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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have been replaced by FrozenTransactionId.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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10
src/backend/utils/time/tqual.c
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@@ -32,7 +32,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/utils/time/tqual.c,v 1.98 2006/10/04 00:30:04 momjian Exp $
* $PostgreSQL: pgsql/src/backend/utils/time/tqual.c,v 1.99 2006/11/05 22:42:09 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -1099,9 +1099,11 @@ HeapTupleSatisfiesVacuum(HeapTupleHeader tuple, TransactionId OldestXmin,
{
/*
* "Deleting" xact really only locked it, so the tuple is live in any
* case. However, we must make sure that either XMAX_COMMITTED or
* XMAX_INVALID gets set once the xact is gone; otherwise it is unsafe
* to recycle CLOG status after vacuuming.
* case. However, we should make sure that either XMAX_COMMITTED or
* XMAX_INVALID gets set once the xact is gone, to reduce the costs
* of examining the tuple for future xacts. Also, marking dead
* MultiXacts as invalid here provides defense against MultiXactId
* wraparound (see also comments in heap_freeze_tuple()).
*/
if (!(tuple->t_infomask & HEAP_XMAX_COMMITTED))
{