CVS log for pgsql/src/include/storage/proc.h

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pgindent run for 9.0

Re-enable max_standby_delay = -1 using deadlock detection on startup
process. If startup waits on a buffer pin we send a request to all
backends to cancel themselves if they are holding the buffer pin
required and they are also waiting on a lock. If not, startup waits
until max_standby_delay before cancelling any backend waiting for
the requested buffer pin.

In HS, Startup process sets SIGALRM when waiting for buffer pin. If
woken by alarm we send SIGUSR1 to all backends requesting that they
check to see if they are blocking Startup process. If so, they throw
ERROR/FATAL as for other conflict resolutions. Deadlock stop gap
removed. max_standby_delay = -1 option removed to prevent deadlock.

Teach standby conflict resolution to use SIGUSR1
Conflict reason is passed through directly to the backend, so we can
take decisions about the effect of the conflict based upon the local
state. No specific changes, as yet, though this prepares for later work.
CancelVirtualTransaction() sends signals while holding ProcArrayLock.
Introduce errdetail_abort() to give message detail explaining that the
abort was caused by conflict processing. Remove CONFLICT_MODE states
in favour of using PROCSIG_RECOVERY_CONFLICT states directly, for clarity.

Introduce Streaming Replication.

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

Update copyright for the year 2010.

Allow read only connections during recovery, known as Hot Standby.

Enabled by recovery_connections = on (default) and forcing archive recovery using a recovery.conf. Recovery processing now emulates the original transactions as they are replayed, providing full locking and MVCC behaviour for read only queries. Recovery must enter consistent state before connections are allowed, so there is a delay, typically short, before connections succeed. Replay of recovering transactions can conflict and in some cases deadlock with queries during recovery; these result in query cancellation after max_standby_delay seconds have expired. Infrastructure changes have minor effects on normal running, though introduce four new types of WAL record.

New test mode "make standbycheck" allows regression tests of static command behaviour on a standby server while in recovery. Typical and extreme dynamic behaviours have been checked via code inspection and manual testing. Few port specific behaviours have been utilised, though primary testing has been on Linux only so far.

This commit is the basic patch. Additional changes will follow in this release to enhance some aspects of behaviour, notably improved handling of conflicts, deadlock detection and query cancellation. Changes to VACUUM FULL are also required.

Simon Riggs, with significant and lengthy review by Heikki Linnakangas, including streamlined redesign of snapshot creation and two-phase commit.

Important contributions from Florian Pflug, Mark Kirkwood, Merlin Moncure, Greg Stark, Gianni Ciolli, Gabriele Bartolini, Hannu Krosing, Robert Haas, Tatsuo Ishii, Hiroyuki Yamada plus support and feedback from many other community members.

Change the autovacuum launcher to read pg_database directly, rather than
via the "flat files" facility.  This requires making it enough like a backend
to be able to run transactions; it's no longer an "auxiliary process" but
more like the autovacuum worker processes.  Also, its signal handling has
to be brought into line with backends/workers.  In particular, since it
now has to handle procsignal.c processing, the special autovac-launcher-only
signal conditions are moved to SIGUSR2.

Alvaro, with some cleanup from Tom

Allow backends to start up without use of the flat-file copy of pg_database.

To make this work in the base case, pg_database now has a nailed-in-cache
relation descriptor that is initialized using hardwired knowledge in
relcache.c.  This means pg_database is added to the set of relations that
need to have a Schema_pg_xxx macro maintained in pg_attribute.h.  When this
path is taken, we'll have to do a seqscan of pg_database to find the row
we need.

In the normal case, we are able to do an indexscan to find the database's row
by name.  This is made possible by storing a global relcache init file that
describes only the shared catalogs and their indexes (and therefore is usable
by all backends in any database).  A new backend loads this cache file,
finds its database OID after an indexscan on pg_database, and then loads
the local relcache init file for that database.

This change should effectively eliminate number of databases as a factor
in backend startup time, even with large numbers of databases.  However,
the real reason for doing it is as a first step towards getting rid of
the flat files altogether.  There are still several other sub-projects
to be tackled before that can happen.

Change the signaling of end-of-recovery. Startup process now indicates end
of recovery by exiting with exit code 0, like in previous releases. Per
Tom's suggestion.

Increase NUM_AUXILIARY_PROCS, now that the startup process can co-exist
with other auxiliary processes for a short period. As witnessed by
buildfarm member dungbeetle.

Update copyright for 2009.

Revert SIGUSR1 multiplexing patch, per Tom's objection.

Provide support for multiplexing SIGUSR1 signal. The upcoming synchronous
replication patch needs a signal, but we've already used SIGUSR1 and
SIGUSR2 in normal backends. This patch allows reusing SIGUSR1 for that,
and for other purposes too if the need arises.

Remove the last vestiges of the MAKE_PTR/MAKE_OFFSET mechanism.  We haven't
allowed different processes to have different addresses for the shmem segment
in quite a long time, but there were still a few places left that used the
old coding convention.  Clean them up to reduce confusion and improve the
compiler's ability to detect pointer type mismatches.

Kris Jurka

Revert addition of pg_terminate_backend() because of race conditions.

Add pg_terminate_backend() to allow terminating only a single session.

Change StatementCancelHandler() to check the DoingCommandRead flag to decide
whether to execute an immediate interrupt, rather than testing whether
LockWaitCancel() cancelled a lock wait.  The old way misclassified the case
where we were blocked in ProcWaitForSignal(), and arguably would misclassify
any other future additions of new ImmediateInterruptOK states too.  This
allows reverting the old kluge that gave LockWaitCancel() a return value,
since no callers care anymore.  Improve comments in the various
implementations of PGSemaphoreLock() to explain that on some platforms, the
assumption that semop() exits after a signal is wrong, and so we must ensure
that the signal handler itself throws elog if we want cancel or die interrupts
to be effective.  Per testing related to bug #3883, though this patch doesn't
solve those problems fully.

Perhaps this change should be back-patched, but since pre-8.3 branches aren't
really relying on autovacuum to respond to SIGINT, it doesn't seem critical
for them.

Update copyrights in source tree to 2008.

pgindent run for 8.3.

Rearrange vacuum-related bits in PGPROC as a bitmask, to better support
having several of them.  Add two more flags: whether the process is
executing an ANALYZE, and whether a vacuum is for Xid wraparound (which
is obviously only set by autovacuum).

Sneakily move the worker's recently-acquired PostAuthDelay to a more useful
place.

Implement lazy XID allocation: transactions that do not modify any database
rows will normally never obtain an XID at all.  We already did things this way
for subtransactions, but this patch extends the concept to top-level
transactions.  In applications where there are lots of short read-only
transactions, this should improve performance noticeably; not so much from
removal of the actual XID-assignments, as from reduction of overhead that's
driven by the rate of XID consumption.  We add a concept of a "virtual
transaction ID" so that active transactions can be uniquely identified even
if they don't have a regular XID.  This is a much lighter-weight concept:
uniqueness of VXIDs is only guaranteed over the short term, and no on-disk
record is made about them.

Florian Pflug, with some editorialization by Tom.

Rename DLLIMPORT macro to PGDLLIMPORT to avoid conflict with
third party includes (like tcl) that define DLLIMPORT.

Add a multi-worker capability to autovacuum.  This allows multiple worker
processes to be running simultaneously.  Also, now autovacuum processes do not
count towards the max_connections limit; they are counted separately from
regular processes, and are limited by the new GUC variable
autovacuum_max_workers.

The launcher now has intelligence to launch workers on each database every
autovacuum_naptime seconds, limited only on the max amount of worker slots
available.

Also, the global worker I/O utilization is limited by the vacuum cost-based
delay feature.  Workers are "balanced" so that the total I/O consumption does
not exceed the established limit.  This part of the patch was contributed by
ITAGAKI Takahiro.

Per discussion.

Remove the CheckpointStartLock in favor of having backends show whether they
are in their commit critical sections via flags in the ProcArray.  Checkpoint
can watch the ProcArray to determine when it's safe to proceed.  This is
a considerably better solution to the original problem of race conditions
between checkpoint and transaction commit: it speeds up commit, since there's
one less lock to fool with, and it prevents the problem of checkpoint being
delayed indefinitely when there's a constant flow of commits.  Heikki, with
some kibitzing from Tom.

Cleanup the bootstrap code a little, and rename "dummy procs" in the code
comments and variables to "auxiliary proc", per Heikki's request.

Add GUC log_lock_waits to log long wait times.

Simon Riggs

Restructure autovacuum in two processes: a dummy process, which runs
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.

Arrange for autovacuum to be killed when another operation wants to be alone
accessing it, like DROP DATABASE.  This allows the regression tests to pass
with autovacuum enabled, which open the gates for finally enabling autovacuum
by default.

Update CVS HEAD for 2007 copyright.  Back branches are typically not
back-stamped for this.

pgindent run for 8.2.

Modify snapshot definition so that lazy vacuums are ignored by other
vacuums.  This allows a OLTP-like system with big tables to continue
regular vacuuming on small-but-frequently-updated tables while the
big tables are being vacuumed.

Original patch from Hannu Krossing, rewritten by Tom Lane and updated
by me.

Allow include files to compile own their own.

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.

Repair a low-probability race condition identified by Qingqing Zhou.
If a process abandons a wait in LockBufferForCleanup (in practice,
only happens if someone cancels a VACUUM) just before someone else
sends it a signal indicating the buffer is available, it was possible
for the wakeup to remain in the process' semaphore, causing misbehavior
next time the process waited for an lmgr lock.  Rather than try to
prevent the race condition directly, it seems best to make the lock
manager robust against leftover wakeups, by having it repeat waiting
on the semaphore if the lock has not actually been granted or denied
yet.

Update copyright for 2006.  Update scripts.

Rearrange backend startup sequence so that ShmemIndexLock can become
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.

Divide the lock manager's shared state into 'partitions', so as to
reduce contention for the former single LockMgrLock.  Per my recent
proposal.  I set it up for 16 partitions, but on a pgbench test this
gives only a marginal further improvement over 4 partitions --- we need
to test more scenarios to choose the number of partitions.

Standard pgindent run for 8.1.

Add infrastructure for making spins_per_delay variable depending on
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.

Print proper cause of statement cancel, user interaction or timeout.

Convert the arithmetic for shared memory size calculation from 'int'
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.

Add per-user and per-database connection limit options.
This patch also includes preliminary update of pg_dumpall for roles.
Petr Jelinek, with review by Bruce Momjian and Tom Lane.

Two-phase commit.  Original patch by Heikki Linnakangas, with additional
hacking by Alvaro Herrera and Tom Lane.

Split the shared-memory array of PGPROC pointers out of the sinval
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.

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 ...

Minor adjustments to improve the accuracy of our computation of required
shared memory size.

Pgindent run for 8.0.

Update copyright to 2004.

Introduce local hash table for lock state, as per recent proposal.
PROCLOCK structs in shared memory now have only a bitmask for held
locks, rather than counts (making them 40 bytes smaller, which is a
good thing).  Multiple locks within a transaction are counted in the
local hash table instead, and we have provision for tracking which
ResourceOwner each count belongs to.  Solves recently reported problem
with memory leakage within long transactions.

Some mop-up work for savepoints (nested transactions).  Store a small
number of active subtransaction XIDs in each backend's PGPROC entry,
and use this to avoid expensive probes into pg_subtrans during
TransactionIdIsInProgress.  Extend EOXactCallback API to allow add-on
modules to get control at subxact start/end.  (This is deliberately
not compatible with the former API, since any uses of that API probably
need manual review anyway.)  Add basic reference documentation for
SAVEPOINT and related commands.  Minor other cleanups to check off some
of the open issues for subtransactions.
Alvaro Herrera and Tom Lane.

Back out pg_autovacuum commit after cvs clean failure causes commit.

lease find enclosed a patch that matches the PL/Perl documentation
(fairly closely, I hope) to the current PL/Perl implementation.

David Fetter

Invent ResourceOwner mechanism as per my recent proposal, and use it to
keep track of portal-related resources separately from transaction-related
resources.  This allows cursors to work in a somewhat sane fashion with
nested transactions.  For now, cursor behavior is non-subtransactional,
that is a cursor's state does not roll back if you abort a subtransaction
that fetched from the cursor.  We might want to change that later.

Nested transactions.  There is still much left to do, especially on the
performance front, but with feature freeze upon us I think it's time to
drive a stake in the ground and say that this will be in 7.5.

Alvaro Herrera, with some help from Tom Lane.

Try to reduce confusion about what is a lock method identifier, a lock
method control structure, or a table of control structures.

. Use type LOCKMASK where an int is not a counter.

. Get rid of INVALID_TABLEID, use INVALID_LOCKMETHOD instead.

. Use INVALID_LOCKMETHOD instead of (LOCKMETHOD) NULL, because
  LOCKMETHOD is not a pointer.

. Define and use macro LockMethodIsValid.

. Rename LOCKMETHOD to LOCKMETHODID.

. Remove global variable LongTermTableId in lmgr.c, because it is
  never used.

. Make LockTableId static in lmgr.c, because it is used nowhere else.
  Why not remove it and use DEFAULT_LOCKMETHOD?

. Rename the lock method control structure from LOCKMETHODTABLE to
  LockMethodData.  Introduce a pointer type named LockMethod.

. Remove elog(FATAL) after InitLockTable() call in
  CreateSharedMemoryAndSemaphores(), because if something goes wrong,
  there is elog(FATAL) in LockMethodTableInit(), and if this doesn't
  help, an elog(ERROR) in InitLockTable() is promoted to FATAL.

. Make InitLockTable() void, because its only caller does not use its
  return value any more.

. Rename variables in lock.c to avoid statements like
        LockMethodTable[NumLockMethods] = lockMethodTable;
        lockMethodTable = LockMethodTable[lockmethod];

. Change LOCKMETHODID type to uint16 to fit into struct LOCKTAG.

. Remove static variables BITS_OFF and BITS_ON from lock.c, because
  I agree to this doubt:
 * XXX is a fetch from a static array really faster than a shift?

. Define and use macros LOCKBIT_ON/OFF.


Manfred Koizar

make sure the $Id tags are converted to $PostgreSQL as well ...

Background writer process

This first part of the background writer does no syncing at all.
It's only purpose is to keep the LRU heads clean so that regular
backends seldom to never have to call write().

Jan

Update copyrights to 2003.

Rename 'holder' references to 'proclock' for PROCLOCK references, for
consistency.

Code review for statement_timeout patch.  Fix some race conditions
between signal handler and enable/disable code, avoid accumulation of
timing error due to trying to maintain remaining-time instead of
absolute-end-time, disable timeout before commit not after.

Add DLLIMPORT declarations needed by contrib modules.

pgindent run.

Complete TODO item:

* -HOLDER/HOLDERTAB rename to PROCLOCK/PROCLOCKTAG

Add SET statement_timeout capability.  Timeout is in ms.  A value of
zero turns off the timer.

Update copyright to 2002.

Katherine Ward wrote:
> Changes to avoid collisions with WIN32 & MFC names...
> 1.  Renamed:
>       a.  PROC => PGPROC
>       b.  GetUserName() => GetUserNameFromId()
>       c.  GetCurrentTime() => GetCurrentDateTime()
>       d.  IGNORE => IGNORE_DTF in include/utils/datetime.h & utils/adt/datetim
>
> 2.  Added _P to some lex/yacc tokens:
>       CONST, CHAR, DELETE, FLOAT, GROUP, IN, OUT

Jan

Create an internal semaphore API that is not tied to SysV semaphores.
As proof of concept, provide an alternate implementation based on POSIX
semaphores.  Also push the SysV shared-memory implementation into a
separate file so that it can be replaced conveniently.

The extra semaphore that proc.c now allocates for checkpoint processes
should be accounted for in the PROC_SEM_MAP_ENTRIES() macro.  Otherwise
the ports that rely on this macro to size data structures are broken.
Mea culpa.

New pgindent run with fixes suggested by Tom.  Patch manually reviewed,
initdb/regression tests pass.

Another pgindent run.  Fixes enum indenting, and improves #endif
spacing.  Also adds space for one-line comments.

pgindent run on all C files.  Java run to follow.  initdb/regression
tests pass.

Back out change.  Too many place to change too close to beta:

* HOLDER/HOLDERTAB rename to PROCLOCKLINK/PROCLOCKLINKTAG (Bruce)

Will return later.

Do this TODO item:

	* HOLDER/HOLDERTAB rename to PROCLOCK/PROCLOCKTAG (Tom)

Didn't use PROCLOCKLINK because it made PROCLOCKLINKTAG too long.

Implement new 'lightweight lock manager' that's intermediate between
existing lock manager and spinlocks: it understands exclusive vs shared
lock but has few other fancy features.  Replace most uses of spinlocks
with lightweight locks.  All remaining uses of spinlocks have very short
lock hold times (a few dozen instructions), so tweak spinlock backoff
code to work efficiently given this assumption.  All per my proposal on
pghackers 26-Sep-01.

Add an overall timeout on the client authentication cycle, so that
a hung client or lost connection can't indefinitely block a postmaster
child (not to mention the possibility of deliberate DoS attacks).
Timeout is controlled by new authentication_timeout GUC variable,
which I set to 60 seconds by default ... does that seem reasonable?

Get rid of PID entries in shmem hash table; there is no longer any need
for them, and making them just wastes time during backend startup/shutdown.
Also, remove compile-time MAXBACKENDS limit per long-ago proposal.
You can now set MaxBackends as high as your kernel can stand without
any reconfiguration/recompilation.

Implement LockBufferForCleanup(), which will allow concurrent VACUUM
to wait until it's safe to remove tuples and compact free space in a
shared buffer page.  Miscellaneous small code cleanups in bufmgr, too.

Tweak startup sequence so that running out of PROC array slots is
detected sooner in backend startup, and is treated as an expected error
(it gives 'Sorry, too many clients already' now).  This allows us not
to have to enforce the MaxBackends limit exactly in the postmaster.
Also, remove ProcRemove() and fold its functionality into ProcKill().
There's no good reason for a backend not to be responsible for removing
its PROC entry, and there are lots of good reasons for the postmaster
not to be touching shared-memory data structures.

Oops, only wanted python change in the last commit.  Backing out.

While changing Cygwin Python to build its core as a DLL (like Win32
Python) to support shared extension modules, I have learned that Guido
prefers the style of the attached patch to solve the above problem.
I feel that this solution is particularly appropriate in this case
because the following:

    PglargeType
    PgType
    PgQueryType

are already being handled in the way that I am proposing for PgSourceType.

Jason Tishler

pgindent run.  Make it all clean.

Implement COMMIT_SIBLINGS parameter to allow pre-commit delay to occur
only if at least N other backends currently have open transactions.  This
is not a great deal of intelligence about whether a delay might be
profitable ... but it beats no intelligence at all.  Note that the default
COMMIT_DELAY is still zero --- this new code does nothing unless that
setting is changed.
Also, mark ENABLEFSYNC as a system-wide setting.  It's no longer safe to
allow that to be set per-backend, since we may be relying on some other
backend's fsync to have synced the WAL log.

Re-implement deadlock detection and resolution, per design notes posted
to pghackers on 18-Jan-01.

Change Copyright from PostgreSQL, Inc to PostgreSQL Global Development Group.

Clean up lockmanager data structures some more, in preparation for planned
rewrite of deadlock checking.  Lock holder objects are now reachable from
the associated LOCK as well as from the owning PROC.  This makes it
practical to find all the processes holding a lock, as well as all those
waiting on the lock.  Also, clean up some of the grottier aspects of the
SHMQueue API, and cause the waitProcs list to be stored in the intuitive
direction instead of the nonintuitive one.  (Bet you didn't know that
the code followed the 'prev' link to get to the next waiting process,
instead of the 'next' link.  It doesn't do that anymore.)

Oops, I had managed to break query-cancel-while-waiting-for-lock.

Rename fields of lock and lockholder structures to something a tad less
confusing, and clean up documentation.

Restructure backend SIGINT/SIGTERM handling so that 'die' interrupts
are treated more like 'cancel' interrupts: the signal handler sets a
flag that is examined at well-defined spots, rather than trying to cope
with an interrupt that might happen anywhere.  See pghackers discussion
of 1/12/01.

Revise lock manager to support "session level" locks as well as "transaction
level" locks.  A session lock is not released at transaction commit (but it
is released on transaction abort, to ensure recovery after an elog(ERROR)).
In VACUUM, use a session lock to protect the master table while vacuuming a
TOAST table, so that the TOAST table can be done in an independent
transaction.

I also took this opportunity to do some cleanup and renaming in the lock
code.  The previously noted bug in ProcLockWakeup, that it couldn't wake up
any waiters beyond the first non-wakeable waiter, is now fixed.  Also found
a previously unknown bug of the same kind (failure to scan all members of
a lock queue in some cases) in DeadLockCheck.  This might have led to failure
to detect a deadlock condition, resulting in indefinite waits, but it's
difficult to characterize the conditions required to trigger a failure.

Significant cleanups in SysV IPC handling (shared mem and semaphores).
IPC key assignment will now work correctly even when multiple postmasters
are using same logical port number (which is possible given -k switch).
There is only one shared-mem segment per postmaster now, not 3.
Rip out broken code for non-TAS case in bufmgr and xlog, substitute a
complete S_LOCK emulation using semaphores in spin.c.  TAS and non-TAS
logic is now exactly the same.
When deadlock is detected, "Deadlock detected" is now the elog(ERROR)
message, rather than a NOTICE that comes out before an unhelpful ERROR.

The heralded `Grand Unified Configuration scheme' (GUC)

That means you can now set your options in either or all of $PGDATA/configuration,
some postmaster option (--enable-fsync=off), or set a SET command. The list of
options is in backend/utils/misc/guc.c, documentation will be written post haste.

pg_options is gone, so is that pq_geqo config file. Also removed were backend -K,
-Q, and -T options (no longer applicable, although -d0 does the same as -Q).

Added to configure an --enable-syslog option.

changed all callers from TPRINTF to elog(DEBUG)

Ye-old pgindent run.  Same 4-space tabs.

Change cancel while waiting-for-lock stuff.

Add:

  * Portions Copyright (c) 1996-2000, PostgreSQL, Inc

to all files copyright Regents of Berkeley.  Man, that's a lot of files.

Transaction log manager core code.
It doesn't work currently but also don't break anything -:)

Several changes here, not very related but touching some of the same files.
* Buffer refcount cleanup (per my "progress report" to pghackers, 9/22).
* Add links to backend PROC structs to sinval's array of per-backend info,
and use these links for routines that need to check the state of all
backends (rather than the slow, complicated search of the ShmemIndex
hashtable that was used before).  Add databaseOID to PROC structs.
* Use this to implement an interlock that prevents DESTROY DATABASE of
a database containing running backends.  (It's a little tricky to prevent
a concurrently-starting backend from getting in there, since the new
backend is not able to lock anything at the time it tries to look up
its database in pg_database.  My solution is to recheck that the DB is
OK at the end of InitPostgres.  It may not be a 100% solution, but it's
a lot better than no interlock at all...)
* In ALTER TABLE RENAME, flush buffers for the relation before doing the
rename of the physical files, to ensure we don't get failures later from
mdblindwrt().
* Update TRUNCATE patch so that it actually compiles against current
sources :-(.
You should do "make clean all" after pulling these changes.

Carefully merge in Bruce's include file changes ... commit'd only after a
clean compile ...

Change #include's to use <> and "" as appropriate.

Another pgindent run.  Sorry folks.

pgindent run over code.

Hi, Bruce!

These are my last changes to lmgr fixing deadlock handling.
Please apply them to cvs...

Vadim

Fix LMGR for MVCC.
Get rid of Extend lock mode.

Reorder startup ops so that if preallocation of semas fails,
postmaster will release whatever it did get before dying.

Allow maximum number of backends to be set at configure time
(--with-maxbackends).  Add a postmaster switch (-N backends) that allows
the limit to be reduced at postmaster start time.  (You can't increase it,
sorry to say, because there are still some fixed-size arrays.)
Grab the number of semaphores indicated by min(MAXBACKENDS, -N) at
postmaster startup, so that this particular form of bogus configuration
is exposed immediately rather than under heavy load.

Remove duplicate geqo functions, and more optimizer cleanup

Change my-function-name-- to my_function_name, and optimizer renames.

Initial MVCC code.
New code for locking buffer' context.

OK, folks, here is the pgindent output.

From: Massimo Dal Zotto <dz@cs.unitn.it>

lock.patch

        I have rewritten lock.c cleaning up the code and adding better
        assert checking I have also added some fields to the lock and
        xid tags for better support of user locks. There is also a new
        function which returns an array of pids owning a lock.
        I'm using this code from over six months and it works fine.

Use Snapshot in heap access methods.

Rename locking structure names to be clearer.  Add narrative to
backend flowchart.

pgindent run before 6.3 release, with Thomas' requested changes.

getpid/pid cleanup

Cleanup deadlock message.

Used modified version of indent that understands over 100 typedefs.

Another PGINDENT run that changes variable indenting and case label indenting.  Also static variable indenting.

Massive commit to run PGINDENT on all *.c and *.h files.

Make functions static where possible, enclose unused functions in #ifdef NOT_USED.

Remove WIN32 defines.  They never worked.

Another directory totally cleaned out

Added needed include file.

More cleanups of the include files

	- centralizing to simplify the -I's required to compile