to assume that the string pointer passed to set_ps_display is good forever.
There's no need to anyway since ps_status.c itself saves the string, and
we already had an API (get_ps_display) to return it.
I believe this explains Jim Nasby's report of intermittent crashes in
elog.c when %i format code is in use in log_line_prefix.
While at it, repair a previously unnoticed problem: on some platforms such as
Darwin, the string returned by get_ps_display was blank-padded to the maximum
length, meaning that lock.c's attempt to append " waiting" to it never worked.

protected data structures and not using a volatile pointer for same.

whether we seem to be running in a uniprocessor or multiprocessor.
The adjustment rules could probably still use further tweaking, but
I'm convinced this should be a win overall.

initialization.  Add spinlocking, fix EXEC_BACKEND unsafeness.

Per request from Marc Munro.

bytes.  This shouldn't make any difference on x86 machines, where the size
happened to be 16 bytes anyway, but on 64-bit machines and machines with
slock_t int or wider, it will speed array indexing and hopefully reduce
SMP cache contention effects.  Per recent experimentation.

definitions on recent Linux systems, per Martin Pitt.

constrained GCC inline version.  Thiemo Seufer, by way of Martin Pitt.

to 'Size' (that is, size_t), and install overflow detection checks in it.
This allows us to remove the former arbitrary restrictions on NBuffers
etc.  It won't make any difference in a 32-bit machine, but in a 64-bit
machine you could theoretically have terabytes of shared buffers.
(How efficiently we could manage 'em remains to be seen.)  Similarly,
num_temp_buffers, work_mem, and maintenance_work_mem can be set above
2Gb on a 64-bit machine.  Original patch from Koichi Suzuki, additional
work by moi.

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.

Original patch by Hans-Juergen Schoenig, revisions by Karel Zak
and Tom Lane.

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

hacking by Alvaro Herrera and Tom Lane.

it is sufficient to track whether a backend holds a lock or not, and
store information about transaction vs. session locks only in the
inside-the-backend LocalLockTable.  Since there can now be but one
PROCLOCK per lock per backend, LockCountMyLocks() is no longer needed,
thus eliminating some O(N^2) behavior when a backend holds many locks.
Also simplify the LockAcquire/LockRelease API by passing just a
'sessionLock' boolean instead of a transaction ID.  The previous API
was designed with the idea that per-transaction lock holding would be
important for subtransactions, but now that we have subtransactions we
know that this is unwanted.  While at it, add an 'isTempObject' parameter
to LockAcquire to indicate whether the lock is being taken on a temp
table.  This is not used just yet, but will be needed shortly for
two-phase commit.

are now reported via elog, eliminating the need to test the result code
at most call sites.  Make it possible for the caller to distinguish a
freshly acquired lock from one already held in the current transaction.
Use that capability to avoid redundant AcceptInvalidationMessages() calls
in LockRelation().

spotted by Qingqing Zhou.  The HASH_ENTER action now automatically
fails with elog(ERROR) on out-of-memory --- which incidentally lets
us eliminate duplicate error checks in quite a bunch of places.  If
you really need the old return-NULL-on-out-of-memory behavior, you
can ask for HASH_ENTER_NULL.  But there is now an Assert in that path
checking that you aren't hoping to get that behavior in a palloc-based
hash table.
Along the way, remove the old HASH_FIND_SAVE/HASH_REMOVE_SAVED actions,
which were not being used anywhere anymore, and were surely too ugly
and unsafe to want to see revived again.

Also, remove the rather useless return value of LockReleaseAll.  Change
response to detection of corruption in the shared lock tables to PANIC,
since that is the only way of cleaning up fully.
Originally an idea of Heikki Linnakangas, variously hacked on 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.

memset() or MemSet() to a char *. For one, memset()'s first argument is
a void *, and further void * can be implicitly coerced to/from any other
pointer type.

is contention for a tuple-level lock.  This solves the problem of a
would-be exclusive locker being starved out by an indefinite succession
of share-lockers.  Per recent discussion with Alvaro.

Essentially, we shoehorn in a lockable-object-type field by taking
a byte away from the lockmethodid, which can surely fit in one byte
instead of two.  This allows less artificial definitions of all the
other fields of LOCKTAG; we can get rid of the special pg_xactlock
pseudo-relation, and also support locks on individual tuples and
general database objects (including shared objects).  None of those
possibilities are actually exploited just yet, however.

I removed pg_xactlock from pg_class, but did not force initdb for
that change.  At this point, relkind 's' (SPECIAL) is unused and
could be removed entirely.

to eliminate unnecessary deadlocks.  This commit adds SELECT ... FOR SHARE
paralleling SELECT ... FOR UPDATE.  The implementation uses a new SLRU
data structure (managed much like pg_subtrans) to represent multiple-
transaction-ID sets.  When more than one transaction is holding a shared
lock on a particular row, we create a MultiXactId representing that set
of transactions and store its ID in the row's XMAX.  This scheme allows
an effectively unlimited number of row locks, just as we did before,
while not costing any extra overhead except when a shared lock actually
has to be shared.   Still TODO: use the regular lock manager to control
the grant order when multiple backends are waiting for a row lock.

Alvaro Herrera and Tom Lane.

avoid encroaching on the 'user' range of OIDs by allowing automatic
OID assignment to use values below 16k until we reach normal operation.

initdb not forced since this doesn't make any incompatible change;
however a lot of stuff will have different OIDs after your next initdb.

it must occur *before* we get into the critical state of holding a
lock we have no place to record.  Per discussion with Qingqing Zhou.

the held_lwlocks[] array.  Per Qingqing Zhou.

no held locks.  This maintains the invariant that proclocks are present
only for procs that are holding or awaiting a lock; when this is not
true, LockRelease will fail.  Per report from Stephen Clouse.

macros around strings that were missing them.

from LockRelease() and LockReleaseAll() into it. From Heikki Linnakangas.

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 ...

R?mi Zara

no need for it to be nearly as big as the global hash table, and since
it's not in shared memory it can grow if it does need to be bigger.
By reducing the size, we speed up hash_seq_search(), which saves a
significant fraction of subtransaction entry/exit overhead.

returning a NULL pointer (some callers remembered to check the return
value, but some did not -- it is safer to just bail out).

Also, cleanup pgstat.c to use elog(ERROR) rather than elog(LOG) followed
by exit().