This reverts commit e2b3c21b.

Normally each module is tested in aq database named contrib_regression,
which is dropped and recreated at the beginhning of each pg_regress run.
This mode, enabled by adding USE_MODULE_DB=1 to the make command line,
runs most modules in a database with the module name embedded in it.

This will make testing pg_upgrade on clusters with the contrib modules
a lot easier.

Still to be done: adapt to the MSVC build system.

Backpatch to 9.0, which is the earliest version it is reasonably possible
to test upgrading from.

    In pg_upgrade, remove pg_restore's --single-transaction option,
    as it throws errors in certain cases.

certain cases.

status output for dump/restore.

It's not safe to examine a shared buffer without any lock.

--single-transaction to restore each database schema.  This yields
performance improvements for databases with many tables.  Also, remove
split_old_dump() as it is no longer needed.

consistency.

Per suggestion from Tom.

This removes exisiting PG settings from the environment for
pg_upgrade tests, just like pg_regress does.

Commit 8cb53654, which introduced DROP
INDEX CONCURRENTLY, managed to break CREATE INDEX CONCURRENTLY via a poor
choice of catalog state representation.  The pg_index state for an index
that's reached the final pre-drop stage was the same as the state for an
index just created by CREATE INDEX CONCURRENTLY.  This meant that the
(necessary) change to make RelationGetIndexList ignore about-to-die indexes
also made it ignore freshly-created indexes; which is catastrophic because
the latter do need to be considered in HOT-safety decisions.  Failure to
do so leads to incorrect index entries and subsequently wrong results from
queries depending on the concurrently-created index.

To fix, add an additional boolean column "indislive" to pg_index, so that
the freshly-created and about-to-die states can be distinguished.  (This
change obviously is only possible in HEAD.  This patch will need to be
back-patched, but in 9.2 we'll use a kluge consisting of overloading the
formerly-impossible state of indisvalid = true and indisready = false.)

In addition, change CREATE/DROP INDEX CONCURRENTLY so that the pg_index
flag changes they make without exclusive lock on the index are made via
heap_inplace_update() rather than a normal transactional update.  The
latter is not very safe because moving the pg_index tuple could result in
concurrent SnapshotNow scans finding it twice or not at all, thus possibly
resulting in index corruption.  This is a pre-existing bug in CREATE INDEX
CONCURRENTLY, which was copied into the DROP code.

In addition, fix various places in the code that ought to check to make
sure that the indexes they are manipulating are valid and/or ready as
appropriate.  These represent bugs that have existed since 8.2, since
a failed CREATE INDEX CONCURRENTLY could leave a corrupt or invalid
index behind, and we ought not try to do anything that might fail with
such an index.

Also fix RelationReloadIndexInfo to ensure it copies all the pg_index
columns that are allowed to change after initial creation.  Previously we
could have been left with stale values of some fields in an index relcache
entry.  It's not clear whether this actually had any user-visible
consequences, but it's at least a bug waiting to happen.

In addition, do some code and docs review for DROP INDEX CONCURRENTLY;
some cosmetic code cleanup but mostly addition and revision of comments.

This will need to be back-patched, but in a noticeably different form,
so I'm committing it to HEAD before working on the back-patch.

Problem reported by Amit Kapila, diagnosis by Pavan Deolassee,
fix by Tom Lane and Andres Freund.

centralizing error/shutdown code.

pg_malloc/pg_free.

error and errno != ENOENT.

The previous definitions of these GUC variables allowed them to range
up to INT_MAX, but in point of fact the underlying code would suffer
overflows or other errors with large values.  Reduce the maximum values
to something that won't misbehave.  There's no apparent value in working
harder than this, since very large delays aren't sensible for any of
these.  (Note: the risk with archive_timeout is that if we're late
checking the state, the timestamp difference it's being compared to
might overflow.  So we need some amount of slop; the choice of INT_MAX/2
is arbitrary.)

Per followup investigation of bug #7670.  Although this isn't a very
significant fix, might as well back-patch.

existence via open(), rather than collecting a directory listing and
looking up matching relfilenode files with sequential scans of the
array.  This speeds up pg_upgrade by 2x for a large number of tables,
e.g. 16k.

Per observation by Ants Aasma.

As pointed out by Alvaro.

improve performance when restoring the schema from the old cluster.

Backpatch to 9.2.

... and have sepgsql use it to determine whether to check permissions
during certain operations.  Indexes that are being created as a result
of REINDEX, for instance, do not need to have their permissions checked;
they were already checked when the index was created.

Author: KaiGai Kohei, slightly revised by me

Per Thom Brown.

rather than just storing a pointer.

Per compiler warning.

Numerous flex and bison make rules have appeared in the source tree
over time, and they are all virtually identical, so we can replace
them by pattern rules with some variables for customization.

Users of pgxs will also be able to benefit from this.

The HINTs generated for these error cases vary across builds.  We
could try to work around that, but the test cases aren't really useful
enough to justify taking any trouble.

Per buildfarm.

dblink now has its own validator function dblink_fdw_validator(), which is
better than the core function postgresql_fdw_validator() because it gets
the list of legal options from libpq instead of having a hard-wired list.

Make the dblink extension module provide a standard foreign data wrapper
dblink_fdw that encapsulates use of this validator, and recommend use of
that wrapper instead of making up wrappers on the fly.

Unfortunately, because ad-hoc wrappers *were* recommended practice
previously, it's not clear when we can get rid of postgresql_fdw_validator
without causing upgrade problems.  But this is a step in the right
direction.

Shigeru Hanada, reviewed by KaiGai Kohei

Backpatch to 9.2.

e.g. fsync  2103.613 ops/sec (   475 microsecs/op)

Peter Geoghegan

This allows logging only some fraction of transactions, greatly reducing
the amount of log generated.

Tomas Vondra, reviewed by Robert Haas and Jeff Janes.

Backpatch to 9.2.

On some platforms these functions return NULL, rather than the more common
practice of returning a pointer to a zero-sized block of memory.  Hack our
various wrapper functions to hide the difference by substituting a size
request of 1.  This is probably not so important for the callers, who
should never touch the block anyway if they asked for size 0 --- but it's
important for the wrapper functions themselves, which mistakenly treated
the NULL result as an out-of-memory failure.  This broke at least pg_dump
for the case of no user-defined aggregates, as per report from
Matthew Carrington.

Back-patch to 9.2 to fix the pg_dump issue.  Given the lack of previous
complaints, it seems likely that there is no live bug in previous releases,
even though some of these functions were in place before that.

We had a number of variants on the theme of "malloc or die", with the
majority named like "pg_malloc", but by no means all.  Standardize on the
names pg_malloc, pg_malloc0, pg_realloc, pg_strdup.  Get rid of pg_calloc
entirely in favor of using pg_malloc0.

This is an essentially cosmetic change, so no back-patch.  (I did find
a couple of places where psql and pg_dump were using plain malloc or
strdup instead of the pg_ versions, but they don't look significant
enough to bother back-patching.)

objects does not match between the old and new clusters.

Backpatch to 9.2.

entries are not dumped.   This fixes an error caused by
droping/recreating the information_schema, but other failures were also
possible.

Backpatch to 9.2.

comparison;  also report the old/new values if they don't match.

Backpatch to 9.2.

On reflection (especially after noticing how many buildfarm critters have
__builtin_types_compatible_p but not _Static_assert), it seems like we
ought to try a bit harder to make these macros do something everywhere.
The initial cut at it would have been no help to code that is compiled only
on platforms without _Static_assert, for instance; and in any case not all
our contributors do their initial coding on the latest gcc version.

Some googling about static assertions turns up quite a bit of prior art
for making it work in compilers that lack _Static_assert.  The method
that seems closest to our needs involves defining a struct with a bit-field
that has negative width if the assertion condition fails.  There seems no
reliable way to get the error message string to be output, but throwing a
compile error with a confusing message is better than missing the problem
altogether.

In the same spirit, if we don't have __builtin_types_compatible_p we can at
least insist that the variable have the same width as the type.  This won't
catch errors such as "wrong pointer type", but it's far better than
nothing.

In addition to changing the macro definitions, adjust a
compile-time-constant Assert in contrib/hstore to use StaticAssertStmt,
so we can get some buildfarm coverage on whether that macro behaves sanely
or not.  There's surely more places that could be converted, but this is
the first one I came across.

This mirrors the behavior of pg_regress and makes the test run much
faster.

It is no longer used, but was still being checked for.

bug #7548 from Reinhard Max