diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/backend/optimizer/plan/createplan.c | 15 | ||||
| -rw-r--r-- | src/backend/optimizer/util/tlist.c | 23 | ||||
| -rw-r--r-- | src/test/regress/expected/select_distinct.out | 24 | ||||
| -rw-r--r-- | src/test/regress/sql/select_distinct.sql | 11 |
4 files changed, 65 insertions, 8 deletions
diff --git a/src/backend/optimizer/plan/createplan.c b/src/backend/optimizer/plan/createplan.c index 185f0625a78..bd19f43d586 100644 --- a/src/backend/optimizer/plan/createplan.c +++ b/src/backend/optimizer/plan/createplan.c @@ -787,10 +787,14 @@ use_physical_tlist(PlannerInfo *root, Path *path, int flags) * to emit any sort/group columns that are not simple Vars. (If they are * simple Vars, they should appear in the physical tlist, and * apply_pathtarget_labeling_to_tlist will take care of getting them - * labeled again.) + * labeled again.) We also have to check that no two sort/group columns + * are the same Var, else that element of the physical tlist would need + * conflicting ressortgroupref labels. */ if ((flags & CP_LABEL_TLIST) && path->pathtarget->sortgrouprefs) { + Bitmapset *sortgroupatts = NULL; + i = 0; foreach(lc, path->pathtarget->exprs) { @@ -799,7 +803,14 @@ use_physical_tlist(PlannerInfo *root, Path *path, int flags) if (path->pathtarget->sortgrouprefs[i]) { if (expr && IsA(expr, Var)) - /* okay */ ; + { + int attno = ((Var *) expr)->varattno; + + attno -= FirstLowInvalidHeapAttributeNumber; + if (bms_is_member(attno, sortgroupatts)) + return false; + sortgroupatts = bms_add_member(sortgroupatts, attno); + } else return false; } diff --git a/src/backend/optimizer/util/tlist.c b/src/backend/optimizer/util/tlist.c index aa2c2f890c0..94825408b2a 100644 --- a/src/backend/optimizer/util/tlist.c +++ b/src/backend/optimizer/util/tlist.c @@ -736,17 +736,28 @@ apply_pathtarget_labeling_to_tlist(List *tlist, PathTarget *target) * this allows us to deal with some cases where a set-returning * function has been inlined, so that we now have more knowledge * about what it returns than we did when the original Var was - * created. Otherwise, use regular equal() to see if there's a - * matching TLE. (In current usage, only the Var case is actually - * needed; but it seems best to have sane behavior here for - * non-Vars too.) + * created. Otherwise, use regular equal() to find the matching + * TLE. (In current usage, only the Var case is actually needed; + * but it seems best to have sane behavior here for non-Vars too.) */ if (expr && IsA(expr, Var)) tle = tlist_member_match_var((Var *) expr, tlist); else tle = tlist_member((Node *) expr, tlist); - if (tle) - tle->ressortgroupref = target->sortgrouprefs[i]; + + /* + * Complain if noplace for the sortgrouprefs label, or if we'd + * have to label a column twice. (The case where it already has + * the desired label probably can't happen, but we may as well + * allow for it.) + */ + if (!tle) + elog(ERROR, "ORDER/GROUP BY expression not found in targetlist"); + if (tle->ressortgroupref != 0 && + tle->ressortgroupref != target->sortgrouprefs[i]) + elog(ERROR, "targetlist item has multiple sortgroupref labels"); + + tle->ressortgroupref = target->sortgrouprefs[i]; } i++; } diff --git a/src/test/regress/expected/select_distinct.out b/src/test/regress/expected/select_distinct.out index 38107a04133..f3696c6d1de 100644 --- a/src/test/regress/expected/select_distinct.out +++ b/src/test/regress/expected/select_distinct.out @@ -125,6 +125,30 @@ SELECT DISTINCT p.age FROM person* p ORDER BY age using >; (20 rows) -- +-- Check mentioning same column more than once +-- +EXPLAIN (VERBOSE, COSTS OFF) +SELECT count(*) FROM + (SELECT DISTINCT two, four, two FROM tenk1) ss; + QUERY PLAN +-------------------------------------------------------- + Aggregate + Output: count(*) + -> HashAggregate + Output: tenk1.two, tenk1.four, tenk1.two + Group Key: tenk1.two, tenk1.four, tenk1.two + -> Seq Scan on public.tenk1 + Output: tenk1.two, tenk1.four, tenk1.two +(7 rows) + +SELECT count(*) FROM + (SELECT DISTINCT two, four, two FROM tenk1) ss; + count +------- + 4 +(1 row) + +-- -- Also, some tests of IS DISTINCT FROM, which doesn't quite deserve its -- very own regression file. -- diff --git a/src/test/regress/sql/select_distinct.sql b/src/test/regress/sql/select_distinct.sql index 328ba51c7a8..a605e86449e 100644 --- a/src/test/regress/sql/select_distinct.sql +++ b/src/test/regress/sql/select_distinct.sql @@ -35,6 +35,17 @@ SELECT DISTINCT two, string4, ten SELECT DISTINCT p.age FROM person* p ORDER BY age using >; -- +-- Check mentioning same column more than once +-- + +EXPLAIN (VERBOSE, COSTS OFF) +SELECT count(*) FROM + (SELECT DISTINCT two, four, two FROM tenk1) ss; + +SELECT count(*) FROM + (SELECT DISTINCT two, four, two FROM tenk1) ss; + +-- -- Also, some tests of IS DISTINCT FROM, which doesn't quite deserve its -- very own regression file. -- |