The logic introduced in commit b69bf30b
and repaired in commits 669c7d20 and
7be47c56 helps to ensure that we don't
overwrite old multixact member information while it is still needed,
but a user who creates many large multixacts can still exhaust the
member space (and thus start getting errors) while autovacuum stands
idly by.

To fix this, progressively ramp down the effective value (but not the
actual contents) of autovacuum_multixact_freeze_max_age as member space
utilization increases.  This makes autovacuum more aggressive and also
reduces the threshold for a manual VACUUM to perform a full-table scan.

This patch leaves unsolved the problem of ensuring that emergency
autovacuums are triggered even when autovacuum=off.  We'll need to fix
that via a separate patch.

Thomas Munro and Robert Haas

src/tools/backend was removed back in 63f1ccd8, but
backend/storage/lmgr/README didn't get the memo.

Author: Amit Langote

Buildfarm member magpie sorted the output differently than intended by
Peter. "Resolve" the problem by simply not aggregating, it's not that
many lines.

The newly added ON CONFLICT clause allows to specify an alternative to
raising a unique or exclusion constraint violation error when inserting.
ON CONFLICT refers to constraints that can either be specified using a
inference clause (by specifying the columns of a unique constraint) or
by naming a unique or exclusion constraint.  DO NOTHING avoids the
constraint violation, without touching the pre-existing row.  DO UPDATE
SET ... [WHERE ...] updates the pre-existing tuple, and has access to
both the tuple proposed for insertion and the existing tuple; the
optional WHERE clause can be used to prevent an update from being
executed.  The UPDATE SET and WHERE clauses have access to the tuple
proposed for insertion using the "magic" EXCLUDED alias, and to the
pre-existing tuple using the table name or its alias.

This feature is often referred to as upsert.

This is implemented using a new infrastructure called "speculative
insertion". It is an optimistic variant of regular insertion that first
does a pre-check for existing tuples and then attempts an insert.  If a
violating tuple was inserted concurrently, the speculatively inserted
tuple is deleted and a new attempt is made.  If the pre-check finds a
matching tuple the alternative DO NOTHING or DO UPDATE action is taken.
If the insertion succeeds without detecting a conflict, the tuple is
deemed inserted.

To handle the possible ambiguity between the excluded alias and a table
named excluded, and for convenience with long relation names, INSERT
INTO now can alias its target table.

Bumps catversion as stored rules change.

Author: Peter Geoghegan, with significant contributions from Heikki
    Linnakangas and Andres Freund. Testing infrastructure by Jeff Janes.
Reviewed-By: Heikki Linnakangas, Andres Freund, Robert Haas, Simon Riggs,
    Dean Rasheed, Stephen Frost and many others.

Previously, relation range table entries used a single Bitmapset field
representing which columns required either UPDATE or INSERT privileges,
despite the fact that INSERT and UPDATE privileges are separately
cataloged, and may be independently held.  As statements so far required
either insert or update privileges but never both, that was
sufficient. The required permission could be inferred from the top level
statement run.

The upcoming INSERT ... ON CONFLICT UPDATE feature needs to
independently check for both privileges in one statement though, so that
is not sufficient anymore.

Bumps catversion as stored rules change.

Author: Peter Geoghegan
Reviewed-By: Andres Freund

The minmax opclass was using the wrong support functions when
cross-datatypes queries were run.  Instead of trying to fix the
pg_amproc definitions (which apparently is not possible), use the
already correct pg_amop entries instead.  This requires jumping through
more hoops (read: extra syscache lookups) to obtain the underlying
functions to execute, but it is necessary for correctness.

Author: Emre Hasegeli, tweaked by Álvaro
Review: Andreas Karlsson

Also change BrinOpcInfo to record each stored type's typecache entry
instead of just the OID.  Turns out that the full type cache is
necessary in brin_deform_tuple: the original code used the indexed
type's byval and typlen properties to extract the stored tuple, which is
correct in Minmax; but in other implementations that want to store
something different, that's wrong.  The realization that this is a bug
comes from Emre also, but I did not use his patch.

I also adopted Emre's regression test code (with smallish changes),
which is more complete.

The old formula didn't have enough parentheses, so it would do the wrong
thing, and it used / rather than % to find a remainder.  The effect of
these oversights is that the stop point chosen by the logic introduced in
commit b69bf30b might be rather
meaningless.

Thomas Munro, reviewed by Kevin Grittner, with a whitespace tweak by me.

Report by Mario Valdez

The Service Control Manager should be notified regularly during a shutdown
that takes a long time. Previously we would increaes the counter, but forgot
to actually send the notification to the system. The loop counter was also
incorrectly initalized in the event that the startup of the system took long
enough for it to increase, which could cause the shutdown process not to wait
as long as expected.

Krystian Bigaj, reviewed by Michael Paquier

Michael Paquier, spotted using Coverity

Michael Paquier, spotted using Coverity

Per request from Peter Eisentraut.

These functions should return SETOF TEXT[], like the core functions they
are wrappers for; but they were incorrectly declared as returning just
TEXT[].  This mistake had two results: first, if there was no match you got
a scalar null result, whereas what you should get is an empty set (zero
rows).  Second, the 'g' flag was effectively ignored, since you would get
only one result array even if there were multiple matches, as reported by
Jeff Certain.

While ignoring 'g' is a clear bug, the behavior for no matches might well
have been thought to be the intended behavior by people who hadn't compared
it carefully to the core regexp_matches() functions.  So we should tread
carefully about introducing this change in the back branches.  Still, it
clearly is a bug and so providing some fix is desirable.

After discussion, the conclusion was to introduce the change in a 1.1
version of the citext extension (as we would need to do anyway); 1.0 still
contains the incorrect behavior.  1.1 is the default and only available
version in HEAD, but it is optional in the back branches, where 1.0 remains
the default version.  People wishing to adopt the fix in back branches will
need to explicitly do ALTER EXTENSION citext UPDATE TO '1.1'.  (I also
provided a downgrade script in the back branches, so people could go back
to 1.0 if necessary.)

This should be called out as an incompatible change in the 9.5 release
notes, although we'll also document it in the next set of back-branch
release notes.  The notes should mention that any views or rules that use
citext's regexp_matches() functions will need to be dropped before
upgrading to 1.1, and then recreated again afterwards.

Back-patch to 9.1.  The bug goes all the way back to citext's introduction
in 8.4, but pre-9.1 there is no extension mechanism with which to manage
the change.  Given the lack of previous complaints it seems unnecessary to
change this behavior in 9.0, anyway.

This commit adds the following functions:
    box(point) -> box
    bound_box(box, box) -> box
    inet_same_family(inet, inet) -> bool
    inet_merge(inet, inet) -> cidr
    range_merge(anyrange, anyrange) -> anyrange

The first of these is also used to implement a new assignment cast from
point to box.

These functions are the first part of a base to implement an "inclusion"
operator class for BRIN, for multidimensional data types.

Author: Emre Hasegeli
Reviewed by: Andreas Karlsson

pg_win32_is_junction() was a typo for pgwin32_is_junction().  open()
was used not only in a two-argument form, which breaks on Windows,
but also where BasicOpenFile() should have been used.

Per reports from Andrew Dunstan and David Rowley.

Python 2.3 does not have the sorted() function, so do it the long way.

Author: Erik Rijkers <er@xs4all.nl>

This makes the executor code more consistent.  It also removes
an apparently superfluous NULL test in nodeGroup.c.

Qingqing Zhou, reviewed by Tom Lane, and further revised by me.

The text search functions that involve parsing raw text into lexemes are
remarkably CPU-intensive, so estimating them at the same cost as most other
built-in functions seems like a mistake; moreover, doing so turns out to
discourage the optimizer from using functional indexes on these functions.
After some debate, we've agreed to raise procost from 1 to 100 for
to_tsvector(), plainto_tsvector(), to_tsquery(), ts_headline(),
ts_match_tt(), and ts_match_tq(), which are all the text search functions
that parse raw text.

Also increase procost for the 2-argument form of ts_rewrite()
(tsquery_rewrite_query); while this function doesn't do text parsing,
it does execute a user-supplied SQL query, so its previous procost of 1 is
clearly a drastic underestimate.  It seems reasonable to assign it the same
cost we assign to PL functions by default, so 100 is the number here too.

I did not bother bumping catversion for this change, since it does not
break catalog compatibility with the server executable nor result in
any regression test changes.

Per complaint from Andrew Gierth and subsequent discussion.

Otherwise, if there's another crash, some writes from after the first
crash might make it to disk while writes from before the crash fail
to make it to disk.  This could lead to data corruption.

Back-patch to all supported versions.

Abhijit Menon-Sen, reviewed by Andres Freund and slightly revised
by me.

prev_regbuf was never set, and therefore the same-rel flag was never set on
WAL records.

Report and fix by Zhanq Zq

The first bug is not releasing a tupdesc when doing an early return out
of the function. The second bug is a logic error in choosing when to do
an early return if given an empty jsonb object.

Bug reports from Pavel Stehule and Tom Lane respectively.

Backpatch to 9.4 where these were introduced.

Commit ef3f9e64 suppressed one cause of warnings here, but
recent clang on OS X is still unhappy because we're passing a "long"
to abs().  The fact that tm_gmtoff is declared as long is no doubt a
hangover from days when int might be only 16 bits; but Postgres has
never been able to run on such machines, so we can just cast it to int
with no worries.  For consistency, also cast to int in the other
uses of tm_gmtoff in this stanza.

Note: this code is still broken on machines that don't follow C99
integer-division-truncates-towards-zero rules.  Given the lack of
complaints about it, I don't feel a large desire to complicate things
enough to cope with the pre-C99 rules.

When altering the deferredness state of a foreign key constraint, we
correctly updated the catalogs and then invalidated the relcache state for
the target relation ... but that's not the only relation with relevant
triggers.  Must invalidate the other table as well, or the state change
fails to take effect promptly for operations triggered on the other table.
Per bug #13224 from Christian Ullrich.

In passing, reorganize regression test case for this feature so that it
isn't randomly injected into the middle of an unrelated test sequence.

Oversight in commit f177cbfe.  Back-patch
to 9.4 where the faulty code was added.

These modules were all missing essential Windows scaffolding, including
resources files and descriptions, and links to the relevant library
import files. This latter item means that the modules can't be built
with pgxs on Windows, as we don't install the import files. If we ever
decide to install them this restriction could probably be removed.

Also, as with plperl we need to make sure that perl's CORE directory is
last on the include list, as on Windows it appears to contain some
headers with names that clash with names of some headers we include.

By converting to using forward slashes at configure time we avoid
having to repeat the logic anywhere that this is needed, such as
in transforms modules for plpython.

This eliminates many seconds of test duration and the cause to invoke
"rm -rf", which is typically unavailable on Windows.

Michael Paquier and Noah Misch

Commit c67a86f7 caught most of these,
but this negative test escaped notice.  The test did pass, for the wrong
reason, under affected configurations.

Michael Paquier

coerce_type() has local variables named targetTypeId, baseTypeId, and
targetType.  targetType has been the Type structure for baseTypeId, so
rename it to baseType.

PORTNAME isn't set until the global makefiles have been included.

Apparently, looking for an appropriately named file doesn't work on some
older versions, so put the back the explicit platform detection.

Combine the two places that set CPPFLAGS into one.  Also, some settings
should be restricted to Windows only.  More precisely, -Wno-comment is
a GCC-only option, but Windows in a makefile implies GCC at the moment.

Also, since -Wno-comment is more properly a preprocessor option, move it
to CPPFLAGS to simplify things a bit.

For building PL/Perl, PL/Python, and PL/Tcl, we need a shared library of
libperl, libpython, and libtcl, respectively.  Previously, this was
checked in the makefiles, skipping the PL build with a warning if no
shared library was available.  Now this is checked in configure, with an
error if no shared library is available.

The previous situation arose because in the olden days, the configure
options --with-perl, --with-python, and --with-tcl controlled whether
frontend interfaces for those languages would be built.  The procedural
languages were added later, and shared libraries were often not
available in the beginning.  So it was decided skip the builds of the
procedural languages in those cases.  The frontend interfaces have since
been removed from the tree, and shared libraries are now available most
of the time, so that setup makes much less sense now.

Also, the new setup allows contrib modules and pgxs users to rely on the
respective PLs being available based on configure flags.

This involves moving perl's CORE library to the end of the include list,
and adding other compilation settings that plperl uses. This won't
completely fix the breakage currently being seen by gcc builds on
Windows, but it will let the build get further, and should be wholly
benign, if not beneficial, on *nix.

pg_dump turns tables into views using a method that was not setting
pg_class.relreplident properly.

Patch by Marko Tiikkaja

Backpatch through 9.4

Tom Lane pointed out that this wasn't done, and asked whether that was
intentional.  Subsequent discussion was in favor of making the change,
so here we go.