module and teach PREPARE and protocol-level prepared statements to use it.
In service of this, rearrange utility-statement processing so that parse
analysis does not assume table schemas can't change before execution for
utility statements (necessary because we don't attempt to re-acquire locks
for utility statements when reusing a stored plan).  This requires some
refactoring of the ProcessUtility API, but it ends up cleaner anyway,
for instance we can get rid of the QueryContext global.

Still to do: fix up SPI and related code to use the plan cache; I'm tempted to
try to make SQL functions use it too.  Also, there are at least some aspects
of system state that we want to ensure remain the same during a replan as in
the original processing; search_path certainly ought to behave that way for
instance, and perhaps there are others.

continuously, and requests vacuum runs of "autovacuum workers" to postmaster.
The workers do the actual vacuum work.  This allows for future improvements,
like allowing multiple autovacuum jobs running in parallel.

For now, the code keeps the original behavior of having a single autovac
process at any time by sleeping until the previous worker has finished.

back-stamped for this.

in PITR scenarios.  We now WAL-log the replacement of old XIDs with
FrozenTransactionId, so that such replacement is guaranteed to propagate to
PITR slave databases.  Also, rather than relying on hint-bit updates to be
preserved, pg_clog is not truncated until all instances of an XID are known to
have been replaced by FrozenTransactionId.  Add new GUC variables and
pg_autovacuum columns to allow management of the freezing policy, so that
users can trade off the size of pg_clog against the amount of freezing work
done.  Revise the already-existing code that forces autovacuum of tables
approaching the wraparound point to make it more bulletproof; also, revise the
autovacuum logic so that anti-wraparound vacuuming is done per-table rather
than per-database.  initdb forced because of changes in pg_class, pg_database,
and pg_autovacuum catalogs.  Heikki Linnakangas, Simon Riggs, and Tom Lane.

contrib functionality.  Along the way, remove the USER_LOCKS configuration
symbol, since it no longer makes any sense to try to compile that out.
No user documentation yet ... mmoncure has promised to write some.
Thanks to Abhijit Menon-Sen for creating a first draft to work from.

Strip unused include files out unused include files, and add needed
includes to C files.

The next step is to remove unused include files in C files.

it's not necessary to have three separate calls anymore.  This patch also
fixes things so we don't try to read pg_internal.init until after we've
obtained lock on the target database; which was fairly harmless, but it's
certainly cleaner this way.

The former approach used ExclusiveLock on pg_database, which being a
cluster-wide lock meant only one of these operations could proceed at
a time; worse, it also blocked all incoming connections in ReverifyMyDatabase.
Now that we have LockSharedObject(), we can use locks of different types
applied to databases considered as objects.  This allows much more
flexible management of the interlocking: two CREATE DATABASEs need not
block each other, and need not block connections except to the template
database being used.  Similarly DROP DATABASE doesn't block unrelated
operations.  The locking used in flatfiles.c is also much narrower in
scope than before.  Per recent proposal.

in various places that were previously doing ad hoc pg_database searches.
This may speed up database-related privilege checks a little bit, but
the main motivation is to eliminate the performance reason for having
ReverifyMyDatabase do such a lot of stuff (viz, avoiding repeat scans
of pg_database during backend startup).  The locking reason for having
that routine is about to go away, and it'd be good to have the option
to break it up.

CONNECTION, fix a number of places that were missed (eg pg_dump support),
avoid executing an extra search of pg_database during startup.

Gevik Babakhani

This commit doesn't make much functional change, but it does eliminate some
duplicated code --- for instance, PageIsNew tests are now done inside
XLogReadBuffer rather than by each caller.
The GIST xlog code still needs a lot of love, but I'll worry about that
separately.

an LWLock instead of a spinlock.  This hardly matters on Unix machines
but should improve startup performance on Windows (or any port using
EXEC_BACKEND).  Per previous discussion.

comment line where output as too long, and update typedefs for /lib
directory.  Also fix case where identifiers were used as variable names
in the backend, but as typedefs in ecpg (favor the backend for
indenting).

Backpatch to 8.1.X.

delay and limit, both as global GUCs and as table-specific entries in
pg_autovacuum.  stats_reset_on_server_start is now OFF by default,
but a reset is forced if we did WAL replay.  XID-wrap vacuums do not
ANALYZE, but do FREEZE if it's a template database.  Alvaro Herrera

exit, instead of trying to take shortcuts.  Introduce some additional
shutdown callback routines to eliminate kluges like having ProcKill
be responsible for shutting down the buffer manager.  Ensure that the
order of operations during shutdown is predictable and what you would
expect given the module layering.

This patch also includes preliminary update of pg_dumpall for roles.
Petr Jelinek, with review by Bruce Momjian and Tom Lane.

track shared relations in a separate hashtable, so that operations done
from different databases are counted correctly.  Add proper support for
anti-XID-wraparound vacuuming, even in databases that are never connected
to and so have no stats entries.  Miscellaneous other bug fixes.
Alvaro Herrera, some additional fixes by Tom Lane.

few loose ends to be dealt with, but it seems to work.  Alvaro Herrera,
based on the contrib code by Matthew O'Connor.

chdir into PGDATA and subsequently use relative paths instead of absolute
paths to access all files under PGDATA.  This seems to give a small
performance improvement, and it should make the system more robust
against naive DBAs doing things like moving a database directory that
has a live postmaster in it.  Per recent discussion.

syntactic conflicts, both privilege and role GRANT/REVOKE commands have
to use the same production for scanning the list of tokens that might
eventually turn out to be privileges or role names.  So, change the
existing GRANT/REVOKE code to expect a list of strings not pre-reduced
AclMode values.  Fix a couple other minor issues while at it, such as
InitializeAcl function name conflicting with a Windows system function.

and pg_auth_members.  There are still many loose ends to finish in this
patch (no documentation, no regression tests, no pg_dump support for
instance).  But I'm going to commit it now anyway so that Alvaro can
make some progress on shared dependencies.  The catalog changes should
be pretty much done.

hacking by Alvaro Herrera and Tom Lane.

communication structure, and make it its own module with its own lock.
This should reduce contention at least a little, and it definitely makes
the code seem cleaner.  Per my recent proposal.

is a way to recover from disabling connections to all databases at once.

indexes.  Replace all heap_openr and index_openr calls by heap_open
and index_open.  Remove runtime lookups of catalog OID numbers in
various places.  Remove relcache's support for looking up system
catalogs by name.  Bulky but mostly very boring patch ...

of the local buffer arena for temporary table access.

before we attempt any file deletions in ShutdownPostgres.  Per Tatsuo.

backend exit.  Per report from Bruce.

in favor of looking at the flat file copy of pg_database during backend
startup.  This should finally eliminate the various corner cases in which
backend startup fails unexpectedly because it isn't able to distinguish
live and dead tuples in pg_database.  Simplify locking on pg_database
to be similar to the rules used with pg_shadow and pg_group, and eliminate
FlushRelationBuffers operations that were used only to reduce the odds
of failure of GetRawDatabaseInfo.
initdb forced due to addition of a trigger to pg_database.

the AMI_OVERRIDE flag.  The fact that TransactionLogFetch treats
BootstrapTransactionId as always committed is sufficient to make
bootstrap work, and getting rid of extra tests in heavily used code
paths seems like a win.  The files produced by initdb are demonstrably
the same after this change.

Tag appropriate files for rc3

Also performed an initial run through of upgrading our Copyright date to
extend to 2005 ... first run here was very simple ... change everything
where: grep 1996-2004 && the word 'Copyright' ... scanned through the
generated list with 'less' first, and after, to make sure that I only
picked up the right entries ...

plain SUSET instead.  Also delay processing of options received in
client connection request until after we know if the user is a superuser,
so that SUSET values can be set that way by legitimate superusers.
Per recent discussion.