diff options
Diffstat (limited to 'src/backend/optimizer/path')
| -rw-r--r-- | src/backend/optimizer/path/costsize.c | 35 | ||||
| -rw-r--r-- | src/backend/optimizer/path/joinrels.c | 4 |
2 files changed, 35 insertions, 4 deletions
diff --git a/src/backend/optimizer/path/costsize.c b/src/backend/optimizer/path/costsize.c index cc9e49b9e22..8e88e46d571 100644 --- a/src/backend/optimizer/path/costsize.c +++ b/src/backend/optimizer/path/costsize.c @@ -41,7 +41,7 @@ * Portions Copyright (c) 1994, Regents of the University of California * * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/optimizer/path/costsize.c,v 1.67 2001/02/15 17:46:40 tgl Exp $ + * $Header: /cvsroot/pgsql/src/backend/optimizer/path/costsize.c,v 1.68 2001/02/16 00:03:07 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -837,11 +837,12 @@ void set_joinrel_size_estimates(Query *root, RelOptInfo *rel, RelOptInfo *outer_rel, RelOptInfo *inner_rel, + JoinType jointype, List *restrictlist) { double temp; - /* cartesian product */ + /* Start with the Cartesian product */ temp = outer_rel->rows * inner_rel->rows; /* @@ -855,12 +856,42 @@ set_joinrel_size_estimates(Query *root, RelOptInfo *rel, 0); /* + * If we are doing an outer join, take that into account: the output + * must be at least as large as the non-nullable input. (Is there any + * chance of being even smarter?) + */ + switch (jointype) + { + case JOIN_INNER: + break; + case JOIN_LEFT: + if (temp < outer_rel->rows) + temp = outer_rel->rows; + break; + case JOIN_RIGHT: + if (temp < inner_rel->rows) + temp = inner_rel->rows; + break; + case JOIN_FULL: + if (temp < outer_rel->rows) + temp = outer_rel->rows; + if (temp < inner_rel->rows) + temp = inner_rel->rows; + break; + default: + elog(ERROR, "set_joinrel_size_estimates: unsupported join type %d", + (int) jointype); + break; + } + + /* * Force estimate to be at least one row, to make explain output look * better and to avoid possible divide-by-zero when interpolating * cost. */ if (temp < 1.0) temp = 1.0; + rel->rows = temp; /* diff --git a/src/backend/optimizer/path/joinrels.c b/src/backend/optimizer/path/joinrels.c index 2a59ed43e48..2492f17ea9b 100644 --- a/src/backend/optimizer/path/joinrels.c +++ b/src/backend/optimizer/path/joinrels.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/optimizer/path/joinrels.c,v 1.50 2001/01/24 19:42:58 momjian Exp $ + * $Header: /cvsroot/pgsql/src/backend/optimizer/path/joinrels.c,v 1.51 2001/02/16 00:03:07 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -394,7 +394,7 @@ make_join_rel(Query *root, RelOptInfo *rel1, RelOptInfo *rel2, * Find or build the join RelOptInfo, and compute the restrictlist * that goes with this particular joining. */ - joinrel = get_join_rel(root, rel1, rel2, &restrictlist); + joinrel = get_join_rel(root, rel1, rel2, jointype, &restrictlist); /* * Consider paths using each rel as both outer and inner. |