Improve pg_upgrade's load_directory() function.

Error out on out-of-memory, rather than returning -1, which the sole
existing caller wasn't checking for anyway.  There doesn't seem to be
any use-case for making the caller check for failure here.

Detect failure return from readdir().

Use a less platform-dependent method of calculating the entrysize.
It's possible, but not yet confirmed, that this explains bug #6733,
in which Mike Wilson reports a pg_upgrade crash that did not occur
in 9.1.  (Note that load_directory is effectively new code in 9.2,
at least on platforms that have scandir().)

Fix up comments, avoid uselessly using two counters, reduce the number
of realloc calls to something sane.
Get rid of useless global variable in pg_upgrade.

Since the scandir() emulation was taken out of pg_upgrade, there's
no longer any need for scandir_file_pattern to exist as a global
variable.  Replace it with a local in the one remaining function
that was making use of it.
Syntax support and documentation for event triggers.

They don't actually do anything yet; that will get fixed in a
follow-on commit.  But this gets the basic infrastructure in place,
including CREATE/ALTER/DROP EVENT TRIGGER; support for COMMENT,
SECURITY LABEL, and ALTER EXTENSION .. ADD/DROP EVENT TRIGGER;
pg_dump and psql support; and documentation for the anticipated
initial feature set.

Dimitri Fontaine, with review and a bunch of additional hacking by me.
Thom Brown extensively reviewed earlier versions of this patch set,
but there's not a whole lot of that code left in this commit, as it
turns out.
Fix management of pendingOpsTable in auxiliary processes.

mdinit() was misusing IsBootstrapProcessingMode() to decide whether to
create an fsync pending-operations table in the current process.  This led
to creating a table not only in the startup and checkpointer processes as
intended, but also in the bgwriter process, not to mention other auxiliary
processes such as walwriter and walreceiver.  Creation of the table in the
bgwriter is fatal, because it absorbs fsync requests that should have gone
to the checkpointer; instead they just sit in bgwriter local memory and are
never acted on.  So writes performed by the bgwriter were not being fsync'd
which could result in data loss after an OS crash.  I think there is no
live bug with respect to walwriter and walreceiver because those never
perform any writes of shared buffers; but the potential is there for
future breakage in those processes too.

To fix, make AuxiliaryProcessMain() export the current process's
AuxProcType as a global variable, and then make mdinit() test directly for
the types of aux process that should have a pendingOpsTable.  Having done
that, we might as well also get rid of the random bool flags such as
am_walreceiver that some of the aux processes had grown.  (Note that we
could not have fixed the bug by examining those variables in mdinit(),
because it's called from BaseInit() which is run by AuxiliaryProcessMain()
before entering any of the process-type-specific code.)

Back-patch to 9.2, where the problem was introduced by the split-up of
bgwriter and checkpointer processes.  The bogus pendingOpsTable exists
in walwriter and walreceiver processes in earlier branches, but absent
any evidence that it causes actual problems there, I'll leave the older
branches alone.
Fix statistics breakage from bgwriter/checkpointer process split.

ForwardFsyncRequest() supposed that it could only be called in regular
backends, which used to be true; but since the splitup of bgwriter and
checkpointer, it is also called in the bgwriter.  We do not want to count
such calls in pg_stat_bgwriter.buffers_backend statistics, so fix things
so that they aren't.

(It's worth noting here that this implies an alarmingly large increase in
the expected amount of cross-process fsync request traffic, which may well
mean that the process splitup was not such a hot idea.)
Refactor the way code is shared between some range type functions.

Functions like range_eq, range_before etc. are exposed at the SQL-level, but
they're also used internally by the GiST consistent support function. The
code sharing was done by a hack, TrickFunctionCall2, which relied on the
knowledge that all the functions used fn_extra the same way. This commit
splits the functions into internal versions that take a TypeCacheEntry as
argument, and thin wrappers to expose the functions at the SQL-level. The
internal versions can then be called directly and in a less hacky way from
the GiST consistent function.

This is just cosmetic, but backpatch to 9.2 anyway, to avoid having a
different version of this code in the 9.2 branch. That would make
backpatching fixes in this area more difficult.

Alexander Korotkov
Send only one FORGET_RELATION_FSYNC request when dropping a relation.

We were sending one per fork, but a little bit of refactoring allows us
to send just one request with forknum == InvalidForkNumber.  This not only
reduces pressure on the shared-memory request queue, but saves repeated
traversals of the checkpointer's hash table.
Rethink checkpointer's fsync-request table representation.

Instead of having one hash table entry per relation/fork/segment, just have
one per relation, and use bitmapsets to represent which specific segments
need to be fsync'd.  This eliminates the need to scan the whole hash table
to implement FORGET_RELATION_FSYNC, which fixes the O(N^2) behavior
recently demonstrated by Jeff Janes for cases involving lots of TRUNCATE or
DROP TABLE operations during a single checkpoint cycle.  Per an idea from
Robert Haas.

(FORGET_DATABASE_FSYNC still sucks, but since dropping a database is a
pretty expensive operation anyway, we'll live with that.)

In passing, improve the delayed-unlink code: remove the pass over the list
in mdpreckpt, since it wasn't doing anything for us except supporting a
useless Assert in mdpostckpt, and fix mdpostckpt so that it will absorb
fsync requests every so often when clearing a large backlog of deletion
requests.
Make new event trigger facility actually do something.

Commit 3855968f328918b6cd1401dd11d109d471a54d40 added syntax, pg_dump,
psql support, and documentation, but the triggers didn't actually fire.
With this commit, they now do.  This is still a pretty basic facility
overall because event triggers do not get a whole lot of information
about what the user is trying to do unless you write them in C; and
there's still no option to fire them anywhere except at the very
beginning of the execution sequence, but it's better than nothing,
and a good building block for future work.

Along the way, add a regression test for ALTER LARGE OBJECT, since
testing of event triggers reveals that we haven't got one.

Dimitri Fontaine and Robert Haas
Fix whole-row Var evaluation to cope with resjunk columns (again).

When a whole-row Var is reading the result of a subquery, we need it to
ignore any "resjunk" columns that the subquery might have evaluated for
GROUP BY or ORDER BY purposes.  We've hacked this area before, in commit
68e40998d058c1f6662800a648ff1e1ce5d99cba, but that fix only covered
whole-row Vars of named composite types, not those of RECORD type; and it
was mighty klugy anyway, since it just assumed without checking that any
extra columns in the result must be resjunk.  A proper fix requires getting
hold of the subquery's targetlist so we can actually see which columns are
resjunk (whereupon we can use a JunkFilter to get rid of them).  So bite
the bullet and add some infrastructure to make that possible.

Per report from Andrew Dunstan and additional testing by Merlin Moncure.
Back-patch to all supported branches.  In 8.3, also back-patch commit
292176a118da6979e5d368a4baf27f26896c99a5, which for some reason I had
not done at the time, but it's a prerequisite for this change.
connoinherit may be true only for CHECK constraints

The code was setting it true for other constraints, which is
bogus.  Doing so caused bogus catalog entries for such constraints, and
in particular caused an error to be raised when trying to drop a
constraint of types other than CHECK from a table that has children,
such as reported in bug #6712.

In 9.2, additionally ignore connoinherit=true for other constraint
types, to avoid having to force initdb; existing databases might already
contain bogus catalog entries.

Includes a catversion bump (in HEAD only).

Bug report from Miroslav Šulc
Analysis from Amit Kapila and Noah Misch; Amit also contributed the patch.
pg_dump: Simplify mkdir() error checking

mkdir() can check for errors itself.  We don't need to code that
ourselves again.
Remove prepared transactions from main isolation test schedule.

There is no point in running this test when prepared transactions are disabled,
which is the default. New make targets that include the test are provided. This
will save some useless waste of cycles on buildfarm machines.

Backpatch to 9.1 where these tests were introduced.
Temporary patch to try to debug why event trigger patch broke Windows.

Apologies for the ugliness.
Remove now unneeded results file for disabled prepared transactions case.
Repair plpgsql_validator breakage.

Commit 3a0e4d36ebd7f477822d5bae41ba121a40d22ccc arranged to
reference stack-allocated variables after they were out of scope.
That's no good, so let's arrange to not do that after all.
Revert temporary patch to debug Windows breakage.

This reverts commit 0a248208a038d7847ef98996c6b70209d782415c.
Account for SRFs in targetlists in planner rowcount estimates.

We made use of the ROWS estimate for set-returning functions used in FROM,
but not for those used in SELECT targetlists; which is a bit of an
oversight considering there are common usages that require the latter
approach.  Improve that.  (I had initially thought it might be worth
folding this into cost_qual_eval, but after investigation concluded that
that wouldn't be very helpful, so just do it separately.)  Per complaint
from David Johnston.

Back-patch to 9.2, but not further, for fear of destabilizing plan choices
in existing releases.
Suppress volatile-related warning seen in some compilers.

Antique versions of gcc complain about vars that are initialized outside
PG_TRY and then modified within it.  Rather than marking the var volatile,
expend one more line of code.
Use --nosync during make check's initdb call.

We left this out of commit b966dd6c4228d696b291c1cdcb5ab8c8475fefa8
so as to get some more buildfarm testing of the new fsync code in initdb.
But since no problems have turned up, it's probably time to save the
cycles.