Since I wanted to know it, I extended explain to output the used (only the
first)
index on IndexScan.
An explain with this patch applied says:
template1=> explain select * from pg_class where oid=1;
NOTICE: QUERY PLAN:
Index Scan using pg_class_oid_index on pg_class (cost=2.03 size=1 width=74)
EXPLAIN
Does somebody want to add it to CVS please ?
Andreas
--- src/backend/commands/explain.c Tue Mar 3 21:10:34 1998
+++
src/backend/commands/explain.c.orig Thu Feb 26 05:30:58 1998
@@ -23,6
+23,7 @@
#include <parser/parse_node.h>
#include <optimizer/planner.h>
#include <access/xact.h>
+#include <utils/relcache.h>
typedef struct
ExplainState
{
@@ -117,6 +118,8 @@
static void
explain_outNode(StringInfo
str, Plan *plan, int indent, ExplainState *es)
{
+ List
*l;
+ Relation relation;
char *pname;
char
buf[1000];
int i;
@@ -184,8 +187,12 @@
appendStringInfo(str, pname);
switch (nodeTag(plan))
{
-
case T_SeqScan:
case T_IndexScan:
+
appendStringInfo(str, " using ");
+ l = ((IndexScan *)
plan)->indxid;
+ relation =
RelationIdCacheGetRelation((int) lfirst(l));
+
appendStringInfo(str, (RelationGetRelationName(relation))->data);
+
case T_SeqScan:
if (((Scan *) plan)->scanrelid > 0)
{
RangeTblEntry *rte = nth(((Scan *)
plan)->scanrelid - 1, es->rtable);