diff options
| author | Tom Lane <tgl@sss.pgh.pa.us> | 2011-10-07 20:13:02 -0400 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2011-10-07 20:14:13 -0400 |
| commit | a2822fb9337a21f98ac4ce850bb4145acf47ca27 (patch) | |
| tree | c239fe9a32ff0225e906711a76348cee1567f0d8 /src/backend/optimizer/plan/createplan.c | |
| parent | caa1054df8408b165e5f66ff25c87b6dd0a0a1e7 (diff) | |
| download | postgresql-a2822fb9337a21f98ac4ce850bb4145acf47ca27.tar.gz postgresql-a2822fb9337a21f98ac4ce850bb4145acf47ca27.zip | |
Support index-only scans using the visibility map to avoid heap fetches.
When a btree index contains all columns required by the query, and the
visibility map shows that all tuples on a target heap page are
visible-to-all, we don't need to fetch that heap page. This patch depends
on the previous patches that made the visibility map reliable.
There's a fair amount left to do here, notably trying to figure out a less
chintzy way of estimating the cost of an index-only scan, but the core
functionality seems ready to commit.
Robert Haas and Ibrar Ahmed, with some previous work by Heikki Linnakangas.
Diffstat (limited to 'src/backend/optimizer/plan/createplan.c')
| -rw-r--r-- | src/backend/optimizer/plan/createplan.c | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/src/backend/optimizer/plan/createplan.c b/src/backend/optimizer/plan/createplan.c index 0dedebaf705..36ee7c5648a 100644 --- a/src/backend/optimizer/plan/createplan.c +++ b/src/backend/optimizer/plan/createplan.c @@ -95,7 +95,7 @@ static SeqScan *make_seqscan(List *qptlist, List *qpqual, Index scanrelid); static IndexScan *make_indexscan(List *qptlist, List *qpqual, Index scanrelid, Oid indexid, List *indexqual, List *indexqualorig, List *indexorderby, List *indexorderbyorig, - ScanDirection indexscandir); + ScanDirection indexscandir, bool indexonly); static BitmapIndexScan *make_bitmap_indexscan(Index scanrelid, Oid indexid, List *indexqual, List *indexqualorig); @@ -1183,7 +1183,8 @@ create_indexscan_plan(PlannerInfo *root, stripped_indexquals, fixed_indexorderbys, indexorderbys, - best_path->indexscandir); + best_path->indexscandir, + best_path->indexonly); copy_path_costsize(&scan_plan->scan.plan, &best_path->path); /* use the indexscan-specific rows estimate, not the parent rel's */ @@ -2841,7 +2842,8 @@ make_indexscan(List *qptlist, List *indexqualorig, List *indexorderby, List *indexorderbyorig, - ScanDirection indexscandir) + ScanDirection indexscandir, + bool indexonly) { IndexScan *node = makeNode(IndexScan); Plan *plan = &node->scan.plan; @@ -2858,6 +2860,7 @@ make_indexscan(List *qptlist, node->indexorderby = indexorderby; node->indexorderbyorig = indexorderbyorig; node->indexorderdir = indexscandir; + node->indexonly = indexonly; return node; } |