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/executor/execProcnode.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) (limited to 'src/backend/executor/execProcnode.c') diff --git a/src/backend/executor/execProcnode.c b/src/backend/executor/execProcnode.c index 284fc6a63b7..8ab9892c850 100644 --- a/src/backend/executor/execProcnode.c +++ b/src/backend/executor/execProcnode.c @@ -89,6 +89,7 @@ #include "executor/nodeGroup.h" #include "executor/nodeHash.h" #include "executor/nodeHashjoin.h" +#include "executor/nodeIndexonlyscan.h" #include "executor/nodeIndexscan.h" #include "executor/nodeLimit.h" #include "executor/nodeLockRows.h" @@ -192,6 +193,11 @@ ExecInitNode(Plan *node, EState *estate, int eflags) estate, eflags); break; + case T_IndexOnlyScan: + result = (PlanState *) ExecInitIndexOnlyScan((IndexOnlyScan *) node, + estate, eflags); + break; + case T_BitmapIndexScan: result = (PlanState *) ExecInitBitmapIndexScan((BitmapIndexScan *) node, estate, eflags); @@ -397,6 +403,10 @@ ExecProcNode(PlanState *node) result = ExecIndexScan((IndexScanState *) node); break; + case T_IndexOnlyScanState: + result = ExecIndexOnlyScan((IndexOnlyScanState *) node); + break; + /* BitmapIndexScanState does not yield tuples */ case T_BitmapHeapScanState: @@ -627,6 +637,10 @@ ExecEndNode(PlanState *node) ExecEndIndexScan((IndexScanState *) node); break; + case T_IndexOnlyScanState: + ExecEndIndexOnlyScan((IndexOnlyScanState *) node); + break; + case T_BitmapIndexScanState: ExecEndBitmapIndexScan((BitmapIndexScanState *) node); break; -- cgit v1.2.3