So we have to do it just at the
point where we've dropped one page lock and not yet acquired the next.

Remove CHECK_FOR_INTERRUPTS calls at the top level of btgetbitmap and
hashgetbitmap, since they're pointless given the added checks.

I think that GIST is okay already --- at least, there's a CHECK_FOR_INTERRUPTS
at a plausible-looking place in gistnext().  I don't claim to know GIN well
enough to try to poke it for this, if indeed it has a problem at all.

This is a pre-existing issue, but in view of the lack of prior complaints
I'm not going to risk back-patching.

standard_conforming_strings is not on, for security reasons.

ANALYZE's total sample.  The original coding is at risk of overflow for
statistics targets exceeding about 2675; this was not a problem before
8.4 but it is now.  Per bug #4793 from Dennis Noordsij.

it fails because the shared memory segment already exists. This
means it can take up to 10 seconds before it reports the error
if it *does* exist, but hopefully it will make the system capable
of restarting even when the server is under high load.

volatility columns localizable.

to make sure that the error code is reset, as a precaution in
case the API doesn't properly reset it on success. This could
be necessary, since we check the error value even if the function
doesn't fail for specific success cases.

tree with references to the appropriate URLs.

Robert Haas

whether it failed.  Modelled after catcache.c's usage of DlList, per suggestion
from Tom.

Fujii Masao

a parenthetical remark.

canonicalized.  Avoid the need to elog(FATAL) on out-of-memory.