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| author | Tom Lane <tgl@sss.pgh.pa.us> | 2007-05-21 17:57:35 +0000 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2007-05-21 17:57:35 +0000 |
| commit | 2415ad983174164ff30ce487c0e6b4b53321b83a (patch) | |
| tree | 8f3bae7fd588a6cfa9bcaf33e6e5ea5f1cf89a4d /src/include/optimizer | |
| parent | 3963574d13383b4f377ab054e47e4af20cb75e7d (diff) | |
| download | postgresql-2415ad983174164ff30ce487c0e6b4b53321b83a.tar.gz | |
Teach tuplestore.c to throw away data before the "mark" point when the caller
is using mark/restore but not rewind or backward-scan capability. Insert a
materialize plan node between a mergejoin and its inner child if the inner
child is a sort that is expected to spill to disk. The materialize shields
the sort from the need to do mark/restore and thereby allows it to perform
its final merge pass on-the-fly; while the materialize itself is normally
cheap since it won't spill to disk unless the number of tuples with equal
key values exceeds work_mem.
Greg Stark, with some kibitzing from Tom Lane.
Diffstat (limited to 'src/include/optimizer')
| -rw-r--r-- | src/include/optimizer/cost.h | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/src/include/optimizer/cost.h b/src/include/optimizer/cost.h index 641555b706..138741e07a 100644 --- a/src/include/optimizer/cost.h +++ b/src/include/optimizer/cost.h @@ -7,7 +7,7 @@ * Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * - * $PostgreSQL: pgsql/src/include/optimizer/cost.h,v 1.86 2007/05/04 01:13:45 tgl Exp $ + * $PostgreSQL: pgsql/src/include/optimizer/cost.h,v 1.87 2007/05/21 17:57:34 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -75,6 +75,7 @@ extern void cost_valuesscan(Path *path, PlannerInfo *root, extern void cost_sort(Path *path, PlannerInfo *root, List *pathkeys, Cost input_cost, double tuples, int width, double limit_tuples); +extern bool sort_exceeds_work_mem(Sort *sort); extern void cost_material(Path *path, Cost input_cost, double tuples, int width); extern void cost_agg(Path *path, PlannerInfo *root, |