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

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have been replaced by FrozenTransactionId.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

View File

@@ -7,7 +7,7 @@
* Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $PostgreSQL: pgsql/src/include/access/transam.h,v 1.58 2006/07/10 16:20:51 alvherre Exp $
* $PostgreSQL: pgsql/src/include/access/transam.h,v 1.59 2006/11/05 22:42:10 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -23,7 +23,7 @@
* always be considered valid.
*
* FirstNormalTransactionId is the first "normal" transaction id.
* Note: if you need to change it, you must change it in pg_class.h as well.
* Note: if you need to change it, you must change pg_class.h as well.
* ----------------
*/
#define InvalidTransactionId ((TransactionId) 0)
@@ -88,6 +88,9 @@ typedef struct VariableCacheData
Oid nextOid; /* next OID to assign */
uint32 oidCount; /* OIDs available before must do XLOG work */
TransactionId nextXid; /* next XID to assign */
TransactionId oldestXid; /* cluster-wide minimum datfrozenxid */
TransactionId xidVacLimit; /* start forcing autovacuums here */
TransactionId xidWarnLimit; /* start complaining here */
TransactionId xidStopLimit; /* refuse to advance nextXid beyond here */
TransactionId xidWrapLimit; /* where the world ends */
@@ -124,7 +127,7 @@ extern bool TransactionIdFollowsOrEquals(TransactionId id1, TransactionId id2);
/* in transam/varsup.c */
extern TransactionId GetNewTransactionId(bool isSubXact);
extern TransactionId ReadNewTransactionId(void);
extern void SetTransactionIdLimit(TransactionId oldest_datminxid,
extern void SetTransactionIdLimit(TransactionId oldest_datfrozenxid,
Name oldest_datname);
extern Oid GetNewObjectId(void);