diff options
Diffstat (limited to 'src/backend/optimizer/prep/prepunion.c')
| -rw-r--r-- | src/backend/optimizer/prep/prepunion.c | 26 |
1 files changed, 10 insertions, 16 deletions
diff --git a/src/backend/optimizer/prep/prepunion.c b/src/backend/optimizer/prep/prepunion.c index a24e8acfa6c..f87849ea476 100644 --- a/src/backend/optimizer/prep/prepunion.c +++ b/src/backend/optimizer/prep/prepunion.c @@ -711,10 +711,6 @@ generate_nonunion_path(SetOperationStmt *op, PlannerInfo *root, /* Identify the grouping semantics */ groupList = generate_setop_grouplist(op, tlist); - /* punt if nothing to group on (can this happen?) */ - if (groupList == NIL) - return path; - /* * Estimate number of distinct groups that we'll need hashtable entries * for; this is the size of the left-hand input for EXCEPT, or the smaller @@ -741,7 +737,7 @@ generate_nonunion_path(SetOperationStmt *op, PlannerInfo *root, dNumGroups, dNumOutputRows, (op->op == SETOP_INTERSECT) ? "INTERSECT" : "EXCEPT"); - if (!use_hash) + if (groupList && !use_hash) path = (Path *) create_sort_path(root, result_rel, path, @@ -864,10 +860,6 @@ make_union_unique(SetOperationStmt *op, Path *path, List *tlist, /* Identify the grouping semantics */ groupList = generate_setop_grouplist(op, tlist); - /* punt if nothing to group on (can this happen?) */ - if (groupList == NIL) - return path; - /* * XXX for the moment, take the number of distinct groups as equal to the * total input size, ie, the worst case. This is too conservative, but we @@ -898,13 +890,15 @@ make_union_unique(SetOperationStmt *op, Path *path, List *tlist, else { /* Sort and Unique */ - path = (Path *) create_sort_path(root, - result_rel, - path, - make_pathkeys_for_sortclauses(root, - groupList, - tlist), - -1.0); + if (groupList) + path = (Path *) + create_sort_path(root, + result_rel, + path, + make_pathkeys_for_sortclauses(root, + groupList, + tlist), + -1.0); /* We have to manually jam the right tlist into the path; ick */ path->pathtarget = create_pathtarget(root, tlist); path = (Path *) create_upper_unique_path(root, |