This includes two new kinds of postmaster processes, walsenders and
walreceiver. Walreceiver is responsible for connecting to the primary server
and streaming WAL to disk, while walsender runs in the primary server and
streams WAL from disk to the client.

Documentation still needs work, but the basics are there. We will probably
pull the replication section to a new chapter later on, as well as the
sections describing file-based replication. But let's do that as a separate
patch, so that it's easier to see what has been added/changed. This patch
also adds a new section to the chapter about FE/BE protocol, documenting the
protocol used by walsender/walreceivxer.

Bump catalog version because of two new functions,
pg_last_xlog_receive_location() and pg_last_xlog_replay_location(), for
monitoring the progress of replication.

Fujii Masao, with additional hacking by me

of this are to centralise the conflict code to allow further change,
as well as to allow passing through the full reason for the conflict
through to the conflicting backends. Backend state alters how we
can handle different types of conflict so this is now required.
As originally suggested by Heikki, no longer optional.

rather than trying to implement the equivalent logic by hand.  The motivation
for the original coding appears to have been to check with the effective uid's
permissions not the real uid's; but there is no longer any difference, because
we don't run the postmaster setuid (indeed, main.c enforces that they're the
same).  Using access() means we will get it right in situations the original
coding failed to handle, such as ACL-based permissions.  Besides it's a lot
shorter, cleaner, and more thread-safe.  Per bug #5275 from James Bellinger.

underlying catalog not only the index itself.  Otherwise, if the cache
load process touches the catalog (which will happen for many though not
all of these indexes), we are locking index before parent table, which can
result in a deadlock against processes that are trying to lock them in the
normal order.  Per today's failure on buildfarm member gothic_moth; it's
surprising the problem hadn't been identified before.

Back-patch to 8.2.  Earlier releases didn't have the issue because they
didn't try to lock these indexes during load (instead assuming that they
couldn't change schema at all during multiuser operation).

especially not ROLLBACK.  ROLLBACK might need to be executed in an already
aborted transaction, when there is no safe way to revalidate the plan.  But
in general there's no point in marking utility statements invalid, since
they have no plans in the normal sense of the word; so we might as well
work a bit harder here to avoid future revalidation cycles.

Back-patch to 8.4, where the bug was introduced.

Given that undefined types are handled as character strings anyway the type
translation function can simply return the correcponding ECPGt_char type.

For non-SQL3 types ecpg used to return -Oid. This will break if there are
enough Oids to fill the namespace. Therefore we play it safe and return 0 if
there is no Oid->SQL3 tyoe mapping available.

in the parameter array.  Noted while experimenting with an example
from Pavel.  This wouldn't come up in normal use, but it ought to honor
the specification that a parameter array can have unused slots.

Updated to reflect building with Visual Studio 2008, with just the
Platform SDK, and for 64-bit Windows.

occurring during a reload, such as query-cancel.  Instead of zeroing out
an existing relcache entry and rebuilding it in place, build a new relcache
entry, then swap its contents with the old one, then free the new entry.
This avoids problems with code believing that a previously obtained pointer
to a cache entry must still reference a valid entry, as seen in recent
failures on buildfarm member jaguar.  (jaguar is using CLOBBER_CACHE_ALWAYS
which raises the probability of failure substantially, but the problem
could occur in the field without that.)  The previous design was okay
when it was made, but subtransactions and the ResourceOwner mechanism
make it unsafe now.

Also, make more use of the already existing rd_isvalid flag, so that we
remember that the entry requires rebuilding even if the first attempt fails.

Back-patch as far as 8.2.  Prior versions have enough issues around relcache
reload anyway (due to inadequate locking) that fixing this one doesn't seem
worthwhile.

Removed ecpg Changelog file that was only there for historical reasons and isn't actively used anymore.

can upgrade clusters without renaming the tablespace directories.  New
directory structure format is, e.g.:

	$PGDATA/pg_tblspc/20981/PG_8.5_201001061/719849/83292814

(An Assert is no substitute for thinking clearly :-()

Minor style kibitzing too.

Per report from Robert Treat.

settings to prevent the postmaster from being OOM-killed on Linux systems.

Alex Hunsaker and Tom Lane

rowtype contains dropped columns.  Sometimes the input tuple will be formed
from a select targetlist in which dropped columns are filled with a NULL
of an arbitrary type (the planner typically uses INT4, since it can't tell
what type the dropped column really was).  So we need to relax the rowtype
compatibility check to not insist on physical compatibility if the actual
column value is NULL.

In principle we might need to do this for functions returning composite
types, too (see tupledesc_match()).  In practice there doesn't seem to be
a bug there, probably because the function will be using the same cached
rowtype descriptor as the caller.  Fixing that code path would require
significant rearrangement, so I left it alone for now.

Per complaint from Filip Rembialkowski.

generic syntax error, when seeing "foo := something" and foo isn't recognized.
This buys back most of the helpfulness discarded in my previous patch by not
throwing errors when a qualified name appears to match a row variable but the
last component doesn't match any field of the row.  It covers other cases
where our error messages left something to be desired, too.

field references in SQL expressions to have RECFIELD datum-array entries at
parse time.  If it turns out that the reference is actually to a SQL column,
the RECFIELD entry is useless, but it costs little.  This allows us to get rid
of the previous use of FieldSelect applied to a whole-row Param for the record
variable; which was not only slower than a direct RECFIELD reference, but
failed for references to system columns of a trigger's NEW or OLD record.
Per report and fix suggestion from Dean Rasheed.

Adding missing docs for previous Hot Standby patch.

pginstaller isn't used anymore, in favor of the one-click installers.
Make it clear that we support Windows 2000 and newer with the native
port, instead of first saying we support NT4 and then saying we don't.

Previously we only cancelled sessions that were in-transaction.

Simple fix is to just cancel all sessions without waiting. Doing
it this way avoids complicating common code paths, which would
not be worth the trouble to cover this rare case.

Problem report and fix by Andres Freund, edited somewhat by me

This silences some warnings on Win64. Not using the proper SOCKET datatype
was actually wrong on Win32 as well, but didn't cause any warnings there.

Also create define PGINVALID_SOCKET to indicate an invalid/non-existing
socket, instead of using a hardcoded -1 value.

Previously, fastgetattr() and heap_getattr() tested their fourth argument
against a null pointer, but any attempt to use them with a literal-NULL
fourth argument evaluated to *(void *)0, resulting in a compiler error.
Remove these NULL tests to avoid leading future readers of this code to
believe that this has a chance of working.  Also clean up related legacy
code in nocachegetattr(), heap_getsysattr(), and nocache_index_getattr().

The new coding standard is that any code which calls a getattr-type
function or macro which takes an isnull argument MUST pass a valid
boolean pointer.  Per discussion with Bruce Momjian, Tom Lane, Alvaro
Herrera.

This should have been part of the original tablespace-options patch, but I
overlooked the need to update this portion of the documentation.

extract a system column, and remove a couple of lines that are useless
in light of the fact that we aren't ever going to support this case.  There
isn't much point in trying to make this work because a tuple Datum does
not carry many of the system columns.  Per experimentation with a case
reported by Dean Rasheed; we'll have to fix his problem somewhere else.

deletion, so that we attempt to unlink the correct filepath. unlink()
errors are ignorable there, so lack of a DatabasePath initialization step
did not cause visible problems until a related bug showed up on Solaris.

Code refactored from xact_redo_commit() to
ProcessCommittedInvalidationMessages() in inval.c. Recovery may replay
shared invalidation messages for many databases, so we cannot
SetDatabasePath() once as we do in normal backends. Read the databaseid
from the shared invalidation messages, then set DatabasePath
temporarily before calling RelationCacheInitFileInvalidate().

Problem report by Robert Treat, analysis and fix by me.

The latter are only run if the platform can run both interpreters in the
same backend.

- Changed MULTIPLICITY check from runtime to compiletime.
    No loads the large Config module.
- Changed plperl_init_interp() to return new interp
    and not alter the global interp_state
- Moved plperl_safe_init() call into check_interp().
- Removed plperl_safe_init_done state variable
    as interp_state now covers that role.
- Changed plperl_create_sub() to take a plperl_proc_desc argument.
- Simplified return value handling in plperl_create_sub.
- Changed perl.com link in the docs to perl.org and tweaked
    wording to clarify that require, not use, is what's blocked.
- Moved perl code in large multi-line C string literal macros
    out to plc_*.pl files.
- Added a test2macro.pl utility to convert the plc_*.pl files to
    macros in a perlchunks.h file which is #included
- Simplifed plperl_safe_init() slightly
- Optimized pg_verifymbstr calls to avoid unneeded strlen()s.

Patch from Tim Bunce, with minor editing from me.

someone else has just updated it, we have to set priorXmax to that tuple's
xmax (ie, the XID of the other xact that updated it) before looping back to
examine the next tuple.  Obviously, the next tuple in the update chain should
have that XID as its xmin, not the same xmin as the preceding tuple that we
had been trying to lock.  The mismatch would cause the EvalPlanQual logic to
decide that the tuple chain ended in a deletion, when actually there was a
live tuple that should have been found.

I inserted this error when recently adding logic to EvalPlanQual to make it
lock tuples before returning them (as opposed to the old method in which the
lock would occur much later, causing a great deal of work to be wasted if we
only then discover someone else updated it).  Sigh.  Per today's report from
Takahiro Itagaki of inconsistent results during pgbench runs.

This uses the same infrastructure with EXPLAIN BUFFERS to support
{shared|local}_blks_{hit|read|written} andtemp_blks_{read|written}
columns in the pg_stat_statements view. The dumped file format
also updated.

Thanks to Robert Haas for the review.

as required by SQL standard.