From a0185461dd94c8d31d8d55a7f2839b0d2f172ab9 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Tue, 11 Oct 2011 14:20:06 -0400 Subject: Rearrange the implementation of index-only scans. This commit changes index-only scans so that data is read directly from the index tuple without first generating a faux heap tuple. The only immediate benefit is that indexes on system columns (such as OID) can be used in index-only scans, but this is necessary infrastructure if we are ever to support index-only scans on expression indexes. The executor is now ready for that, though the planner still needs substantial work to recognize the possibility. To do this, Vars in index-only plan nodes have to refer to index columns not heap columns. I introduced a new special varno, INDEX_VAR, to mark such Vars to avoid confusion. (In passing, this commit renames the two existing special varnos to OUTER_VAR and INNER_VAR.) This allows ruleutils.c to handle them with logic similar to what we use for subplan reference Vars. Since index-only scans are now fundamentally different from regular indexscans so far as their expression subtrees are concerned, I also chose to change them to have their own plan node type (and hence, their own executor source file). --- src/backend/commands/trigger.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'src/backend/commands/trigger.c') diff --git a/src/backend/commands/trigger.c b/src/backend/commands/trigger.c index 06d368e0773..9fb97548485 100644 --- a/src/backend/commands/trigger.c +++ b/src/backend/commands/trigger.c @@ -2734,9 +2734,9 @@ TriggerEnabled(EState *estate, ResultRelInfo *relinfo, oldContext = MemoryContextSwitchTo(estate->es_query_cxt); tgqual = stringToNode(trigger->tgqual); - /* Change references to OLD and NEW to INNER and OUTER */ - ChangeVarNodes(tgqual, PRS2_OLD_VARNO, INNER, 0); - ChangeVarNodes(tgqual, PRS2_NEW_VARNO, OUTER, 0); + /* Change references to OLD and NEW to INNER_VAR and OUTER_VAR */ + ChangeVarNodes(tgqual, PRS2_OLD_VARNO, INNER_VAR, 0); + ChangeVarNodes(tgqual, PRS2_NEW_VARNO, OUTER_VAR, 0); /* ExecQual wants implicit-AND form */ tgqual = (Node *) make_ands_implicit((Expr *) tgqual); *predicate = (List *) ExecPrepareExpr((Expr *) tgqual, estate); @@ -2783,7 +2783,7 @@ TriggerEnabled(EState *estate, ResultRelInfo *relinfo, /* * Finally evaluate the expression, making the old and/or new tuples - * available as INNER/OUTER respectively. + * available as INNER_VAR/OUTER_VAR respectively. */ econtext->ecxt_innertuple = oldslot; econtext->ecxt_outertuple = newslot; -- cgit v1.2.3