Fix background workers for EXEC_BACKEND

Commit da07a1e8 was broken for EXEC_BACKEND because I failed to realize
that the MaxBackends recomputation needed to be duplicated by
subprocesses in SubPostmasterMain.  However, instead of having the value
be recomputed at all, it's better to assign the correct value at
postmaster initialization time, and have it be propagated to exec'ed
backends via BackendParameters.

MaxBackends stays as zero until after modules in
shared_preload_libraries have had a chance to register bgworkers, since
the value is going to be untrustworthy till that's finished.

Heikki Linnakangas and Álvaro Herrera
Make sure MaxBackends is always set

Auxiliary and bootstrap processes weren't getting it, causing initdb to
fail completely.
Move tar function headers to pgtar.h

This makes it possible to include them only where they are used, so
we can avoid the conflict of the uid_t and gid_t datatypes that happened
in plperl (since plperl doesn't need the tar functions)
Set MaxBackends only on bootstrap and standalone modes

... not on auxiliary processes.  I managed to overlook the fact that I
had disabled assertions on my HEAD checkout long ago.

Hopefully this will turn the buildfarm green again, and put an end to
today's silliness.
Fix IsUnderPostmaster/EXEC_BACKEND confusion
Adjust a few pg_upgrade functions to return void.

Adjust pg_upgrade page conversion functions (which are not used) to
return void so transfer_all_new_dbs can return void.
Delay reading timeline history file until it's fetched from master.

Streaming replication can fetch any missing timeline history files from the
master, but recovery would read the timeline history file for the target
timeline before reading the checkpoint record, and before walreceiver has
had a chance to fetch it from the master. Delay reading it, and the sanity
checks involving timeline history, until after reading the checkpoint
record.

There is at least one scenario where this makes a difference: if you take
a base backup from a standby server right after a timeline switch, the
WAL segment containing the initial checkpoint record will begin with an
older timeline ID. Without the timeline history file, recovering that file
will fail as the older timeline ID is not recognized to be an ancestor of
the target timeline. If you try to recover from such a backup, using only
streaming replication to fetch the WAL, this patch is required for that to
work.
Tolerate timeline switches while "pg_basebackup -X fetch" is running.

If you take a base backup from a standby server with "pg_basebackup -X
fetch", and the timeline switches while the backup is being taken, the
backup used to fail with an error "requested WAL segment %s has already
been removed". This is because the server-side code that sends over the
required WAL files would not construct the WAL filename with the correct
timeline after a switch.

Fix that by using readdir() to scan pg_xlog for all the WAL segments in the
range, regardless of timeline.

Also, include all timeline history files in the backup, if taken with
"-X fetch". That fixes another related bug: If a timeline switch happened
just before the backup was initiated in a standby, the WAL segment
containing the initial checkpoint record contains WAL from the older
timeline too. Recovery will not accept that without a timeline history file
that lists the older timeline.

Backpatch to 9.2. Versions prior to that were not affected as you could not
take a base backup from a standby before 9.2.
Prevent creation of postmaster's TCP socket during pg_upgrade testing.

On non-Windows machines, we use the Unix socket for connections to test
postmasters, so there is no need to create a TCP socket.  Furthermore,
doing so causes failures due to port conflicts if two builds are carried
out concurrently on one machine.  (If the builds are done in different
chroots, which is standard practice at least in Red Hat distros, there
is no risk of conflict on the Unix socket.)  Suppressing the TCP socket
by setting listen_addresses to empty has long been standard practice
for pg_regress, and pg_upgrade knows about this too ... but pg_upgrade's
test.sh didn't get the memo.

Back-patch to 9.2, and also sync the 9.2 version of the script with HEAD
as much as practical.
Invent a "one-shot" variant of CachedPlans for better performance.

SPI_execute() and related functions create a CachedPlan, execute it once,
and immediately discard it, so that the functionality offered by
plancache.c is of no value in this code path.  And performance measurements
show that the extra data copying and invalidation checking done by
plancache.c slows down simple queries by 10% or more compared to 9.1.
However, enough of the SPI code is shared with functions that do need plan
caching that it seems impractical to bypass plancache.c altogether.
Instead, let's invent a variant version of cached plans that preserves
99% of the API but doesn't offer any of the actual functionality, nor the
overhead.  This puts SPI_execute() performance back on par, or maybe even
slightly better, than it was before.  This change should resolve recent
complaints of performance degradation from Dong Ye, Pavel Stehule, and
others.

By avoiding data copying, this change also reduces the amount of memory
needed to execute many-statement SPI_execute() strings, as for instance in
a recent complaint from Tomas Vondra.

An additional benefit of this change is that multi-statement SPI_execute()
query strings are now processed fully serially, that is we complete
execution of earlier statements before running parse analysis and planning
on following ones.  This eliminates a long-standing POLA violation, in that
DDL that affects the behavior of a later statement will now behave as
expected.

Back-patch to 9.2, since this was a performance regression compared to 9.1.
(In 9.2, place the added struct fields so as to avoid changing the offsets
of existing fields.)

Heikki Linnakangas and Tom Lane
Make some spelling more consistent
doc: Update CREATE FUNCTION compatibility information

Parameter defaults are actually in the SQL standard, while it was
previously claimed they were not.
Revert "PL/Python: Remove workaround for returning booleans in Python <2.3"

This reverts commit be0dfbad3671ed2503a2a661e70b48c5b364e069.

The previous information that Py_RETURN_TRUE and Py_RETURN_FALSE are
supported in Python 2.3 is wrong.  They require Python 2.4.  Update the
comment about that.
PL/Python: Make build on OS X more flexible

The PL/Python build on OS X was previously hardcoded to use the system
installation of Python, ignoring whatever was specified to configure.
Except that it would use the header files from configure, which could
lead to mismatches.  It was not possible to build against a custom
Python installation.

Now, we check in configure how the specified Python installation was
built and use that, supporting framework and non-framework builds.
Centralize single quote escaping in src/port/quotes.c

For code-reuse in upcoming functionality in pg_basebackup.

Zoltan Boszormenyi
Add support for generating minimal recovery.conf when doing base backups

Adds commandline option -R to pg_basebackup that creates a recovery.conf which
enables standby mode using the same parameters that pg_basebackup used to
connect to the master, and writes it into the output directory (or injects it
in the tar file when tar format is used).

Zoltan Boszormenyi, modified by Magnus Hagander, reviewed by Amit Kapila & Fujii Masao
Fix plpython build on older versions of OS X.

Pre-Lion versions of Apple's linker don't allow space between -F and its
argument.  (Snow Leopard is nice enough to tell you that in so many words,
but older versions just fail with very obscure link errors, as seen on
buildfarm member locust for instance.)  Oversight in commit
fc8745070a53469a43ecbf999dc5692a36a649cc.
Add new "-q" logging option (quiet mode) while in initialize mode
(-i), producing only one progress message per 5 seconds along with
elapsed time and estimated remaining time.  Also add elapsed time and
estimated remaining time to the default logging(prints one message
each 100000 rows).
Patch contributed by Tomas Vondra, reviewed by Jeevan Chalke and
Tatsuo Ishii.
Fix incorrect error message when schema-CREATE permission is absent.

Report by me.  Fix by KaiGai Kohei.
Fix a logic bug in pgindent.