diff options
Diffstat (limited to 'src/backend/optimizer/plan/planmain.c')
| -rw-r--r-- | src/backend/optimizer/plan/planmain.c | 37 |
1 files changed, 26 insertions, 11 deletions
diff --git a/src/backend/optimizer/plan/planmain.c b/src/backend/optimizer/plan/planmain.c index d26e3eb8b49..8691215b466 100644 --- a/src/backend/optimizer/plan/planmain.c +++ b/src/backend/optimizer/plan/planmain.c @@ -7,7 +7,7 @@ * * * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/optimizer/plan/planmain.c,v 1.12 1997/12/20 07:59:25 momjian Exp $ + * $Header: /cvsroot/pgsql/src/backend/optimizer/plan/planmain.c,v 1.13 1997/12/22 05:42:04 momjian Exp $ * *------------------------------------------------------------------------- */ @@ -69,7 +69,7 @@ query_planner(Query *root, List *qual) { List *constant_qual = NIL; - List *flattened_tlist = NIL; + List *var_only_tlist = NIL; List *level_tlist = NIL; Plan *subplan = (Plan *) NULL; @@ -109,16 +109,12 @@ query_planner(Query *root, * Create a target list that consists solely of (resdom var) target * list entries, i.e., contains no arbitrary expressions. */ - flattened_tlist = flatten_tlist(tlist); - if (flattened_tlist) - { - level_tlist = flattened_tlist; - } + var_only_tlist = flatten_tlist(tlist); + if (var_only_tlist) + level_tlist = var_only_tlist; else - { /* from old code. the logic is beyond me. - ay 2/95 */ level_tlist = tlist; - } /* * A query may have a non-variable target list and a non-variable @@ -126,7 +122,7 @@ query_planner(Query *root, * all-new tuples, or - the query is a replace (a scan must still be * done in this case). */ - if (flattened_tlist == NULL && qual == NULL) + if (var_only_tlist == NULL && qual == NULL) { switch (command_type) @@ -193,10 +189,29 @@ query_planner(Query *root, } /* + * fix up the flattened target list of the plan root node so that + * expressions are evaluated. this forces expression evaluations that + * may involve expensive function calls to be delayed to the very last + * stage of query execution. this could be bad. but it is joey's + * responsibility to optimally push these expressions down the plan + * tree. -- Wei + * + * But now nothing to do if there are GroupBy and/or Aggregates: 1. + * make_groupPlan fixes tlist; 2. flatten_tlist_vars does nothing with + * aggregates fixing only other entries (i.e. - GroupBy-ed and so + * fixed by make_groupPlan). - vadim 04/05/97 + */ + if (root->groupClause == NULL && root->qry_aggs == NULL) + { + subplan->targetlist = flatten_tlist_vars(tlist, + subplan->targetlist); + } + +#ifdef NOT_USED + /* * Destructively modify the query plan's targetlist to add fjoin lists * to flatten functions that return sets of base types */ -#ifdef NOT_USED subplan->targetlist = generate_fjoin(subplan->targetlist); #endif |