diff options
Diffstat (limited to 'src/backend/optimizer/plan/planner.c')
| -rw-r--r-- | src/backend/optimizer/plan/planner.c | 38 |
1 files changed, 36 insertions, 2 deletions
diff --git a/src/backend/optimizer/plan/planner.c b/src/backend/optimizer/plan/planner.c index 2c1081f2677..0e5afccae3a 100644 --- a/src/backend/optimizer/plan/planner.c +++ b/src/backend/optimizer/plan/planner.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/optimizer/plan/planner.c,v 1.131 2002/11/26 03:01:58 tgl Exp $ + * $Header: /cvsroot/pgsql/src/backend/optimizer/plan/planner.c,v 1.132 2002/11/29 21:39:11 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -17,6 +17,7 @@ #include <limits.h> +#include "catalog/pg_operator.h" #include "catalog/pg_type.h" #include "miscadmin.h" #include "nodes/makefuncs.h" @@ -36,9 +37,11 @@ #include "parser/analyze.h" #include "parser/parsetree.h" #include "parser/parse_expr.h" +#include "parser/parse_oper.h" #include "rewrite/rewriteManip.h" #include "utils/lsyscache.h" #include "utils/selfuncs.h" +#include "utils/syscache.h" /* Expression kind codes for preprocess_expression */ @@ -57,6 +60,7 @@ static Node *preprocess_expression(Query *parse, Node *expr, int kind); static void preprocess_qual_conditions(Query *parse, Node *jtnode); static Plan *inheritance_planner(Query *parse, List *inheritlist); static Plan *grouping_planner(Query *parse, double tuple_fraction); +static bool hash_safe_grouping(Query *parse); static List *make_subplanTargetList(Query *parse, List *tlist, AttrNumber **groupColIdx); static Plan *make_groupsortplan(Query *parse, @@ -1252,11 +1256,14 @@ grouping_planner(Query *parse, double tuple_fraction) numGroups = (long) Min(dNumGroups, (double) LONG_MAX); /* + * Check can't-do-it conditions, including whether the grouping + * operators are hashjoinable. + * * Executor doesn't support hashed aggregation with DISTINCT * aggregates. (Doing so would imply storing *all* the input * values in the hash table, which seems like a certain loser.) */ - if (!enable_hashagg) + if (!enable_hashagg || !hash_safe_grouping(parse)) use_hashed_grouping = false; else if (parse->hasAggs && (contain_distinct_agg_clause((Node *) tlist) || @@ -1554,6 +1561,33 @@ grouping_planner(Query *parse, double tuple_fraction) return result_plan; } +/* + * hash_safe_grouping - are grouping operators hashable? + * + * We assume hashed aggregation will work if the datatype's equality operator + * is marked hashjoinable. + */ +static bool +hash_safe_grouping(Query *parse) +{ + List *gl; + + foreach(gl, parse->groupClause) + { + GroupClause *grpcl = (GroupClause *) lfirst(gl); + TargetEntry *tle = get_sortgroupclause_tle(grpcl, parse->targetList); + Operator optup; + bool oprcanhash; + + optup = equality_oper(tle->resdom->restype, false); + oprcanhash = ((Form_pg_operator) GETSTRUCT(optup))->oprcanhash; + ReleaseSysCache(optup); + if (!oprcanhash) + return false; + } + return true; +} + /*--------------- * make_subplanTargetList * Generate appropriate target list when grouping is required. |