Produce a NOTICE when the label already exists, for consistency with other
CREATE IF NOT EXISTS commands.  Also, fix the code so it produces something
more user-friendly than an index violation when the label already exists.
This not incidentally enables making a regression test that the previous
patch didn't make for fear of exposing an unpredictable OID in the results.
Also some wordsmithing on the documentation.

If the label is already in the enum the statement becomes a no-op.
This will reduce the pain that comes from our not allowing this
operation inside a transaction block.

Andrew Dunstan, reviewed by Tom Lane and Magnus Hagander.

The previous scheme had bugs in some corner cases involving tables that had
been renamed since a view was made.  This could result in dumped views that
failed to reload or reloaded incorrectly, as seen in bug #7553 from Lloyd
Albin, as well as in some pgsql-hackers discussion back in January.  Also,
its behavior for printing EXPLAIN plans was sometimes confusing because of
willingness to use the same alias for multiple RTEs (it was Ashutosh
Bapat's complaint about that aspect that started the January thread).

To fix, ensure that each RTE in the query has a unique unqualified alias,
by modifying the alias if necessary (we add "_" and digits as needed to
create a non-conflicting name).  Then we can just print its variables with
that alias, avoiding the confusing and bug-prone scheme of sometimes
schema-qualifying variable names.  In EXPLAIN, it proves to be expedient to
take the further step of only assigning such aliases to RTEs that are
actually referenced in the query, since the planner has a habit of
generating extra RTEs with the same alias in situations such as
inheritance-tree expansion.

Although this fixes a bug of very long standing, I'm hesitant to back-patch
such a noticeable behavioral change.  My experiments while creating a
regression test convinced me that actually incorrect output (as opposed to
confusing output) occurs only in very narrow cases, which is backed up by
the lack of previous complaints from the field.  So we may be better off
living with it in released branches; and in any case it'd be smart to let
this ripen awhile in HEAD before we consider back-patching it.

Similar changes were done to pg_hba.conf earlier already, this commit makes
pg_ident.conf to behave the same as pg_hba.conf.

This has two user-visible effects. First, if pg_ident.conf contains multiple
errors, the whole file is parsed at postmaster startup time and all the
errors are immediately reported. Before this patch, the file was parsed and
the errors were reported only when someone tries to connect using an
authentication method that uses the file, and the parsing stopped on first
error. Second, if you SIGHUP to reload the config files, and the new
pg_ident.conf file contains an error, the error is logged but the old file
stays in effect.

Also, regular expressions in pg_ident.conf are now compiled only once when
the file is loaded, rather than every time the a user is authenticated. That
should speed up authentication if you have a lot of regexps in the file.

Amit Kapila

load_hba and load_ident load stuff in a separate memory context nowadays,
not in the current memory context.

These calls were removed in commit 4240e429
as part of a general refactoring and improvement of DDL locking.  However,
there's a problem not solved by the rewrite, which is that GRANT/REVOKE
update pg_class.relacl without taking any particular lock on the target
table as such.  If another backend fails to do AcceptInvalidationMessages,
it won't notice a recently-committed change in ACLs.  Bug #7557 from Piotr
Czachur demonstrates that there's at least one code path in 9.2.0 in which
a command fails to do any AcceptInvalidationMessages calls at all, if the
current transaction already holds all the locks it will need.

Since we're hard up against the release deadline for 9.2.1, fix this by
putting back the AcceptInvalidationMessages calls in heap_openrv and
heap_openrv_extended, thereby restoring the historical behavior in this
area.  We ought to look for a more elegant and perhaps more bulletproof
solution, but there's no time for that right now.

DST law changes in Fiji.

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

bug #7548 from Reinhard Max

In commit 9e8da0f7, I improved btree
to handle ScalarArrayOpExpr quals natively, so that constructs like
"indexedcol IN (list)" could be supported by index-only scans.  Using
such a qual results in multiple scans of the index, under-the-hood.
I went to some lengths to ensure that this still produces rows in index
order ... but I failed to recognize that if a higher-order index column
is lacking an equality constraint, rescans can produce out-of-order
data from that column.  Tweak the planner to not expect sorted output
in that case.  Per trouble report from Robert McGehee.

Not sure how we missed this case, but we did.  Per bug #7551 from
Diego de Lima.

It prevented the libpq directory from being installable by itself.

Somewhere along the line, somebody decided to remove all trace of this
notation from the documentation text.  It was still in the command syntax
synopses, or at least some of them, but with no indication what it meant.
This will not do, as evidenced by the confusion apparent in bug #7543;
even if the notation is now unnecessary, people will find it in legacy
SQL code and need to know what it does.

Currently, we are making mangled copies of plpython/{expected,sql} to
plpython/python3/{expected,sql}, and run the tests in
plpython/python3.  This has the disadvantage that the regression.diffs
file, if any, ends up in plpython/python3, which is not the normal
location.  If we instead make the mangled copies in
plpython/{expected,sql}/python3/, we can run the tests from the normal
directory, regression.diffs ends up the normal place, and the
pg_regress invocation also becomes a lot simpler.  It's also more
obvious at run time what's going on, because the tests end up being
named "python3/something" in the test output.

Some experimentation with examples similar to bug #7539 has convinced me
that indxpath.c's original implementation of parameterized-path generation
was several bricks shy of a load.  In general, if we are relying on a
particular outer rel or set of outer rels for a parameterized path, the
path should use every indexable join clause that's available from that rel
or rels.  Any join clauses that get left out of the indexqual will end up
getting applied as plain filter quals (qpquals), and that's generally a
significant loser compared to having the index AM enforce them.  (This is
particularly true with btree, which can skip the index scan entirely if
it can see that the given indexquals are mutually contradictory.)  The
original heuristics failed to ensure this, though, and were overly
complicated anyway.  Rewrite to make the code explicitly identify each
useful set of outer rels and then select all applicable join clauses for
each one.  The one plan that changes in the regression tests is in fact
for the better according to the planner's cost estimates.

(Note: this is not a correctness issue but just a matter of plan quality.
I don't yet know what is going on in bug #7539, but I don't expect this
change to fix that.)

Recovery code documents clearly that a shutdown checkpoint is executed at
end of recovery - a shutdown checkpoint WAL record is written but the buffer
manager had been altered to treat end of recovery as a normal checkpoint.
This bug exacerbates the bufmgr relpersistence bug.

Bug spotted by Andres Freund, patch by me.

The documentation mentioned setting autovacuum_freeze_max_age to
"its maximum allowed value of a little less than two billion".
This led to a post asking about the exact maximum allowed value,
which is precisely two billion, not "a little less".

Based on question by Radovan Jablonovsky.  Backpatch to 8.3.

Looks like the correct size of DOS-ified tenk.data is 680800 not 680801.
(I got the latter from a version of unix2dos that appends a trailing ^Z,
which evidently is not git's practice.)

- ALTER DOMAIN ... DROP/RENAME/VALIDATE CONSTRAINT
- ALTER TABLE ... RENAME/VALIDATE CONSTRAINT
- COMMENT ON CONSTRAINT
- SET CONSTRAINTS

The idea here is to provide a more easily diagnosable failure diff when
the problem is that tenk.data has been DOS-ified, as I believe to be
happening currently on buildfarm member hamerkop.  Per suggestion from
Magnus Hagander.

Also, sync output/largeobject_1.source with current regression test.
Failure to do that in commit 3a0e4d36
turns out to be the real reason that hamerkop has been complaining.

Given what we now know about the cause of this bug, it seems like it'd
be a real good idea to include it in the plperl regression tests, so as
to catch any platform-specific cases where the code gets misoptimized.

This can result in buffers failing to be properly flushed at
checkpoint time, leading to data loss.

Report, diagnosis, and patch by Jeff Davis.

This at least saves some palloc overhead, and should furthermore reduce
the risk of anything going wrong, eg somebody resetting the context the
current_call_data record was in.

In commit 1bc16a94 I added a minor
optimization to drop the component variables of a GROUP BY expression from
the target list computed at the aggregation level of a query, if those Vars
weren't referenced elsewhere in the tlist.  However, I overlooked that the
window-function planning code would deconstruct such expressions and thus
need to have access to their component variables.  Fix it to not do that.

While at it, I removed the distinction between volatile and nonvolatile
window partition/order expressions: the code now computes all of them
at the aggregation level.  This saves a relatively expensive check for
volatility, and it's unclear that the resulting plan isn't better anyway.

Per bug #7535 from Louis-David Mitterrand.  Back-patch to 9.2.

Backpatch to 9.2.

Etsuro Fujit

Backpatch to 9.2.

I made multiple errors in commit 97532f7c,
stemming mostly from failure to think about the available frequency data
as being element frequencies not value frequencies (so that occurrences of
different elements are not mutually exclusive).  This led to sillinesses
such as estimating that "word" would match more rows than "word:*".

The choice to clamp to a minimum estimate of DEFAULT_TS_MATCH_SEL also
seems pretty ill-considered in hindsight, as it would frequently result in
an estimate much larger than the available data suggests.  We do need some
sort of clamp, since a pattern not matching any of the MCELEMs probably
still needs a selectivity estimate of more than zero.  I chose instead to
clamp to at least what a non-MCELEM word would be estimated as, preserving
the property that "word:*" doesn't get an estimate less than plain "word",
whether or not the word appears in MCELEM.

Per investigation of a gripe from Bill Martin, though I suspect that his
example case actually isn't even reaching the erroneous code.

Back-patch to 9.1 where this code was introduced.

Dan Scott

This follows recent addition of Windows/Mingw testing.
Backpatch to Release 9.2 so we can get some buildfarm testing
going.

validate_plperl_function() supposed that it could free an old
plperl_proc_desc struct immediately upon detecting that it was stale.
However, if a plperl function is called recursively, this could result
in deleting the struct out from under an outer invocation, leading to
misbehavior or crashes.  Add a simple reference-count mechanism to
ensure that such structs are freed only when the last reference goes
away.

Per investigation of bug #7516 from Marko Tiikkaja.  I am not certain
that this error explains his report, because he says he didn't have
any recursive calls --- but it's hard to see how else it could have
crashed right there.  In any case, this definitely fixes some problems
in the area.

Back-patch to all active branches.

Investigation shows that some intermittent build failures in ecpg are the
result of a gmake bug that was reported quite some time ago:
http://savannah.gnu.org/bugs/?30653

Preventing parallel builds of the ecpg subdirectories seems to dodge the
bug.  Per yesterday's pgsql-hackers discussion, there are some other things
in the subdirectory makefiles that seem rather unsafe for parallel builds
too, but there's little point in fixing them as long as we have to work
around a make bug.

Back-patch to 9.1; parallel builds weren't very well supported before
that anyway.

Commit 2cfb1c6f fixed some issues caused
by Python 3.3 choosing to iterate through dict entries in a different order
than before.  But here's another one: the test cases adjusted here made two
bad entries in a dict and expected the one complained of would always be
the same.

Possibly this should be back-patched further than 9.2, but there seems
little point unless the earlier fix is too.

Create an internal function pqDropConnection that does the physical socket
close and cleans up closely-associated state.  This removes a bunch of ad
hoc, not always consistent closure code.  The ulterior motive is to have a
single place to wait for a spawned child backend to exit, but this seems
like good cleanup even if that never happens.

I went back and forth on whether to include "conn->status = CONNECTION_BAD"
in pqDropConnection's actions, but for the moment decided not to.  Only a
minority of the call sites actually want that, and in any case it's
arguable that conn->status is slightly higher-level state, and thus not
part of this function's purview.

Etsuro Fujita

This affects initdb, clusterdb, reindexdb, and vacuumdb in master
and 9.2; in earlier branches, only initdb is affected.

This fix removes an unnecessary incompatibility with the old behavior of
the unix_socket_directory parameter.  Since pathnames with embedded spaces
are fairly popular on some platforms, the incompatibility could be
significant in practice.  We'll still strip unquoted leading/trailing
spaces, however.

No docs update since the documentation already implied that it worked
like this.

Per bug #7514 from Murray Cumming.