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Small performance improvement --- use indexscan not heapscan to find 

pg_statistic rows to delete while dropping a relation.
This commit is contained in:
Tom Lane 2002-07-19 22:21:17 +00:00
parent 59a471fc4c
commit 009d593c48
1 changed files with 13 additions and 8 deletions
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21
src/backend/catalog/heap.c
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@ -8,7 +8,7 @@
* *
* *
* IDENTIFICATION * IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/catalog/heap.c,v 1.210 2002/07/18 16:47:22 tgl Exp $ * $Header: /cvsroot/pgsql/src/backend/catalog/heap.c,v 1.211 2002/07/19 22:21:17 tgl Exp $
* *
* *
* INTERFACE ROUTINES * INTERFACE ROUTINES
@ -793,7 +793,8 @@ heap_create_with_catalog(const char *relname,
* Formerly, this routine checked for child relations and aborted the * Formerly, this routine checked for child relations and aborted the
* deletion if any were found. Now we rely on the dependency mechanism * deletion if any were found. Now we rely on the dependency mechanism
* to check for or delete child relations. By the time we get here, * to check for or delete child relations. By the time we get here,
* there are no children and we need only remove the pg_inherits rows. * there are no children and we need only remove any pg_inherits rows
* linking this relation to its parent(s).
*/ */
static void static void
RelationRemoveInheritance(Relation relation) RelationRemoveInheritance(Relation relation)
@ -1743,21 +1744,25 @@ static void
RemoveStatistics(Relation rel) RemoveStatistics(Relation rel)
{ {
Relation pgstatistic; Relation pgstatistic;
HeapScanDesc scan; SysScanDesc scan;
ScanKeyData key; ScanKeyData key;
HeapTuple tuple; HeapTuple tuple;
pgstatistic = heap_openr(StatisticRelationName, RowExclusiveLock); pgstatistic = heap_openr(StatisticRelationName, RowExclusiveLock);
ScanKeyEntryInitialize(&key, 0x0, Anum_pg_statistic_starelid, ScanKeyEntryInitialize(&key, 0x0,
F_OIDEQ, Anum_pg_statistic_starelid, F_OIDEQ,
ObjectIdGetDatum(RelationGetRelid(rel))); ObjectIdGetDatum(RelationGetRelid(rel)));
scan = heap_beginscan(pgstatistic, SnapshotNow, 1, &key);
while ((tuple = heap_getnext(scan, ForwardScanDirection)) != NULL) scan = systable_beginscan(pgstatistic, StatisticRelidAttnumIndex, true,
SnapshotNow, 1, &key);
while (HeapTupleIsValid(tuple = systable_getnext(scan)))
{
simple_heap_delete(pgstatistic, &tuple->t_self); simple_heap_delete(pgstatistic, &tuple->t_self);
}
heap_endscan(scan); systable_endscan(scan);
heap_close(pgstatistic, RowExclusiveLock); heap_close(pgstatistic, RowExclusiveLock);
} }