This is useful to allow to set GUCs to values that include spaces;
something that wasn't previously possible. The primary case motivating
this is the desire to set default_transaction_isolation to 'repeatable
read' on a per connection basis, but other usecases like seach_path do
also exist.

This introduces a slight backward incompatibility: Previously a \ in
an option value would have been passed on literally, now it'll be
taken as an escape.

The relevant mailing list discussion starts with
20140204125823.GJ12016@awork2.anarazel.de.

This introduces an infrastructure which allows us to specify the units
like ms (milliseconds) in integer relation option, like GUC parameter.
Currently only autovacuum_vacuum_cost_delay reloption can accept
the units.

Reviewed by Michael Paquier

Previously, only a single-byte character was allowed as an
escape. This patch allows it to be a multi-byte character, though it
still must be a single character.

Reviewed by Heikki Linnakangas and Tom Lane.

If SELECT FOR UPDATE NOWAIT tries to lock a tuple that is concurrently
being updated, it might fail to honor its NOWAIT specification and block
instead of raising an error.

Fix by adding a no-wait flag to EvalPlanQualFetch which it can pass down
to heap_lock_tuple; also use it in EvalPlanQualFetch itself to avoid
blocking while waiting for a concurrent transaction.

Authors: Craig Ringer and Thomas Munro, tweaked by Álvaro
http://www.postgresql.org/message-id/51FB6703.9090801@2ndquadrant.com

Per Thomas Munro in the course of his SKIP LOCKED feature submission,
who also provided one of the isolation test specs.

Backpatch to 9.4, because that's as far back as it applies without
conflicts (although the bug goes all the way back).  To that branch also
backpatch Thomas Munro's new NOWAIT test cases, committed in master by
Heikki as commit 9ee16b49 .

This commit also adds the include guards to those header files.

Michael Paquier

In some cases, not all Vars were being correctly marked as having been
modified for updatable security barrier views, which resulted in invalid
plans (eg: when security barrier views were created over top of
inheiritance structures).

In passing, be sure to update both varattno and varonattno, as _equalVar
won't consider the Vars identical otherwise.  This isn't known to cause
any issues with updatable security barrier views, but was noticed as
missing while working on RLS and makes sense to get fixed.

Back-patch to 9.4 where updatable security barrier views were
introduced.

Author: Fabien COELHO <coelho@cri.ensmp.fr>

Spotted by Peter Geoghegan.

Use SECURITY_LOCAL_USERID_CHANGE while building temporary tables;
only escalate to SECURITY_RESTRICTED_OPERATION while potentially
running user-supplied code.  The more secure mode was preventing
temp table creation.  Add regression tests to cover this problem.

This fixes Bug #11208 reported by Bruno Emanuel de Andrade Silva.

Backpatch to 9.4, where the bug was introduced.

Author: David Rowley

Fabrízio de Royes Mello

That allows to run those tests against a postmaster listening on a
nonstandard port without requiring to export PGPORT in postmaster's
environment.

This still doesn't support connecting to a nondefault host without
configuring it in postmaster's environment. That's harder and less
frequently used though. So this is a useful step.

That allows parallel installcheck to succeed inside contrib/. The
output is not particularly pretty unless make's -O option to
synchronize the output is used.

There's other tests, outside contrib, that use a hardcoded,
non-unique, database name. Those prohibit paralell installcheck to be
used across more directories; but that's something for a separate
patch.

Fabrízio de Royes Mello, reviewed by Michael Paquier

Prevent automatic oid assignment when in binary upgrade mode.  Also
throw an error when contrib/pg_upgrade_support functions are called when
not in binary upgrade mode.

This prevent automatically-assigned oids from conflicting with later
pre-assigned oids coming from the old cluster.  It also makes sure oids
are preserved in call important cases.

Done for clarity

Now that 8.3 is not supported, we can use a CTE and not temp tables.
This allows for auto-oid assignment protection in a future patch.

Reverts commits 73d78e11 and
b0488e5c.  Also reverts pg_upgrade
changes.

This trims down the code, and is in preparation for hardening pg_upgrade
against auto-oid assignment.

Add to commit 73d78e11

Also adjust pg_upgrade to not use this method for optional TOAST table
creation.

Patch by Fabrízio de Royes Mello

Report by Pavel Raiskup

Also, remove OID preservation mention, mention non-text dump formats

Backpatch through 9.4

There's no point in setting up a context error callback when doing
conditional lock acquisition, because we never actually wait and so the
user wouldn't be able to see the context message anywhere.  In fact,
this is more in line with what ConditionalXactLockTableWait is doing.

Backpatch to 9.4, where this was added.

The symbol was added by 71901ab6; the original code was introduced by
6868ed74.  Development of both overlapped which is why we apparently
failed to notice.

This is a (very slight) behavior change, so I'm not backpatching this to
9.4 for now, even though the symbol does exist there.

Event triggers want to know the OID of the interesting object created,
which is the main type.  The array created as part of the operation is
just a subsidiary object which is not of much interest.

Other DDL commands are already returning the OID, which is required for
future additional event trigger work.  This is merely making these
commands in line with the rest of utility command support.

Add a succint comment explaining why it's correct to change the
persistence in this way.  Also s/loggedness/persistence/ because native
speakers didn't like the latter term.

Fabrízio and Álvaro

Thomas Munro

Some of the many error messages introduced in 458857cc missed 'FROM
unpackaged'. Also e016b724 and 45ffeb7e forgot to quote extension
version numbers.

Backpatch to 9.1, just like 458857cc which introduced the messages. Do
so because the error messages thrown when the wrong command is copy &
pasted aren't easy to understand.

We also don't track PREPARE, nor do we track planning time in general, so
let's ignore DEALLOCATE as well for consistency.

Backpatch to 9.4, but not further than that. Although it seems unlikely that
anyone is relying on the current behavior, this is a behavioral change.

Fabien Coelho

CheckConstraintFetch() leaked a cstring in the caller's context for each
CHECK constraint expression it copied into the relcache.  Ordinarily that
isn't problematic, but it can be during CLOBBER_CACHE testing because so
many reloads can happen during a single query; so complicate the code
slightly to allow freeing the cstring after use.  Per testing on buildfarm
member barnacle.

This is exactly like the leak fixed in AttrDefaultFetch() by commit
078b2ed2.  (Yes, this time I did look for
other instances of the same coding pattern :-(.)  Like that patch, no
back-patch, since it seems unlikely that there's any problem except under
very artificial test conditions.

BTW, it strikes me that both of these places would require further work
comparable to commit ab8c84db, if we ever
supported defaults or check constraints on system catalogs: they both
assume they are copying into an empty relcache data structure, and that
conceivably wouldn't be the case during recursive reloading of a system
catalog.  This does not seem worth worrying about for the moment, since
there is no near-term prospect of supporting any such thing.  So I'll
just note the possibility for the archives' sake.

Add a note that some options can be specified multiple times to select
multiple objects to restore.  This replaces the somewhat confusing use
of plurals in the option descriptions themselves.

This enables changing permanent (logged) tables to unlogged and
vice-versa.

(Docs for ALTER TABLE / SET TABLESPACE got shuffled in an order that
hopefully makes more sense than the original.)

Author: Fabrízio de Royes Mello
Reviewed by: Christoph Berg, Andres Freund, Thom Brown
Some tweaking by Álvaro Herrera

Cause the path extraction operators to return their lefthand input,
not NULL, if the path array has no elements.  This seems more consistent
since the case ought to correspond to applying the simple extraction
operator (->) zero times.

Cause other corner cases in field/element/path extraction to return NULL
rather than failing.  This behavior is arguably more useful than throwing
an error, since it allows an expression index using these operators to be
built even when not all values in the column are suitable for the
extraction being indexed.  Moreover, we already had multiple
inconsistencies between the path extraction operators and the simple
extraction operators, as well as inconsistencies between the JSON and
JSONB code paths.  Adopt a uniform rule of returning NULL rather than
throwing an error when the JSON input does not have a structure that
permits the request to be satisfied.

Back-patch to 9.4.  Update the release notes to list this as a behavior
change since 9.3.