diff --git a/src/backend/optimizer/util/clauses.c b/src/backend/optimizer/util/clauses.c index 26a3e0500866..c15a3a41cb64 100644 --- a/src/backend/optimizer/util/clauses.c +++ b/src/backend/optimizer/util/clauses.c @@ -3333,6 +3333,13 @@ eval_const_expressions_mutator(Node *node, -1, coalesceexpr->coalescecollid); + /* + * COALESCE with single valued argument looks like identity + * function so that it's converged to its single argument + */ + if (list_length(newargs) == 1) + return (Node *) linitial(newargs); + newcoalesce = makeNode(CoalesceExpr); newcoalesce->coalescetype = coalesceexpr->coalescetype; newcoalesce->coalescecollid = coalesceexpr->coalescecollid; diff --git a/src/test/regress/expected/join.out b/src/test/regress/expected/join.out index f35a0b18c37c..2501c26079f1 100644 --- a/src/test/regress/expected/join.out +++ b/src/test/regress/expected/join.out @@ -5384,14 +5384,14 @@ select * from (select 1 as id) as xx left join (tenk1 as a1 full join (select 1 as id) as yy on (a1.unique1 = yy.id)) - on (xx.id = coalesce(yy.id)); - QUERY PLAN ---------------------------------------- + on (xx.id = coalesce(yy.id, 0)); + QUERY PLAN +---------------------------------------- Nested Loop Left Join -> Result -> Hash Full Join Hash Cond: (a1.unique1 = (1)) - Filter: (1 = COALESCE((1))) + Filter: (1 = COALESCE((1), 0)) -> Seq Scan on tenk1 a1 -> Hash -> Result @@ -5401,7 +5401,7 @@ select * from (select 1 as id) as xx left join (tenk1 as a1 full join (select 1 as id) as yy on (a1.unique1 = yy.id)) - on (xx.id = coalesce(yy.id)); + on (xx.id = coalesce(yy.id, 0)); id | unique1 | unique2 | two | four | ten | twenty | hundred | thousand | twothousand | fivethous | tenthous | odd | even | stringu1 | stringu2 | string4 | id ----+---------+---------+-----+------+-----+--------+---------+----------+-------------+-----------+----------+-----+------+----------+----------+---------+---- 1 | 1 | 2838 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 2 | 3 | BAAAAA | EFEAAA | OOOOxx | 1 @@ -8169,20 +8169,20 @@ select * from int4_tbl i left join explain (verbose, costs off) select * from int4_tbl i left join - lateral (select coalesce(i) from int2_tbl j where i.f1 = j.f1) k on true; - QUERY PLAN -------------------------------------- + lateral (select coalesce(i, row(0)::int4_tbl) from int2_tbl j where i.f1 = j.f1) k on true; + QUERY PLAN +------------------------------------------------------ Nested Loop Left Join - Output: i.f1, (COALESCE(i.*)) + Output: i.f1, (COALESCE(i.*, '(0)'::int4_tbl)) -> Seq Scan on public.int4_tbl i Output: i.f1, i.* -> Seq Scan on public.int2_tbl j - Output: j.f1, COALESCE(i.*) + Output: j.f1, COALESCE(i.*, '(0)'::int4_tbl) Filter: (i.f1 = j.f1) (7 rows) select * from int4_tbl i left join - lateral (select coalesce(i) from int2_tbl j where i.f1 = j.f1) k on true; + lateral (select coalesce(i, row(0)::int4_tbl) from int2_tbl j where i.f1 = j.f1) k on true; f1 | coalesce -------------+---------- 0 | (0) @@ -9351,14 +9351,14 @@ CREATE STATISTICS group_tbl_stat (ndistinct) ON a, b FROM group_tbl; ANALYZE group_tbl; EXPLAIN (COSTS OFF) SELECT 1 FROM group_tbl t1 - LEFT JOIN (SELECT a c1, COALESCE(a) c2 FROM group_tbl t2) s ON TRUE + LEFT JOIN (SELECT a c1, COALESCE(a, 0) c2 FROM group_tbl t2) s ON TRUE GROUP BY s.c1, s.c2; - QUERY PLAN --------------------------------------------- + QUERY PLAN +--------------------------------------------- Group - Group Key: t2.a, (COALESCE(t2.a)) + Group Key: t2.a, (COALESCE(t2.a, 0)) -> Sort - Sort Key: t2.a, (COALESCE(t2.a)) + Sort Key: t2.a, (COALESCE(t2.a, 0)) -> Nested Loop Left Join -> Seq Scan on group_tbl t1 -> Seq Scan on group_tbl t2 diff --git a/src/test/regress/expected/subselect.out b/src/test/regress/expected/subselect.out index 40d8056fcea4..8af48e2ce13b 100644 --- a/src/test/regress/expected/subselect.out +++ b/src/test/regress/expected/subselect.out @@ -2127,30 +2127,30 @@ explain (verbose, costs off) select ss2.* from int8_tbl t1 left join (int8_tbl t2 left join - (select coalesce(q1) as x, * from int8_tbl t3) ss1 on t2.q1 = ss1.q2 inner join + (select coalesce(q1, 0) as x, * from int8_tbl t3) ss1 on t2.q1 = ss1.q2 inner join lateral (select ss1.x as y, * from int8_tbl t4) ss2 on t2.q2 = ss2.q1) on t1.q2 = ss2.q1 order by 1, 2, 3; - QUERY PLAN ----------------------------------------------------------------- + QUERY PLAN +----------------------------------------------------------------------------- Sort - Output: (COALESCE(t3.q1)), t4.q1, t4.q2 - Sort Key: (COALESCE(t3.q1)), t4.q1, t4.q2 + Output: (COALESCE(t3.q1, '0'::bigint)), t4.q1, t4.q2 + Sort Key: (COALESCE(t3.q1, '0'::bigint)), t4.q1, t4.q2 -> Hash Right Join - Output: (COALESCE(t3.q1)), t4.q1, t4.q2 + Output: (COALESCE(t3.q1, '0'::bigint)), t4.q1, t4.q2 Hash Cond: (t4.q1 = t1.q2) -> Hash Join - Output: (COALESCE(t3.q1)), t4.q1, t4.q2 + Output: (COALESCE(t3.q1, '0'::bigint)), t4.q1, t4.q2 Hash Cond: (t2.q2 = t4.q1) -> Hash Left Join - Output: t2.q2, (COALESCE(t3.q1)) + Output: t2.q2, (COALESCE(t3.q1, '0'::bigint)) Hash Cond: (t2.q1 = t3.q2) -> Seq Scan on public.int8_tbl t2 Output: t2.q1, t2.q2 -> Hash - Output: t3.q2, (COALESCE(t3.q1)) + Output: t3.q2, (COALESCE(t3.q1, '0'::bigint)) -> Seq Scan on public.int8_tbl t3 - Output: t3.q2, COALESCE(t3.q1) + Output: t3.q2, COALESCE(t3.q1, '0'::bigint) -> Hash Output: t4.q1, t4.q2 -> Seq Scan on public.int8_tbl t4 @@ -2164,7 +2164,7 @@ order by 1, 2, 3; select ss2.* from int8_tbl t1 left join (int8_tbl t2 left join - (select coalesce(q1) as x, * from int8_tbl t3) ss1 on t2.q1 = ss1.q2 inner join + (select coalesce(q1, 0) as x, * from int8_tbl t3) ss1 on t2.q1 = ss1.q2 inner join lateral (select ss1.x as y, * from int8_tbl t4) ss2 on t2.q2 = ss2.q1) on t1.q2 = ss2.q1 order by 1, 2, 3; @@ -2201,32 +2201,32 @@ explain (verbose, costs off) select ss2.* from int8_tbl t1 left join (int8_tbl t2 left join - (select coalesce(q1) as x, * from int8_tbl t3) ss1 on t2.q1 = ss1.q2 left join + (select coalesce(q1, 0) as x, * from int8_tbl t3) ss1 on t2.q1 = ss1.q2 left join lateral (select ss1.x as y, * from int8_tbl t4) ss2 on t2.q2 = ss2.q1) on t1.q2 = ss2.q1 order by 1, 2, 3; - QUERY PLAN ----------------------------------------------------------------- + QUERY PLAN +----------------------------------------------------------------------------- Sort - Output: ((COALESCE(t3.q1))), t4.q1, t4.q2 - Sort Key: ((COALESCE(t3.q1))), t4.q1, t4.q2 + Output: ((COALESCE(t3.q1, '0'::bigint))), t4.q1, t4.q2 + Sort Key: ((COALESCE(t3.q1, '0'::bigint))), t4.q1, t4.q2 -> Hash Right Join - Output: ((COALESCE(t3.q1))), t4.q1, t4.q2 + Output: ((COALESCE(t3.q1, '0'::bigint))), t4.q1, t4.q2 Hash Cond: (t4.q1 = t1.q2) -> Nested Loop - Output: t4.q1, t4.q2, ((COALESCE(t3.q1))) + Output: t4.q1, t4.q2, ((COALESCE(t3.q1, '0'::bigint))) Join Filter: (t2.q2 = t4.q1) -> Hash Left Join - Output: t2.q2, (COALESCE(t3.q1)) + Output: t2.q2, (COALESCE(t3.q1, '0'::bigint)) Hash Cond: (t2.q1 = t3.q2) -> Seq Scan on public.int8_tbl t2 Output: t2.q1, t2.q2 -> Hash - Output: t3.q2, (COALESCE(t3.q1)) + Output: t3.q2, (COALESCE(t3.q1, '0'::bigint)) -> Seq Scan on public.int8_tbl t3 - Output: t3.q2, COALESCE(t3.q1) + Output: t3.q2, COALESCE(t3.q1, '0'::bigint) -> Seq Scan on public.int8_tbl t4 - Output: t4.q1, t4.q2, (COALESCE(t3.q1)) + Output: t4.q1, t4.q2, (COALESCE(t3.q1, '0'::bigint)) -> Hash Output: t1.q2 -> Seq Scan on public.int8_tbl t1 @@ -2236,7 +2236,7 @@ order by 1, 2, 3; select ss2.* from int8_tbl t1 left join (int8_tbl t2 left join - (select coalesce(q1) as x, * from int8_tbl t3) ss1 on t2.q1 = ss1.q2 left join + (select coalesce(q1, 0) as x, * from int8_tbl t3) ss1 on t2.q1 = ss1.q2 left join lateral (select ss1.x as y, * from int8_tbl t4) ss2 on t2.q2 = ss2.q1) on t1.q2 = ss2.q1 order by 1, 2, 3; diff --git a/src/test/regress/sql/join.sql b/src/test/regress/sql/join.sql index cc5128add4df..b00835976d77 100644 --- a/src/test/regress/sql/join.sql +++ b/src/test/regress/sql/join.sql @@ -1902,13 +1902,13 @@ select * from (select 1 as id) as xx left join (tenk1 as a1 full join (select 1 as id) as yy on (a1.unique1 = yy.id)) - on (xx.id = coalesce(yy.id)); + on (xx.id = coalesce(yy.id, 0)); select * from (select 1 as id) as xx left join (tenk1 as a1 full join (select 1 as id) as yy on (a1.unique1 = yy.id)) - on (xx.id = coalesce(yy.id)); + on (xx.id = coalesce(yy.id, 0)); -- -- test ability to push constants through outer join clauses @@ -3094,9 +3094,9 @@ select * from int4_tbl i left join lateral (select * from int2_tbl j where i.f1 = j.f1) k on true; explain (verbose, costs off) select * from int4_tbl i left join - lateral (select coalesce(i) from int2_tbl j where i.f1 = j.f1) k on true; + lateral (select coalesce(i, row(0)::int4_tbl) from int2_tbl j where i.f1 = j.f1) k on true; select * from int4_tbl i left join - lateral (select coalesce(i) from int2_tbl j where i.f1 = j.f1) k on true; + lateral (select coalesce(i, row(0)::int4_tbl) from int2_tbl j where i.f1 = j.f1) k on true; explain (verbose, costs off) select * from int4_tbl a, lateral ( @@ -3562,7 +3562,7 @@ ANALYZE group_tbl; EXPLAIN (COSTS OFF) SELECT 1 FROM group_tbl t1 - LEFT JOIN (SELECT a c1, COALESCE(a) c2 FROM group_tbl t2) s ON TRUE + LEFT JOIN (SELECT a c1, COALESCE(a, 0) c2 FROM group_tbl t2) s ON TRUE GROUP BY s.c1, s.c2; DROP TABLE group_tbl; diff --git a/src/test/regress/sql/subselect.sql b/src/test/regress/sql/subselect.sql index fec38ef85a6a..2cff59e6912d 100644 --- a/src/test/regress/sql/subselect.sql +++ b/src/test/regress/sql/subselect.sql @@ -1041,7 +1041,7 @@ explain (verbose, costs off) select ss2.* from int8_tbl t1 left join (int8_tbl t2 left join - (select coalesce(q1) as x, * from int8_tbl t3) ss1 on t2.q1 = ss1.q2 inner join + (select coalesce(q1, 0) as x, * from int8_tbl t3) ss1 on t2.q1 = ss1.q2 inner join lateral (select ss1.x as y, * from int8_tbl t4) ss2 on t2.q2 = ss2.q1) on t1.q2 = ss2.q1 order by 1, 2, 3; @@ -1049,7 +1049,7 @@ order by 1, 2, 3; select ss2.* from int8_tbl t1 left join (int8_tbl t2 left join - (select coalesce(q1) as x, * from int8_tbl t3) ss1 on t2.q1 = ss1.q2 inner join + (select coalesce(q1, 0) as x, * from int8_tbl t3) ss1 on t2.q1 = ss1.q2 inner join lateral (select ss1.x as y, * from int8_tbl t4) ss2 on t2.q2 = ss2.q1) on t1.q2 = ss2.q1 order by 1, 2, 3; @@ -1059,7 +1059,7 @@ explain (verbose, costs off) select ss2.* from int8_tbl t1 left join (int8_tbl t2 left join - (select coalesce(q1) as x, * from int8_tbl t3) ss1 on t2.q1 = ss1.q2 left join + (select coalesce(q1, 0) as x, * from int8_tbl t3) ss1 on t2.q1 = ss1.q2 left join lateral (select ss1.x as y, * from int8_tbl t4) ss2 on t2.q2 = ss2.q1) on t1.q2 = ss2.q1 order by 1, 2, 3; @@ -1067,7 +1067,7 @@ order by 1, 2, 3; select ss2.* from int8_tbl t1 left join (int8_tbl t2 left join - (select coalesce(q1) as x, * from int8_tbl t3) ss1 on t2.q1 = ss1.q2 left join + (select coalesce(q1, 0) as x, * from int8_tbl t3) ss1 on t2.q1 = ss1.q2 left join lateral (select ss1.x as y, * from int8_tbl t4) ss2 on t2.q2 = ss2.q1) on t1.q2 = ss2.q1 order by 1, 2, 3;