Simplify API for initially hooking custom-path providers into the planner.

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.
Rearrange CustomScan API.

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.
Rework echo_hidden for \sf and \ef from commit e4d2817.

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.
Fix mishandling of system columns in FDW queries.

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
Allow simplification of EXISTS() subqueries containing LIMIT.

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
Detect PG_PRINTF_ATTRIBUTE automatically.

This eliminates gobs of "unrecognized format function type" warnings
under MinGW compilers predating GCC 4.4.
Fix memory leaks introduced by commit eca2b9b
Get rid of redundant production in plpgsql grammar.

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.
Distinguish XLOG_FPI records generated for hint-bit updates.

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.
Add a few paragraphs to B-tree README explaining L&Y algorithm.

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 infrastructure to save and restore GUC values.

This is further infrastructure for parallelism.

Amit Khandekar, Noah Misch, Robert Haas
Make Port->ssl_in_use available, even when built with !USE_SSL

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.
Check return value of strdup() in libpq connection option parsing.

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.
Suppress DROP CASCADE notices in regression tests

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.
Allow "dbname" from connection string to be overridden in PQconnectDBParams

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.
Allow using connection URI in primary_conninfo.

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
Add int64 -> int8 mapping to genbki

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
Support arrays as input to array_agg() and ARRAY(SELECT ...).

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
De-reserve most statement-introducing keywords in plpgsql.

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.
action_at_recovery_target recovery config option

action_at_recovery_target = pause | promote | shutdown

Petr Jelinek

Reviewed by Muhammad Asif Naeem, Fujji Masao and
Simon Riggs