From ab46f16a15464e9ba3fae5008ef533e0a6a28303 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Wed, 23 Jul 2025 17:04:45 -0400 Subject: [PATCH v3 1/3] Don't generate fake "*SELECT*" or "*SELECT* %d" subquery aliases. rte->alias should point only to a user-written alias, but in these cases that principle was violated. Fixing this causes some regression test output changes: wherever rte->alias previously had a value and is now NULL, rte->eref is now set to a generated name rather than to rte->alias; and the scheme used to generate eref names differs from what we were doing for aliases. The upshot is that instead of "*SELECT*" or "*SELECT* %d", EXPLAIN will now emit "unnamed_subquery" or "unnamed_subquery_%d". But that's a reasonable descriptor, and we were already producing that in yet other cases, so this seems not too objectionable. Author: Tom Lane Co-authored-by: Robert Haas Discussion: https://postgr.es/m/CA+TgmoYSYmDA2GvanzPMci084n+mVucv0bJ0HPbs6uhmMN6HMg@mail.gmail.com --- contrib/postgres_fdw/expected/postgres_fdw.out | 8 ++++---- src/backend/executor/functions.c | 2 +- src/backend/parser/analyze.c | 7 ++----- src/test/regress/expected/partition_prune.out | 4 ++-- src/test/regress/expected/rangefuncs.out | 8 ++++---- src/test/regress/expected/union.out | 14 +++++++------- 6 files changed, 20 insertions(+), 23 deletions(-) diff --git a/contrib/postgres_fdw/expected/postgres_fdw.out b/contrib/postgres_fdw/expected/postgres_fdw.out index 4b6e49a5d95..c492ba38c58 100644 --- a/contrib/postgres_fdw/expected/postgres_fdw.out +++ b/contrib/postgres_fdw/expected/postgres_fdw.out @@ -5098,13 +5098,13 @@ SELECT ft1.c1 FROM ft1 JOIN ft2 on ft1.c1 = ft2.c1 WHERE -- =================================================================== EXPLAIN (verbose, costs off) INSERT INTO ft2 (c1,c2,c3) SELECT c1+1000,c2+100, c3 || c3 FROM ft2 LIMIT 20; - QUERY PLAN ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- + QUERY PLAN +------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ Insert on public.ft2 Remote SQL: INSERT INTO "S 1"."T 1"("C 1", c2, c3, c4, c5, c6, c7, c8) VALUES ($1, $2, $3, $4, $5, $6, $7, $8) Batch Size: 1 - -> Subquery Scan on "*SELECT*" - Output: "*SELECT*"."?column?", "*SELECT*"."?column?_1", NULL::integer, "*SELECT*"."?column?_2", NULL::timestamp with time zone, NULL::timestamp without time zone, NULL::character varying(10), 'ft2 '::character(10), NULL::user_enum + -> Subquery Scan on unnamed_subquery + Output: unnamed_subquery."?column?", unnamed_subquery."?column?_1", NULL::integer, unnamed_subquery."?column?_2", NULL::timestamp with time zone, NULL::timestamp without time zone, NULL::character varying(10), 'ft2 '::character(10), NULL::user_enum -> Foreign Scan on public.ft2 ft2_1 Output: (ft2_1.c1 + 1000), (ft2_1.c2 + 100), (ft2_1.c3 || ft2_1.c3) Remote SQL: SELECT "C 1", c2, c3 FROM "S 1"."T 1" LIMIT 20::bigint diff --git a/src/backend/executor/functions.c b/src/backend/executor/functions.c index 359aafea681..0547fda2101 100644 --- a/src/backend/executor/functions.c +++ b/src/backend/executor/functions.c @@ -2454,7 +2454,7 @@ tlist_coercion_finished: rte = makeNode(RangeTblEntry); rte->rtekind = RTE_SUBQUERY; rte->subquery = parse; - rte->eref = rte->alias = makeAlias("*SELECT*", colnames); + rte->eref = makeAlias("unnamed_subquery", colnames); rte->lateral = false; rte->inh = false; rte->inFromCl = true; diff --git a/src/backend/parser/analyze.c b/src/backend/parser/analyze.c index 34f7c17f576..b9763ea1714 100644 --- a/src/backend/parser/analyze.c +++ b/src/backend/parser/analyze.c @@ -777,7 +777,7 @@ transformInsertStmt(ParseState *pstate, InsertStmt *stmt) */ nsitem = addRangeTableEntryForSubquery(pstate, selectQuery, - makeAlias("*SELECT*", NIL), + NULL, false, false); addNSItemToQuery(pstate, nsitem, true, false, false); @@ -2100,7 +2100,6 @@ transformSetOperationTree(ParseState *pstate, SelectStmt *stmt, { /* Process leaf SELECT */ Query *selectQuery; - char selectName[32]; ParseNamespaceItem *nsitem; RangeTblRef *rtr; ListCell *tl; @@ -2156,11 +2155,9 @@ transformSetOperationTree(ParseState *pstate, SelectStmt *stmt, /* * Make the leaf query be a subquery in the top-level rangetable. */ - snprintf(selectName, sizeof(selectName), "*SELECT* %d", - list_length(pstate->p_rtable) + 1); nsitem = addRangeTableEntryForSubquery(pstate, selectQuery, - makeAlias(selectName, NIL), + NULL, false, false); diff --git a/src/test/regress/expected/partition_prune.out b/src/test/regress/expected/partition_prune.out index d1966cd7d82..68ecd951809 100644 --- a/src/test/regress/expected/partition_prune.out +++ b/src/test/regress/expected/partition_prune.out @@ -4763,7 +4763,7 @@ select min(a) over (partition by a order by a) from part_abc where a >= stable_o QUERY PLAN ---------------------------------------------------------------------------------------------- Append - -> Subquery Scan on "*SELECT* 1_1" + -> Subquery Scan on unnamed_subquery_2 -> WindowAgg Window: w1 AS (PARTITION BY part_abc.a ORDER BY part_abc.a) -> Append @@ -4780,7 +4780,7 @@ select min(a) over (partition by a order by a) from part_abc where a >= stable_o -> Index Scan using part_abc_3_2_a_idx on part_abc_3_2 part_abc_4 Index Cond: (a >= (stable_one() + 1)) Filter: (d <= stable_one()) - -> Subquery Scan on "*SELECT* 2" + -> Subquery Scan on unnamed_subquery_1 -> WindowAgg Window: w1 AS (PARTITION BY part_abc_5.a ORDER BY part_abc_5.a) -> Append diff --git a/src/test/regress/expected/rangefuncs.out b/src/test/regress/expected/rangefuncs.out index c21be83aa4a..30241e22da2 100644 --- a/src/test/regress/expected/rangefuncs.out +++ b/src/test/regress/expected/rangefuncs.out @@ -2130,10 +2130,10 @@ select testrngfunc(); explain (verbose, costs off) select * from testrngfunc(); - QUERY PLAN ----------------------------------------------------------- - Subquery Scan on "*SELECT*" - Output: "*SELECT*"."?column?", "*SELECT*"."?column?_1" + QUERY PLAN +---------------------------------------------------------------------- + Subquery Scan on unnamed_subquery + Output: unnamed_subquery."?column?", unnamed_subquery."?column?_1" -> Unique Output: (1), (2) -> Sort diff --git a/src/test/regress/expected/union.out b/src/test/regress/expected/union.out index 96962817ed4..d3ea433db15 100644 --- a/src/test/regress/expected/union.out +++ b/src/test/regress/expected/union.out @@ -942,7 +942,7 @@ SELECT q1 FROM int8_tbl EXCEPT SELECT q2 FROM int8_tbl ORDER BY q2 LIMIT 1; ERROR: column "q2" does not exist LINE 1: ... int8_tbl EXCEPT SELECT q2 FROM int8_tbl ORDER BY q2 LIMIT 1... ^ -DETAIL: There is a column named "q2" in table "*SELECT* 2", but it cannot be referenced from this part of the query. +DETAIL: There is a column named "q2" in table "unnamed_subquery", but it cannot be referenced from this part of the query. -- But this should work: SELECT q1 FROM int8_tbl EXCEPT (((SELECT q2 FROM int8_tbl ORDER BY q2 LIMIT 1))) ORDER BY 1; q1 @@ -1338,14 +1338,14 @@ where q2 = q2; ---------------------------------------------------------- Unique -> Merge Append - Sort Key: "*SELECT* 1".q1 - -> Subquery Scan on "*SELECT* 1" + Sort Key: unnamed_subquery.q1 + -> Subquery Scan on unnamed_subquery -> Unique -> Sort Sort Key: i81.q1, i81.q2 -> Seq Scan on int8_tbl i81 Filter: (q2 IS NOT NULL) - -> Subquery Scan on "*SELECT* 2" + -> Subquery Scan on unnamed_subquery_1 -> Unique -> Sort Sort Key: i82.q1, i82.q2 @@ -1374,14 +1374,14 @@ where -q1 = q2; -------------------------------------------------------- Unique -> Merge Append - Sort Key: "*SELECT* 1".q1 - -> Subquery Scan on "*SELECT* 1" + Sort Key: unnamed_subquery.q1 + -> Subquery Scan on unnamed_subquery -> Unique -> Sort Sort Key: i81.q1, i81.q2 -> Seq Scan on int8_tbl i81 Filter: ((- q1) = q2) - -> Subquery Scan on "*SELECT* 2" + -> Subquery Scan on unnamed_subquery_1 -> Unique -> Sort Sort Key: i82.q1, i82.q2 -- 2.43.5