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Fix autovacuum to avoid leaving non-permanent Xids in non-connectable

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databases.

Apply to the 8.1 branch only, as the new 8.2 (and HEAD) coding does not have
this problem.
This commit is contained in:
Alvaro Herrera 2007-01-14 20:18:30 +00:00
parent 0069d7c36a
commit d8b5a71c51
1 changed files with 55 additions and 28 deletions
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83
src/backend/postmaster/autovacuum.c
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@ -10,7 +10,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/postmaster/autovacuum.c,v 1.5.2.6 2006/05/19 15:15:38 alvherre Exp $
* $PostgreSQL: pgsql/src/backend/postmaster/autovacuum.c,v 1.5.2.7 2007/01/14 20:18:30 alvherre Exp $
*
*-------------------------------------------------------------------------
*/
@ -482,30 +482,19 @@ autovac_get_database_list(void)
}
/*
* Process a whole database. If it's a template database or is disallowing
* connection by means of datallowconn=false, then issue a VACUUM FREEZE.
* Else use a plain VACUUM.
* Return a palloc'ed copy of the pg_database entry for the given database.
* Note that no lock is retained on the entry whatsoever, so it may be stale by
* the time the caller inspects it. This is sufficient for our purposes
* however.
*/
static void
process_whole_db(void)
static Form_pg_database
get_pg_database_entry(Oid dbid)
{
Relation dbRel;
Form_pg_database dbForm;
ScanKeyData entry[1];
Relation dbRel;
SysScanDesc scan;
HeapTuple tup;
Form_pg_database dbForm;
bool freeze;
/* Start a transaction so our commands have one to play into. */
StartTransactionCommand();
/* functions in indexes may want a snapshot set */
ActiveSnapshot = CopySnapshot(GetTransactionSnapshot());
/*
* Clean up any dead statistics collector entries for this DB.
*/
pgstat_vacuum_tabstat();
dbRel = heap_open(DatabaseRelationId, AccessShareLock);
@ -523,17 +512,44 @@ process_whole_db(void)
if (!HeapTupleIsValid(tup))
elog(ERROR, "could not find tuple for database %u", MyDatabaseId);
dbForm = (Form_pg_database) GETSTRUCT(tup);
if (!dbForm->datallowconn || dbForm->datistemplate)
freeze = true;
else
freeze = false;
dbForm = (Form_pg_database) palloc(sizeof(FormData_pg_database));
memcpy(dbForm, GETSTRUCT(tup), sizeof(FormData_pg_database));
systable_endscan(scan);
heap_close(dbRel, AccessShareLock);
return dbForm;
}
/*
* Process a whole database. If it's a template database or is disallowing
* connection by means of datallowconn=false, then issue a VACUUM FREEZE.
* Else use a plain VACUUM.
*/
static void
process_whole_db(void)
{
Form_pg_database dbForm;
bool freeze;
/* Start a transaction so our commands have one to play into. */
StartTransactionCommand();
/* functions in indexes may want a snapshot set */
ActiveSnapshot = CopySnapshot(GetTransactionSnapshot());
/*
* Clean up any dead statistics collector entries for this DB.
*/
pgstat_vacuum_tabstat();
dbForm = get_pg_database_entry(MyDatabaseId);
freeze = (!dbForm->datallowconn || dbForm->datistemplate);
pfree(dbForm);
elog(DEBUG2, "autovacuum: VACUUM%s whole database",
(freeze) ? " FREEZE" : "");
@ -564,6 +580,8 @@ do_autovacuum(PgStat_StatDBEntry *dbentry)
List *toast_table_ids = NIL;
ListCell *cell;
PgStat_StatDBEntry *shared;
Form_pg_database dbForm;
bool istemplate;
/* Start a transaction so our commands have one to play into. */
StartTransactionCommand();
@ -578,6 +596,14 @@ do_autovacuum(PgStat_StatDBEntry *dbentry)
*/
pgstat_vacuum_tabstat();
/*
* In a template database, we need to avoid putting our Xid in any table,
* so disallow analyzes and force use of VACUUM FREEZE.
*/
dbForm = get_pg_database_entry(MyDatabaseId);
istemplate = (!dbForm->datallowconn || dbForm->datistemplate);
pfree(dbForm);
/*
* StartTransactionCommand and CommitTransactionCommand will automatically
* switch to other contexts. We need this one to keep the list of
@ -694,10 +720,11 @@ do_autovacuum(PgStat_StatDBEntry *dbentry)
VacuumCostDelay = tab->vacuum_cost_delay;
VacuumCostLimit = tab->vacuum_cost_limit;
/* in a template database, we never analyze and force freezing */
autovacuum_do_vac_analyze(list_make1_oid(tab->relid),
tab->dovacuum,
tab->doanalyze,
false);
!istemplate && tab->doanalyze,
istemplate);
}
/* Finally close out the last transaction. */