Back-patch to 9.4, like the feature's removal.

Apart from ignoring "hostaddr" set to the empty string, this behaves
identically to its predecessor.  Back-patch to 9.4, where the original
commit first appeared.

Reviewed by Fujii Masao.

This reverts commit 9f80f483.  The
function returned the raw value of a connection parameter, a task served
by PQconninfo().  The next commit will reimplement the psql \conninfo
change that way.  Back-patch to 9.4, where that commit first appeared.

The original definitions were leaving no room for cross-type operators,
so queries that compared a column of one type against something of a
different type were not taking advantage of the index.  Fix by making
the opfamilies more like the ones for Btree, and include a few
cross-type operator classes.

Catalog version bumped.

Per complaints from Hubert Lubaczewski, Mark Wong, Heikki Linnakangas.

Multixacts are now maintained during recovery, but the README didn't get
the memo.  Backpatch to 9.3, where the divergence was introduced.

This patch adds a function that replaces a bms_membership() test followed
by a bms_singleton_member() call, performing both the test and the
extraction of a singleton set's member in one scan of the bitmapset.
The performance advantage over the old way is probably minimal in current
usage, but it seems worthwhile on notational grounds anyway.

David Rowley

This patch adds a way of iterating through the members of a bitmapset
nondestructively, unlike the old way with bms_first_member().  While
bms_next_member() is very slightly slower than bms_first_member()
(at least for typical-size bitmapsets), eliminating the need to palloc
and pfree a temporary copy of the target bitmapset is a significant win.
So this method should be preferred in all cases where a temporary copy
would be necessary.

Tom Lane, with suggestions from Dean Rasheed and David Rowley

This function was initially coded on the assumption that it would not be
performance-critical, but that turns out to be wrong in workloads that
are heavily dependent on the speed of plpgsql functions.  Speed it up by
hard-coding the comparison rules, thereby avoiding palloc/pfree traffic
from creating and immediately freeing an OverrideSearchPath object.
Per report from Scott Marlowe.

Previously, if the typcache had for example tried and failed to find a hash
opclass for a given data type, it would nonetheless repeat the unsuccessful
catalog lookup each time it was asked again.  This can lead to a
significant amount of useless bufmgr traffic, as in a recent report from
Scott Marlowe.  Like the catalog caches, typcache should be able to cache
negative results.  This patch arranges that by making use of separate flag
bits to remember whether a particular item has been looked up, rather than
treating a zero OID as an indicator that no lookup has been done.

Also, install a credible invalidation mechanism, namely watching for inval
events in pg_opclass.  The sole advantage of the lack of negative caching
was that the code would cope if operators or opclasses got added for a type
mid-session; to preserve that behavior we have to be able to invalidate
stale lookup results.  Updates in pg_opclass should be pretty rare in
production systems, so it seems sufficient to just invalidate all the
dependent data whenever one happens.

Adding proper invalidation also means that this code will now react sanely
if an opclass is dropped mid-session.  Arguably, that's a back-patchable
bug fix, but in view of the lack of complaints from the field I'll refrain
from back-patching.  (Probably, in most cases where an opclass is dropped,
the data type itself is dropped soon after, so that this misfeasance has
no bad consequences.)

Back-patch to 9.4 where ALTER TABLE ALTER CONSTRAINT was added.

Michael Paquier, bug reported by Andrey Lizenko.

InitXLogInsert() cannot be called in a critical section, because it
allocates memory. But CreateCheckPoint() did that, when called for the
end-of-recovery checkpoint by the startup process.

In the passing, fix the scratch space allocation in InitXLogInsert to go to
the right memory context. Also update the comment at InitXLOGAccess, which
hasn't been totally accurate since hot standby was introduced (in a hot
standby backend, InitXLOGAccess isn't called at backend startup).

Reported by Michael Paquier

Previously \watch always ignored the user's \pset null setting.
\pset null setting should be ignored for \d and similar queries.
For those, the code can reasonably have an opinion about what
the presentation should be like, since it knows what SQL query
it's issuing. This argument surely doesn't apply to \watch,
so this commit makes \watch use the user's \pset null setting.

Back-patch to 9.3 where \watch was added.

Back-patch to 9.3 where pg_isready was added.

Mats Erik Andersson

Mark Simonetti reported that libxslt sometimes crashes for him, and that
swapping xslt_process's object-freeing calls around to do them in reverse
order of creation seemed to fix it.  I've not reproduced the crash, but
valgrind clearly shows a reference to already-freed memory, which is
consistent with the idea that shutdown of the xsltTransformContext is
trying to reference the already-freed stylesheet or input document.
With this patch, valgrind is no longer unhappy.

I have an inquiry in to see if this is a libxslt bug or if we're just
abusing the library; but even if it's a library bug, we'd want to adjust
our code so it doesn't fail with unpatched libraries.

Back-patch to all supported branches, because we've been doing this in
the wrong(?) order for a long time.

As pointed out by Robert, we should really have named pg_rowsecurity
pg_policy, as the objects stored in that catalog are policies.  This
patch fixes that and updates the column names to start with 'pol' to
match the new catalog name.

The security consideration for COPY with row level security, also
pointed out by Robert, has also been addressed by remembering and
re-checking the OID of the relation initially referenced during COPY
processing, to make sure it hasn't changed under us by the time we
finish planning out the query which has been built.

Robert and Alvaro also commented on missing OCLASS and OBJECT entries
for POLICY (formerly ROWSECURITY or POLICY, depending) in various
places.  This patch fixes that too, which also happens to add the
ability to COMMENT on policies.

In passing, attempt to improve the consistency of messages, comments,
and documentation as well.  This removes various incarnations of
'row-security', 'row-level security', 'Row-security', etc, in favor
of 'policy', 'row level security' or 'row_security' as appropriate.

Happy Thanksgiving!

It was added in commit efc16ea5, but never defined.

Report by Heikki Linnakangas.

In passing, add an Assert defending the presumption that bytes_left
is positive to start with.  (I'm not exactly convinced that using an
unsigned type was such a bright thing here, but let's at least do
this much.)

action_at_recovery_target = pause | promote | shutdown

Petr Jelinek

Reviewed by Muhammad Asif Naeem, Fujji Masao and
Simon Riggs

Add a bit of context sensitivity to plpgsql_yylex() so that it can
recognize when the word it is looking at is the first word of a new
statement, and if so whether it is the target of an assignment statement.
When we are at start of statement and it's not an assignment, we can
prefer recognizing unreserved keywords over recognizing variable names,
thereby allowing most statements' initial keywords to be demoted from
reserved to unreserved status.  This is rather useful already (there are
15 such words that get demoted here), and what's more to the point is
that future patches proposing to add new plpgsql statements can avoid
objections about having to add new reserved words.

The keywords BEGIN, DECLARE, FOR, FOREACH, LOOP, WHILE need to remain
reserved because they can be preceded by block labels, and the logic
added here doesn't understand about block labels.  In principle we
could probably fix that, but it would take more than one token of
lookback and the benefit doesn't seem worth extra complexity.

Also note I didn't de-reserve EXECUTE, because it is used in more places
than just statement start.  It's possible it could be de-reserved with
more work, but that would be an independent fix.

In passing, also de-reserve COLLATE and DEFAULT, which shouldn't have
been reserved in the first place since they only need to be recognized
within DECLARE sections.

These cases formerly failed with errors about "could not find array type
for data type".  Now they yield arrays of the same element type and one
higher dimension.

The implementation involves creating functions with API similar to the
existing accumArrayResult() family.  I (tgl) also extended the base family
by adding an initArrayResult() function, which allows callers to avoid
special-casing the zero-inputs case if they just want an empty array as
result.  (Not all do, so the previous calling convention remains valid.)
This allowed simplifying some existing code in xml.c and plperl.c.

Ali Akbar, reviewed by Pavel Stehule, significantly modified by me

Per discussion with Tom and Andrew, 64bit integers are no longer a
problem for the catalogs, so go ahead and add the mapping from the C
int64 type to the int8 SQL identification to allow using them.

Patch by Adam Brightwell

The old method of appending options to the connection string didn't work if
the primary_conninfo was a postgres:// style URI, instead of a traditional
connection string. Use PQconnectdbParams instead.

Alex Shulgin

If the "dbname" attribute in PQconnectDBParams contained a connection string
or URI (and expand_dbname = TRUE), the database name from the connection
string could not be overridden by a subsequent "dbname" keyword in the
array. That was not intentional; all other options can be overridden.
Furthermore, any subsequent "dbname" caused the connection string from the
first dbname value to be processed again, overriding any values for the same
options that were given between the connection string and the second dbname
option.

In the passing, clarify in the docs that only the first dbname option in the
array is parsed as a connection string.

Alex Shulgin. Backpatch to all supported versions.

In the regression tests, when doing cascaded drops, we need to suppress
the notices from DROP CASCADE or there can be transient regression
failures as the order of drops can depend on the physical row order in
pg_depend.

Report and fix suggestion from Tom.

An out-of-memory in most of these would lead to strange behavior, like
connecting to a different database than intended, but some would lead to
an outright segfault.

Alex Shulgin and me. Backpatch to all supported versions.

Code that check the flag no longer need #ifdef's, which is more convenient.
In particular, makes it easier to write extensions that depend on it.

In the passing, modify sslinfo's ssl_is_used function to check ssl_in_use
instead of the OpenSSL specific 'ssl' pointer. It doesn't make any
difference currently, as sslinfo is only compiled when built with OpenSSL,
but seems cleaner anyway.

This is further infrastructure for parallelism.

Amit Khandekar, Noah Misch, Robert Haas

This gives an overview of what Lehman & Yao's paper is all about, so that
you can understand the rest of the README without having to read the paper.

Per discussion with Peter Geoghegan and others.

Add a new XLOG_FPI_FOR_HINT record type, and use that for full-page images
generated for hint bit updates, when checksums are enabled. The new record
type is replayed exactly the same as XLOG_FPI, but allows them to be tallied
separately e.g. in pg_xlogdump.

There may once have been a reason for the intermediate proc_stmts
production in the plpgsql grammar, but it isn't doing anything useful
anymore, so let's collapse it into proc_sect.  Saves some code and
probably a small number of nanoseconds per statement list.

In passing, correctly alphabetize keyword lists to match pl_scanner.c;
note that for "rowtype" vs "row_count", pl_scanner.c must sort on the
basis of the lower-case spelling.

Noted while fooling with a patch to de-reserve more plpgsql keywords.

This eliminates gobs of "unrecognized format function type" warnings
under MinGW compilers predating GCC 4.4.

The locution "EXISTS(SELECT ... LIMIT 1)" seems to be rather common among
people who don't realize that the database already performs optimizations
equivalent to putting LIMIT 1 in the sub-select.  Unfortunately, this was
actually making things worse, because it prevented us from optimizing such
EXISTS clauses into semi or anti joins.  Teach simplify_EXISTS_query() to
suppress constant-positive LIMIT clauses.  That fixes the semi/anti-join
case, and may help marginally even for cases that have to be left as
sub-SELECTs.

Marti Raudsepp, reviewed by David Rowley

postgres_fdw would send query conditions involving system columns to the
remote server, even though it makes no effort to ensure that system
columns other than CTID match what the remote side thinks.  tableoid,
in particular, probably won't match and might have some use in queries.
Hence, prevent sending conditions that include non-CTID system columns.

Also, create_foreignscan_plan neglected to check local restriction
conditions while determining whether to set fsSystemCol for a foreign
scan plan node.  This again would bollix the results for queries that
test a foreign table's tableoid.

Back-patch the first fix to 9.3 where postgres_fdw was introduced.
Back-patch the second to 9.2.  The code is probably broken in 9.1 as
well, but the patch doesn't apply cleanly there; given the weak state
of support for FDWs in 9.1, it doesn't seem worth fixing.

Etsuro Fujita, reviewed by Ashutosh Bapat, and somewhat modified by me

PSQLexec's error reporting turns out to be too verbose for this case, so
revert to using PQexec instead with minimal error reporting. Prior to
calling PQexec, we call a function that mimics just the echo_hidden
piece of PSQLexec.

Make it work more like FDW plans do: instead of assuming that there are
expressions in a CustomScan plan node that the core code doesn't know
about, insist that all subexpressions that need planner attention be in
a "custom_exprs" list in the Plan representation.  (Of course, the
custom plugin can break the list apart again at executor initialization.)
This lets us revert the parts of the patch that exposed setrefs.c and
subselect.c processing to the outside world.

Also revert the GetSpecialCustomVar stuff in ruleutils.c; that concept
may work in future, but it's far from fully baked right now.

Instead of register_custom_path_provider and a CreateCustomScanPath
callback, let's just provide a standard function hook in set_rel_pathlist.
This is more flexible than what was previously committed, is more like the
usual conventions for planner hooks, and requires less support code in the
core.  We had discussed this design (including centralizing the
set_cheapest() calls) back in March or so, so I'm not sure why it wasn't
done like this already.