diff options
Diffstat (limited to 'src/backend/optimizer/plan/planner.c')
| -rw-r--r-- | src/backend/optimizer/plan/planner.c | 110 |
1 files changed, 6 insertions, 104 deletions
diff --git a/src/backend/optimizer/plan/planner.c b/src/backend/optimizer/plan/planner.c index 5b7fde2533a..c818f0ddf10 100644 --- a/src/backend/optimizer/plan/planner.c +++ b/src/backend/optimizer/plan/planner.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/optimizer/plan/planner.c,v 1.239 2008/08/05 16:03:10 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/optimizer/plan/planner.c,v 1.240 2008/08/07 01:11:50 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -68,10 +68,6 @@ static double preprocess_limit(PlannerInfo *root, double tuple_fraction, int64 *offset_est, int64 *count_est); static void preprocess_groupclause(PlannerInfo *root); -static Oid *extract_grouping_ops(List *groupClause); -static AttrNumber *extract_grouping_cols(List *groupClause, List *tlist); -static bool grouping_is_sortable(List *groupClause); -static bool grouping_is_hashable(List *groupClause); static bool choose_hashed_grouping(PlannerInfo *root, double tuple_fraction, double limit_tuples, Path *cheapest_path, Path *sorted_path, @@ -784,10 +780,9 @@ grouping_planner(PlannerInfo *root, double tuple_fraction) /* * If there's a top-level ORDER BY, assume we have to fetch all the - * tuples. This might seem too simplistic given all the hackery below - * to possibly avoid the sort ... but a nonzero tuple_fraction is only - * of use to plan_set_operations() when the setop is UNION ALL, and - * the result of UNION ALL is always unsorted. + * tuples. This might be too simplistic given all the hackery below + * to possibly avoid the sort; but the odds of accurate estimates + * here are pretty low anyway. */ if (parse->sortClause) tuple_fraction = 0.0; @@ -818,7 +813,8 @@ grouping_planner(PlannerInfo *root, double tuple_fraction) */ Assert(parse->commandType == CMD_SELECT); - tlist = postprocess_setop_tlist(result_plan->targetlist, tlist); + tlist = postprocess_setop_tlist(copyObject(result_plan->targetlist), + tlist); /* * Can't handle FOR UPDATE/SHARE here (parser should have checked @@ -1715,100 +1711,6 @@ preprocess_groupclause(PlannerInfo *root) } /* - * extract_grouping_ops - make an array of the equality operator OIDs - * for a SortGroupClause list - */ -static Oid * -extract_grouping_ops(List *groupClause) -{ - int numCols = list_length(groupClause); - int colno = 0; - Oid *groupOperators; - ListCell *glitem; - - groupOperators = (Oid *) palloc(sizeof(Oid) * numCols); - - foreach(glitem, groupClause) - { - SortGroupClause *groupcl = (SortGroupClause *) lfirst(glitem); - - groupOperators[colno] = groupcl->eqop; - Assert(OidIsValid(groupOperators[colno])); - colno++; - } - - return groupOperators; -} - -/* - * extract_grouping_cols - make an array of the grouping column resnos - * for a SortGroupClause list - */ -static AttrNumber * -extract_grouping_cols(List *groupClause, List *tlist) -{ - AttrNumber *grpColIdx; - int numCols = list_length(groupClause); - int colno = 0; - ListCell *glitem; - - grpColIdx = (AttrNumber *) palloc(sizeof(AttrNumber) * numCols); - - foreach(glitem, groupClause) - { - SortGroupClause *groupcl = (SortGroupClause *) lfirst(glitem); - TargetEntry *tle = get_sortgroupclause_tle(groupcl, tlist); - - grpColIdx[colno++] = tle->resno; - } - - return grpColIdx; -} - -/* - * grouping_is_sortable - is it possible to implement grouping list by sorting? - * - * This is easy since the parser will have included a sortop if one exists. - */ -static bool -grouping_is_sortable(List *groupClause) -{ - ListCell *glitem; - - foreach(glitem, groupClause) - { - SortGroupClause *groupcl = (SortGroupClause *) lfirst(glitem); - - if (!OidIsValid(groupcl->sortop)) - return false; - } - return true; -} - -/* - * grouping_is_hashable - is it possible to implement grouping list by hashing? - * - * We assume hashing is OK if the equality operators are marked oprcanhash. - * (If there isn't actually a supporting hash function, the executor will - * complain at runtime; but this is a misdeclaration of the operator, not - * a system bug.) - */ -static bool -grouping_is_hashable(List *groupClause) -{ - ListCell *glitem; - - foreach(glitem, groupClause) - { - SortGroupClause *groupcl = (SortGroupClause *) lfirst(glitem); - - if (!op_hashjoinable(groupcl->eqop)) - return false; - } - return true; -} - -/* * choose_hashed_grouping - should we use hashed grouping? * * Note: this is only applied when both alternatives are actually feasible. |