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Fix recently-understood problems with handling of XID freezing, particularly

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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have been replaced by FrozenTransactionId.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.
This commit is contained in:
Tom Lane
2006-11-05 22:42:10 +00:00
parent 10c70b8602
commit 48188e1621
43 changed files with 1284 additions and 1062 deletions
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30
src/backend/postmaster/postmaster.c
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@ -37,7 +37,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/postmaster/postmaster.c,v 1.500 2006/10/04 00:29:56 momjian Exp $
* $PostgreSQL: pgsql/src/backend/postmaster/postmaster.c,v 1.501 2006/11/05 22:42:09 tgl Exp $
*
* NOTES
*
@ -217,6 +217,8 @@ static bool FatalError = false; /* T if recovering from backend crash */
bool ClientAuthInProgress = false; /* T during new-client
* authentication */
static bool force_autovac = false; /* received START_AUTOVAC signal */
/*
* State for assigning random salts and cancel keys.
* Also, the global MyCancelKey passes the cancel key assigned to a given
@ -1231,9 +1233,13 @@ ServerLoop(void)
* (It'll die relatively quickly.) We check that it's not started too
* frequently in autovac_start.
*/
if (AutoVacuumingActive() && AutoVacPID == 0 &&
if ((AutoVacuumingActive() || force_autovac) && AutoVacPID == 0 &&
StartupPID == 0 && !FatalError && Shutdown == NoShutdown)
{
AutoVacPID = autovac_start();
if (AutoVacPID != 0)
force_autovac = false; /* signal successfully processed */
}
/* If we have lost the archiver, try to start a new one */
if (XLogArchivingActive() && PgArchPID == 0 &&
@ -2100,9 +2106,7 @@ reaper(SIGNAL_ARGS)
/*
* Was it the autovacuum process? Normal exit can be ignored; we'll
* start a new one at the next iteration of the postmaster's main
* loop, if necessary.
*
* An unexpected exit must crash the system.
* loop, if necessary. An unexpected exit is treated as a crash.
*/
if (AutoVacPID != 0 && pid == AutoVacPID)
{
@ -3424,12 +3428,16 @@ sigusr1_handler(SIGNAL_ARGS)
if (CheckPostmasterSignal(PMSIGNAL_START_AUTOVAC))
{
/* start one iteration of the autovacuum daemon */
if (Shutdown == NoShutdown)
{
Assert(!AutoVacuumingActive());
AutoVacPID = autovac_start();
}
/*
* Start one iteration of the autovacuum daemon, even if autovacuuming
* is nominally not enabled. This is so we can have an active defense
* against transaction ID wraparound. We set a flag for the main loop
* to do it rather than trying to do it here --- this is because the
* autovac process itself may send the signal, and we want to handle
* that by launching another iteration as soon as the current one
* completes.
*/
force_autovac = true;
}
PG_SETMASK(&UnBlockSig);