diff options
Diffstat (limited to 'src/backend/optimizer/plan/planner.c')
| -rw-r--r-- | src/backend/optimizer/plan/planner.c | 53 |
1 files changed, 49 insertions, 4 deletions
diff --git a/src/backend/optimizer/plan/planner.c b/src/backend/optimizer/plan/planner.c index 5951e8f0c9b..67089e68d29 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 1.94 2000/11/05 00:15:53 tgl Exp $ + * $Header: /cvsroot/pgsql/src/backend/optimizer/plan/planner.c,v 1.95 2000/11/09 02:46:16 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -48,6 +48,8 @@ static List *make_subplanTargetList(Query *parse, List *tlist, static Plan *make_groupplan(List *group_tlist, bool tuplePerGroup, List *groupClause, AttrNumber *grpColIdx, bool is_presorted, Plan *subplan); +static List *postprocess_setop_tlist(List *new_tlist, List *orig_tlist); + /***************************************************************************** * @@ -635,17 +637,22 @@ union_planner(Query *parse, if (parse->setOperations) { /* - * Construct the plan for set operations. The result will - * not need any work except perhaps a top-level sort. + * Construct the plan for set operations. The result will not + * need any work except perhaps a top-level sort and/or LIMIT. */ result_plan = plan_set_operations(parse); /* * We should not need to call preprocess_targetlist, since we must - * be in a SELECT query node. + * be in a SELECT query node. Instead, use the targetlist + * returned by plan_set_operations (since this tells whether it + * returned any resjunk columns!), and transfer any sort key + * information from the original tlist. */ Assert(parse->commandType == CMD_SELECT); + tlist = postprocess_setop_tlist(result_plan->targetlist, tlist); + /* * We leave current_pathkeys NIL indicating we do not know sort * order. This is correct when the top set operation is UNION ALL, @@ -1255,3 +1262,41 @@ make_sortplan(List *tlist, Plan *plannode, List *sortcls) return (Plan *) make_sort(sort_tlist, plannode, keyno); } + +/* + * postprocess_setop_tlist + * Fix up targetlist returned by plan_set_operations(). + * + * We need to transpose sort key info from the orig_tlist into new_tlist. + * NOTE: this would not be good enough if we supported resjunk sort keys + * for results of set operations --- then, we'd need to project a whole + * new tlist to evaluate the resjunk columns. For now, just elog if we + * find any resjunk columns in orig_tlist. + */ +static List * +postprocess_setop_tlist(List *new_tlist, List *orig_tlist) +{ + List *l; + + foreach(l, new_tlist) + { + TargetEntry *new_tle = (TargetEntry *) lfirst(l); + TargetEntry *orig_tle; + + /* ignore resjunk columns in setop result */ + if (new_tle->resdom->resjunk) + continue; + + Assert(orig_tlist != NIL); + orig_tle = (TargetEntry *) lfirst(orig_tlist); + orig_tlist = lnext(orig_tlist); + if (orig_tle->resdom->resjunk) + elog(ERROR, "postprocess_setop_tlist: resjunk output columns not implemented"); + Assert(new_tle->resdom->resno == orig_tle->resdom->resno); + Assert(new_tle->resdom->restype == orig_tle->resdom->restype); + new_tle->resdom->ressortgroupref = orig_tle->resdom->ressortgroupref; + } + if (orig_tlist != NIL) + elog(ERROR, "postprocess_setop_tlist: resjunk output columns not implemented"); + return new_tlist; +} |