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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have been replaced by FrozenTransactionId.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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36
src/backend/utils/init/flatfiles.c
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@ -23,7 +23,7 @@
* Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $PostgreSQL: pgsql/src/backend/utils/init/flatfiles.c,v 1.21 2006/07/14 14:52:25 momjian Exp $
* $PostgreSQL: pgsql/src/backend/utils/init/flatfiles.c,v 1.22 2006/11/05 22:42:09 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -163,7 +163,7 @@ name_okay(const char *str)
/*
* write_database_file: update the flat database file
*
* A side effect is to determine the oldest database's datminxid
* A side effect is to determine the oldest database's datfrozenxid
* so we can set or update the XID wrap limit.
*/
static void
@ -177,7 +177,7 @@ write_database_file(Relation drel)
HeapScanDesc scan;
HeapTuple tuple;
NameData oldest_datname;
TransactionId oldest_datminxid = InvalidTransactionId;
TransactionId oldest_datfrozenxid = InvalidTransactionId;
/*
* Create a temporary filename to be renamed later. This prevents the
@ -208,27 +208,23 @@ write_database_file(Relation drel)
char *datname;
Oid datoid;
Oid dattablespace;
TransactionId datminxid,
datvacuumxid;
TransactionId datfrozenxid;
datname = NameStr(dbform->datname);
datoid = HeapTupleGetOid(tuple);
dattablespace = dbform->dattablespace;
datminxid = dbform->datminxid;
datvacuumxid = dbform->datvacuumxid;
datfrozenxid = dbform->datfrozenxid;
/*
* Identify the oldest datminxid, ignoring databases that are not
* connectable (we assume they are safely frozen). This must match
* Identify the oldest datfrozenxid. This must match
* the logic in vac_truncate_clog() in vacuum.c.
*/
if (dbform->datallowconn &&
TransactionIdIsNormal(datminxid))
if (TransactionIdIsNormal(datfrozenxid))
{
if (oldest_datminxid == InvalidTransactionId ||
TransactionIdPrecedes(datminxid, oldest_datminxid))
if (oldest_datfrozenxid == InvalidTransactionId ||
TransactionIdPrecedes(datfrozenxid, oldest_datfrozenxid))
{
oldest_datminxid = datminxid;
oldest_datfrozenxid = datfrozenxid;
namestrcpy(&oldest_datname, datname);
}
}
@ -244,14 +240,14 @@ write_database_file(Relation drel)
}
/*
* The file format is: "dbname" oid tablespace minxid vacuumxid
* The file format is: "dbname" oid tablespace frozenxid
*
* The xids are not needed for backend startup, but are of use to
* autovacuum, and might also be helpful for forensic purposes.
*/
fputs_quote(datname, fp);
fprintf(fp, " %u %u %u %u\n",
datoid, dattablespace, datminxid, datvacuumxid);
fprintf(fp, " %u %u %u\n",
datoid, dattablespace, datfrozenxid);
}
heap_endscan(scan);
@ -272,10 +268,10 @@ write_database_file(Relation drel)
tempname, filename)));
/*
* Set the transaction ID wrap limit using the oldest datminxid
* Set the transaction ID wrap limit using the oldest datfrozenxid
*/
if (oldest_datminxid != InvalidTransactionId)
SetTransactionIdLimit(oldest_datminxid, &oldest_datname);
if (oldest_datfrozenxid != InvalidTransactionId)
SetTransactionIdLimit(oldest_datfrozenxid, &oldest_datname);
}