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| author | Tom Lane <tgl@sss.pgh.pa.us> | 2011-10-11 14:20:06 -0400 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2011-10-11 14:21:30 -0400 |
| commit | a0185461dd94c8d31d8d55a7f2839b0d2f172ab9 (patch) | |
| tree | 3bd68d4e123336bbdefa8fd92372f0af7fb6d64f /src/backend/executor/execAmi.c | |
| parent | fa351d5a0db0672b6f586315720302e493116f27 (diff) | |
| download | postgresql-a0185461dd94c8d31d8d55a7f2839b0d2f172ab9.tar.gz | |
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).
Diffstat (limited to 'src/backend/executor/execAmi.c')
| -rw-r--r-- | src/backend/executor/execAmi.c | 21 |
1 files changed, 20 insertions, 1 deletions
diff --git a/src/backend/executor/execAmi.c b/src/backend/executor/execAmi.c index 711e8c7786..fa27640fed 100644 --- a/src/backend/executor/execAmi.c +++ b/src/backend/executor/execAmi.c @@ -26,6 +26,7 @@ #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" @@ -155,6 +156,10 @@ ExecReScan(PlanState *node) ExecReScanIndexScan((IndexScanState *) node); break; + case T_IndexOnlyScanState: + ExecReScanIndexOnlyScan((IndexOnlyScanState *) node); + break; + case T_BitmapIndexScanState: ExecReScanBitmapIndexScan((BitmapIndexScanState *) node); break; @@ -273,6 +278,10 @@ ExecMarkPos(PlanState *node) ExecIndexMarkPos((IndexScanState *) node); break; + case T_IndexOnlyScanState: + ExecIndexOnlyMarkPos((IndexOnlyScanState *) node); + break; + case T_TidScanState: ExecTidMarkPos((TidScanState *) node); break; @@ -326,6 +335,10 @@ ExecRestrPos(PlanState *node) ExecIndexRestrPos((IndexScanState *) node); break; + case T_IndexOnlyScanState: + ExecIndexOnlyRestrPos((IndexOnlyScanState *) node); + break; + case T_TidScanState: ExecTidRestrPos((TidScanState *) node); break; @@ -371,6 +384,7 @@ ExecSupportsMarkRestore(NodeTag plantype) { case T_SeqScan: case T_IndexScan: + case T_IndexOnlyScan: case T_TidScan: case T_ValuesScan: case T_Material: @@ -442,6 +456,10 @@ ExecSupportsBackwardScan(Plan *node) return IndexSupportsBackwardScan(((IndexScan *) node)->indexid) && TargetListSupportsBackwardScan(node->targetlist); + case T_IndexOnlyScan: + return IndexSupportsBackwardScan(((IndexOnlyScan *) node)->indexid) && + TargetListSupportsBackwardScan(node->targetlist); + case T_SubqueryScan: return ExecSupportsBackwardScan(((SubqueryScan *) node)->subplan) && TargetListSupportsBackwardScan(node->targetlist); @@ -474,7 +492,8 @@ TargetListSupportsBackwardScan(List *targetlist) } /* - * An IndexScan node supports backward scan only if the index's AM does. + * An IndexScan or IndexOnlyScan node supports backward scan only if the + * index's AM does. */ static bool IndexSupportsBackwardScan(Oid indexid) |