-- -- SUBSELECT -- SELECT 1 AS one WHERE 1 IN (SELECT 1); one ----- 1 (1 row) SELECT 1 AS zero WHERE 1 NOT IN (SELECT 1); zero ------ (0 rows) SELECT 1 AS zero WHERE 1 IN (SELECT 2); zero ------ (0 rows) -- Check grammar's handling of extra parens in assorted contexts SELECT * FROM (SELECT 1 AS x) ss; x --- 1 (1 row) SELECT * FROM ((SELECT 1 AS x)) ss; x --- 1 (1 row) (SELECT 2) UNION SELECT 2; ?column? ---------- 2 (1 row) ((SELECT 2)) UNION SELECT 2; ?column? ---------- 2 (1 row) SELECT ((SELECT 2) UNION SELECT 2); ?column? ---------- 2 (1 row) SELECT (((SELECT 2)) UNION SELECT 2); ?column? ---------- 2 (1 row) SELECT (SELECT ARRAY[1,2,3])[1]; array ------- 1 (1 row) SELECT ((SELECT ARRAY[1,2,3]))[2]; array ------- 2 (1 row) SELECT (((SELECT ARRAY[1,2,3])))[3]; array ------- 3 (1 row) -- Set up some simple test tables CREATE TABLE SUBSELECT_TBL ( f1 integer, f2 integer, f3 float ); INSERT INTO SUBSELECT_TBL VALUES (1, 2, 3); INSERT INTO SUBSELECT_TBL VALUES (2, 3, 4); INSERT INTO SUBSELECT_TBL VALUES (3, 4, 5); INSERT INTO SUBSELECT_TBL VALUES (1, 1, 1); INSERT INTO SUBSELECT_TBL VALUES (2, 2, 2); INSERT INTO SUBSELECT_TBL VALUES (3, 3, 3); INSERT INTO SUBSELECT_TBL VALUES (6, 7, 8); INSERT INTO SUBSELECT_TBL VALUES (8, 9, NULL); SELECT '' AS eight, * FROM SUBSELECT_TBL; eight | f1 | f2 | f3 -------+----+----+---- | 1 | 2 | 3 | 2 | 3 | 4 | 3 | 4 | 5 | 1 | 1 | 1 | 2 | 2 | 2 | 3 | 3 | 3 | 6 | 7 | 8 | 8 | 9 | (8 rows) -- Uncorrelated subselects SELECT '' AS two, f1 AS "Constant Select" FROM SUBSELECT_TBL WHERE f1 IN (SELECT 1); two | Constant Select -----+----------------- | 1 | 1 (2 rows) SELECT '' AS six, f1 AS "Uncorrelated Field" FROM SUBSELECT_TBL WHERE f1 IN (SELECT f2 FROM SUBSELECT_TBL); six | Uncorrelated Field -----+-------------------- | 1 | 2 | 3 | 1 | 2 | 3 (6 rows) SELECT '' AS six, f1 AS "Uncorrelated Field" FROM SUBSELECT_TBL WHERE f1 IN (SELECT f2 FROM SUBSELECT_TBL WHERE f2 IN (SELECT f1 FROM SUBSELECT_TBL)); six | Uncorrelated Field -----+-------------------- | 1 | 2 | 3 | 1 | 2 | 3 (6 rows) SELECT '' AS three, f1, f2 FROM SUBSELECT_TBL WHERE (f1, f2) NOT IN (SELECT f2, CAST(f3 AS int4) FROM SUBSELECT_TBL WHERE f3 IS NOT NULL); three | f1 | f2 -------+----+---- | 1 | 2 | 6 | 7 | 8 | 9 (3 rows) -- Correlated subselects SELECT '' AS six, f1 AS "Correlated Field", f2 AS "Second Field" FROM SUBSELECT_TBL upper WHERE f1 IN (SELECT f2 FROM SUBSELECT_TBL WHERE f1 = upper.f1); six | Correlated Field | Second Field -----+------------------+-------------- | 1 | 2 | 2 | 3 | 3 | 4 | 1 | 1 | 2 | 2 | 3 | 3 (6 rows) SELECT '' AS six, f1 AS "Correlated Field", f3 AS "Second Field" FROM SUBSELECT_TBL upper WHERE f1 IN (SELECT f2 FROM SUBSELECT_TBL WHERE CAST(upper.f2 AS float) = f3); six | Correlated Field | Second Field -----+------------------+-------------- | 2 | 4 | 3 | 5 | 1 | 1 | 2 | 2 | 3 | 3 (5 rows) SELECT '' AS six, f1 AS "Correlated Field", f3 AS "Second Field" FROM SUBSELECT_TBL upper WHERE f3 IN (SELECT upper.f1 + f2 FROM SUBSELECT_TBL WHERE f2 = CAST(f3 AS integer)); six | Correlated Field | Second Field -----+------------------+-------------- | 1 | 3 | 2 | 4 | 3 | 5 | 6 | 8 (4 rows) SELECT '' AS five, f1 AS "Correlated Field" FROM SUBSELECT_TBL WHERE (f1, f2) IN (SELECT f2, CAST(f3 AS int4) FROM SUBSELECT_TBL WHERE f3 IS NOT NULL); five | Correlated Field ------+------------------ | 2 | 3 | 1 | 2 | 3 (5 rows) -- -- Use some existing tables in the regression test -- SELECT '' AS eight, ss.f1 AS "Correlated Field", ss.f3 AS "Second Field" FROM SUBSELECT_TBL ss WHERE f1 NOT IN (SELECT f1+1 FROM INT4_TBL WHERE f1 != ss.f1 AND f1 < 2147483647); eight | Correlated Field | Second Field -------+------------------+-------------- | 2 | 4 | 3 | 5 | 2 | 2 | 3 | 3 | 6 | 8 | 8 | (6 rows) select q1, float8(count(*)) / (select count(*) from int8_tbl) from int8_tbl group by q1 order by q1; q1 | ?column? ------------------+---------- 123 | 0.4 4567890123456789 | 0.6 (2 rows) -- Unspecified-type literals in output columns should resolve as text SELECT *, pg_typeof(f1) FROM (SELECT 'foo' AS f1 FROM generate_series(1,3)) ss ORDER BY 1; f1 | pg_typeof -----+----------- foo | text foo | text foo | text (3 rows) -- ... unless there's context to suggest differently explain (verbose, costs off) select '42' union all select '43'; QUERY PLAN ---------------------------- Append -> Result Output: '42'::text -> Result Output: '43'::text (5 rows) explain (verbose, costs off) select '42' union all select 43; QUERY PLAN -------------------- Append -> Result Output: 42 -> Result Output: 43 (5 rows) -- check materialization of an initplan reference (bug #14524) explain (verbose, costs off) select 1 = all (select (select 1)); QUERY PLAN ----------------------------------- Result Output: (SubPlan 2) SubPlan 2 -> Materialize Output: ($0) InitPlan 1 (returns $0) -> Result Output: 1 -> Result Output: $0 (10 rows) select 1 = all (select (select 1)); ?column? ---------- t (1 row) -- -- Check EXISTS simplification with LIMIT -- explain (costs off) select * from int4_tbl o where exists (select 1 from int4_tbl i where i.f1=o.f1 limit null); QUERY PLAN ------------------------------------ Hash Semi Join Hash Cond: (o.f1 = i.f1) -> Seq Scan on int4_tbl o -> Hash -> Seq Scan on int4_tbl i (5 rows) explain (costs off) select * from int4_tbl o where not exists (select 1 from int4_tbl i where i.f1=o.f1 limit 1); QUERY PLAN ------------------------------------ Hash Anti Join Hash Cond: (o.f1 = i.f1) -> Seq Scan on int4_tbl o -> Hash -> Seq Scan on int4_tbl i (5 rows) explain (costs off) select * from int4_tbl o where exists (select 1 from int4_tbl i where i.f1=o.f1 limit 0); QUERY PLAN -------------------------------------- Seq Scan on int4_tbl o Filter: (SubPlan 1) SubPlan 1 -> Limit -> Seq Scan on int4_tbl i Filter: (f1 = o.f1) (6 rows) -- -- Test cases to catch unpleasant interactions between IN-join processing -- and subquery pullup. -- select count(*) from (select 1 from tenk1 a where unique1 IN (select hundred from tenk1 b)) ss; count ------- 100 (1 row) select count(distinct ss.ten) from (select ten from tenk1 a where unique1 IN (select hundred from tenk1 b)) ss; count ------- 10 (1 row) select count(*) from (select 1 from tenk1 a where unique1 IN (select distinct hundred from tenk1 b)) ss; count ------- 100 (1 row) select count(distinct ss.ten) from (select ten from tenk1 a where unique1 IN (select distinct hundred from tenk1 b)) ss; count ------- 10 (1 row) -- -- Test cases to check for overenthusiastic optimization of -- "IN (SELECT DISTINCT ...)" and related cases. Per example from -- Luca Pireddu and Michael Fuhr. -- CREATE TEMP TABLE foo (id integer); CREATE TEMP TABLE bar (id1 integer, id2 integer); INSERT INTO foo VALUES (1); INSERT INTO bar VALUES (1, 1); INSERT INTO bar VALUES (2, 2); INSERT INTO bar VALUES (3, 1); -- These cases require an extra level of distinct-ing above subquery s SELECT * FROM foo WHERE id IN (SELECT id2 FROM (SELECT DISTINCT id1, id2 FROM bar) AS s); id ---- 1 (1 row) SELECT * FROM foo WHERE id IN (SELECT id2 FROM (SELECT id1,id2 FROM bar GROUP BY id1,id2) AS s); id ---- 1 (1 row) SELECT * FROM foo WHERE id IN (SELECT id2 FROM (SELECT id1, id2 FROM bar UNION SELECT id1, id2 FROM bar) AS s); id ---- 1 (1 row) -- These cases do not SELECT * FROM foo WHERE id IN (SELECT id2 FROM (SELECT DISTINCT ON (id2) id1, id2 FROM bar) AS s); id ---- 1 (1 row) SELECT * FROM foo WHERE id IN (SELECT id2 FROM (SELECT id2 FROM bar GROUP BY id2) AS s); id ---- 1 (1 row) SELECT * FROM foo WHERE id IN (SELECT id2 FROM (SELECT id2 FROM bar UNION SELECT id2 FROM bar) AS s); id ---- 1 (1 row) -- -- Test case to catch problems with multiply nested sub-SELECTs not getting -- recalculated properly. Per bug report from Didier Moens. -- CREATE TABLE orderstest ( approver_ref integer, po_ref integer, ordercanceled boolean ); INSERT INTO orderstest VALUES (1, 1, false); INSERT INTO orderstest VALUES (66, 5, false); INSERT INTO orderstest VALUES (66, 6, false); INSERT INTO orderstest VALUES (66, 7, false); INSERT INTO orderstest VALUES (66, 1, true); INSERT INTO orderstest VALUES (66, 8, false); INSERT INTO orderstest VALUES (66, 1, false); INSERT INTO orderstest VALUES (77, 1, false); INSERT INTO orderstest VALUES (1, 1, false); INSERT INTO orderstest VALUES (66, 1, false); INSERT INTO orderstest VALUES (1, 1, false); CREATE VIEW orders_view AS SELECT *, (SELECT CASE WHEN ord.approver_ref=1 THEN '---' ELSE 'Approved' END) AS "Approved", (SELECT CASE WHEN ord.ordercanceled THEN 'Canceled' ELSE (SELECT CASE WHEN ord.po_ref=1 THEN (SELECT CASE WHEN ord.approver_ref=1 THEN '---' ELSE 'Approved' END) ELSE 'PO' END) END) AS "Status", (CASE WHEN ord.ordercanceled THEN 'Canceled' ELSE (CASE WHEN ord.po_ref=1 THEN (CASE WHEN ord.approver_ref=1 THEN '---' ELSE 'Approved' END) ELSE 'PO' END) END) AS "Status_OK" FROM orderstest ord; SELECT * FROM orders_view; approver_ref | po_ref | ordercanceled | Approved | Status | Status_OK --------------+--------+---------------+----------+----------+----------- 1 | 1 | f | --- | --- | --- 66 | 5 | f | Approved | PO | PO 66 | 6 | f | Approved | PO | PO 66 | 7 | f | Approved | PO | PO 66 | 1 | t | Approved | Canceled | Canceled 66 | 8 | f | Approved | PO | PO 66 | 1 | f | Approved | Approved | Approved 77 | 1 | f | Approved | Approved | Approved 1 | 1 | f | --- | --- | --- 66 | 1 | f | Approved | Approved | Approved 1 | 1 | f | --- | --- | --- (11 rows) DROP TABLE orderstest cascade; NOTICE: drop cascades to view orders_view -- -- Test cases to catch situations where rule rewriter fails to propagate -- hasSubLinks flag correctly. Per example from Kyle Bateman. -- create temp table parts ( partnum text, cost float8 ); create temp table shipped ( ttype char(2), ordnum int4, partnum text, value float8 ); create temp view shipped_view as select * from shipped where ttype = 'wt'; create rule shipped_view_insert as on insert to shipped_view do instead insert into shipped values('wt', new.ordnum, new.partnum, new.value); insert into parts (partnum, cost) values (1, 1234.56); insert into shipped_view (ordnum, partnum, value) values (0, 1, (select cost from parts where partnum = '1')); select * from shipped_view; ttype | ordnum | partnum | value -------+--------+---------+--------- wt | 0 | 1 | 1234.56 (1 row) create rule shipped_view_update as on update to shipped_view do instead update shipped set partnum = new.partnum, value = new.value where ttype = new.ttype and ordnum = new.ordnum; update shipped_view set value = 11 from int4_tbl a join int4_tbl b on (a.f1 = (select f1 from int4_tbl c where c.f1=b.f1)) where ordnum = a.f1; select * from shipped_view; ttype | ordnum | partnum | value -------+--------+---------+------- wt | 0 | 1 | 11 (1 row) select f1, ss1 as relabel from (select *, (select sum(f1) from int4_tbl b where f1 >= a.f1) as ss1 from int4_tbl a) ss; f1 | relabel -------------+------------ 0 | 2147607103 123456 | 2147607103 -123456 | 2147483647 2147483647 | 2147483647 -2147483647 | 0 (5 rows) -- -- Test cases involving PARAM_EXEC parameters and min/max index optimizations. -- Per bug report from David Sanchez i Gregori. -- select * from ( select max(unique1) from tenk1 as a where exists (select 1 from tenk1 as b where b.thousand = a.unique2) ) ss; max ------ 9997 (1 row) select * from ( select min(unique1) from tenk1 as a where not exists (select 1 from tenk1 as b where b.unique2 = 10000) ) ss; min ----- 0 (1 row) -- -- Test that an IN implemented using a UniquePath does unique-ification -- with the right semantics, as per bug #4113. (Unfortunately we have -- no simple way to ensure that this test case actually chooses that type -- of plan, but it does in releases 7.4-8.3. Note that an ordering difference -- here might mean that some other plan type is being used, rendering the test -- pointless.) -- create temp table numeric_table (num_col numeric); insert into numeric_table values (1), (1.000000000000000000001), (2), (3); create temp table float_table (float_col float8); insert into float_table values (1), (2), (3); select * from float_table where float_col in (select num_col from numeric_table); float_col ----------- 1 2 3 (3 rows) select * from numeric_table where num_col in (select float_col from float_table); num_col ------------------------- 1 1.000000000000000000001 2 3 (4 rows) -- -- Test case for bug #4290: bogus calculation of subplan param sets -- create temp table ta (id int primary key, val int); insert into ta values(1,1); insert into ta values(2,2); create temp table tb (id int primary key, aval int); insert into tb values(1,1); insert into tb values(2,1); insert into tb values(3,2); insert into tb values(4,2); create temp table tc (id int primary key, aid int); insert into tc values(1,1); insert into tc values(2,2); select ( select min(tb.id) from tb where tb.aval = (select ta.val from ta where ta.id = tc.aid) ) as min_tb_id from tc; min_tb_id ----------- 1 3 (2 rows) -- -- Test case for 8.3 "failed to locate grouping columns" bug -- create temp table t1 (f1 numeric(14,0), f2 varchar(30)); select * from (select distinct f1, f2, (select f2 from t1 x where x.f1 = up.f1) as fs from t1 up) ss group by f1,f2,fs; f1 | f2 | fs ----+----+---- (0 rows) -- -- Test case for bug #5514 (mishandling of whole-row Vars in subselects) -- create temp table table_a(id integer); insert into table_a values (42); create temp view view_a as select * from table_a; select view_a from view_a; view_a -------- (42) (1 row) select (select view_a) from view_a; view_a -------- (42) (1 row) select (select (select view_a)) from view_a; view_a -------- (42) (1 row) select (select (a.*)::text) from view_a a; a ------ (42) (1 row) -- -- Check that whole-row Vars reading the result of a subselect don't include -- any junk columns therein -- select q from (select max(f1) from int4_tbl group by f1 order by f1) q; q --------------- (-2147483647) (-123456) (0) (123456) (2147483647) (5 rows) with q as (select max(f1) from int4_tbl group by f1 order by f1) select q from q; q --------------- (-2147483647) (-123456) (0) (123456) (2147483647) (5 rows) -- -- Test case for sublinks pulled up into joinaliasvars lists in an -- inherited update/delete query -- begin; -- this shouldn't delete anything, but be safe delete from road where exists ( select 1 from int4_tbl cross join ( select f1, array(select q1 from int8_tbl) as arr from text_tbl ) ss where road.name = ss.f1 ); rollback; -- -- Test case for sublinks pushed down into subselects via join alias expansion -- select (select sq1) as qq1 from (select exists(select 1 from int4_tbl where f1 = q2) as sq1, 42 as dummy from int8_tbl) sq0 join int4_tbl i4 on dummy = i4.f1; qq1 ----- (0 rows) -- -- Test case for subselect within UPDATE of INSERT...ON CONFLICT DO UPDATE -- create temp table upsert(key int4 primary key, val text); insert into upsert values(1, 'val') on conflict (key) do update set val = 'not seen'; insert into upsert values(1, 'val') on conflict (key) do update set val = 'seen with subselect ' || (select f1 from int4_tbl where f1 != 0 limit 1)::text; select * from upsert; key | val -----+---------------------------- 1 | seen with subselect 123456 (1 row) with aa as (select 'int4_tbl' u from int4_tbl limit 1) insert into upsert values (1, 'x'), (999, 'y') on conflict (key) do update set val = (select u from aa) returning *; key | val -----+---------- 1 | int4_tbl 999 | y (2 rows) -- -- Test case for cross-type partial matching in hashed subplan (bug #7597) -- create temp table outer_7597 (f1 int4, f2 int4); insert into outer_7597 values (0, 0); insert into outer_7597 values (1, 0); insert into outer_7597 values (0, null); insert into outer_7597 values (1, null); create temp table inner_7597(c1 int8, c2 int8); insert into inner_7597 values(0, null); select * from outer_7597 where (f1, f2) not in (select * from inner_7597); f1 | f2 ----+---- 1 | 0 1 | (2 rows) -- -- Similar test case using text that verifies that collation -- information is passed through by execTuplesEqual() in nodeSubplan.c -- (otherwise it would error in texteq()) -- create temp table outer_text (f1 text, f2 text); insert into outer_text values ('a', 'a'); insert into outer_text values ('b', 'a'); insert into outer_text values ('a', null); insert into outer_text values ('b', null); create temp table inner_text (c1 text, c2 text); insert into inner_text values ('a', null); select * from outer_text where (f1, f2) not in (select * from inner_text); f1 | f2 ----+---- b | a b | (2 rows) -- -- Test case for premature memory release during hashing of subplan output -- select '1'::text in (select '1'::name union all select '1'::name); ?column? ---------- t (1 row) -- -- Test case for planner bug with nested EXISTS handling -- select a.thousand from tenk1 a, tenk1 b where a.thousand = b.thousand and exists ( select 1 from tenk1 c where b.hundred = c.hundred and not exists ( select 1 from tenk1 d where a.thousand = d.thousand ) ); thousand ---------- (0 rows) -- -- Check that nested sub-selects are not pulled up if they contain volatiles -- explain (verbose, costs off) select x, x from (select (select now()) as x from (values(1),(2)) v(y)) ss; QUERY PLAN --------------------------- Values Scan on "*VALUES*" Output: $0, $1 InitPlan 1 (returns $0) -> Result Output: now() InitPlan 2 (returns $1) -> Result Output: now() (8 rows) explain (verbose, costs off) select x, x from (select (select random()) as x from (values(1),(2)) v(y)) ss; QUERY PLAN ---------------------------------- Subquery Scan on ss Output: ss.x, ss.x -> Values Scan on "*VALUES*" Output: $0 InitPlan 1 (returns $0) -> Result Output: random() (7 rows) explain (verbose, costs off) select x, x from (select (select now() where y=y) as x from (values(1),(2)) v(y)) ss; QUERY PLAN ---------------------------------------------------------------------- Values Scan on "*VALUES*" Output: (SubPlan 1), (SubPlan 2) SubPlan 1 -> Result Output: now() One-Time Filter: ("*VALUES*".column1 = "*VALUES*".column1) SubPlan 2 -> Result Output: now() One-Time Filter: ("*VALUES*".column1 = "*VALUES*".column1) (10 rows) explain (verbose, costs off) select x, x from (select (select random() where y=y) as x from (values(1),(2)) v(y)) ss; QUERY PLAN ---------------------------------------------------------------------------- Subquery Scan on ss Output: ss.x, ss.x -> Values Scan on "*VALUES*" Output: (SubPlan 1) SubPlan 1 -> Result Output: random() One-Time Filter: ("*VALUES*".column1 = "*VALUES*".column1) (8 rows) -- -- Check we don't misoptimize a NOT IN where the subquery returns no rows. -- create temp table notinouter (a int); create temp table notininner (b int not null); insert into notinouter values (null), (1); select * from notinouter where a not in (select b from notininner); a --- 1 (2 rows) -- -- Check we behave sanely in corner case of empty SELECT list (bug #8648) -- create temp table nocolumns(); select exists(select * from nocolumns); exists -------- f (1 row) -- -- Check behavior with a SubPlan in VALUES (bug #14924) -- select val.x from generate_series(1,10) as s(i), lateral ( values ((select s.i + 1)), (s.i + 101) ) as val(x) where s.i < 10 and (select val.x) < 110; x ----- 2 102 3 103 4 104 5 105 6 106 7 107 8 108 9 109 10 (17 rows) -- -- Check sane behavior with nested IN SubLinks -- explain (verbose, costs off) select * from int4_tbl where (case when f1 in (select unique1 from tenk1 a) then f1 else null end) in (select ten from tenk1 b); QUERY PLAN --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- Nested Loop Semi Join Output: int4_tbl.f1 Join Filter: (CASE WHEN (hashed SubPlan 1) THEN int4_tbl.f1 ELSE NULL::integer END = b.ten) -> Seq Scan on public.int4_tbl Output: int4_tbl.f1 -> Seq Scan on public.tenk1 b Output: b.unique1, b.unique2, b.two, b.four, b.ten, b.twenty, b.hundred, b.thousand, b.twothousand, b.fivethous, b.tenthous, b.odd, b.even, b.stringu1, b.stringu2, b.string4 SubPlan 1 -> Index Only Scan using tenk1_unique1 on public.tenk1 a Output: a.unique1 (10 rows) select * from int4_tbl where (case when f1 in (select unique1 from tenk1 a) then f1 else null end) in (select ten from tenk1 b); f1 ---- 0 (1 row) -- -- Check for incorrect optimization when IN subquery contains a SRF -- explain (verbose, costs off) select * from int4_tbl o where (f1, f1) in (select f1, generate_series(1,50) / 10 g from int4_tbl i group by f1); QUERY PLAN ------------------------------------------------------------------- Nested Loop Semi Join Output: o.f1 Join Filter: (o.f1 = "ANY_subquery".f1) -> Seq Scan on public.int4_tbl o Output: o.f1 -> Materialize Output: "ANY_subquery".f1, "ANY_subquery".g -> Subquery Scan on "ANY_subquery" Output: "ANY_subquery".f1, "ANY_subquery".g Filter: ("ANY_subquery".f1 = "ANY_subquery".g) -> Result Output: i.f1, ((generate_series(1, 50)) / 10) -> ProjectSet Output: generate_series(1, 50), i.f1 -> HashAggregate Output: i.f1 Group Key: i.f1 -> Seq Scan on public.int4_tbl i Output: i.f1 (19 rows) select * from int4_tbl o where (f1, f1) in (select f1, generate_series(1,50) / 10 g from int4_tbl i group by f1); f1 ---- 0 (1 row) -- -- check for over-optimization of whole-row Var referencing an Append plan -- select (select q from (select 1,2,3 where f1 > 0 union all select 4,5,6.0 where f1 <= 0 ) q ) from int4_tbl; q ----------- (4,5,6.0) (1,2,3) (4,5,6.0) (1,2,3) (4,5,6.0) (5 rows) -- -- Check that volatile quals aren't pushed down past a DISTINCT: -- nextval() should not be called more than the nominal number of times -- create temp sequence ts1; select * from (select distinct ten from tenk1) ss where ten < 10 + nextval('ts1') order by 1; ten ----- 0 1 2 3 4 5 6 7 8 9 (10 rows) select nextval('ts1'); nextval --------- 11 (1 row) -- -- Check that volatile quals aren't pushed down past a set-returning function; -- while a nonvolatile qual can be, if it doesn't reference the SRF. -- create function tattle(x int, y int) returns bool volatile language plpgsql as $$ begin raise notice 'x = %, y = %', x, y; return x > y; end$$; explain (verbose, costs off) select * from (select 9 as x, unnest(array[1,2,3,11,12,13]) as u) ss where tattle(x, 8); QUERY PLAN ---------------------------------------------------------- Subquery Scan on ss Output: ss.x, ss.u Filter: tattle(ss.x, 8) -> ProjectSet Output: 9, unnest('{1,2,3,11,12,13}'::integer[]) -> Result (6 rows) select * from (select 9 as x, unnest(array[1,2,3,11,12,13]) as u) ss where tattle(x, 8); NOTICE: x = 9, y = 8 NOTICE: x = 9, y = 8 NOTICE: x = 9, y = 8 NOTICE: x = 9, y = 8 NOTICE: x = 9, y = 8 NOTICE: x = 9, y = 8 x | u ---+---- 9 | 1 9 | 2 9 | 3 9 | 11 9 | 12 9 | 13 (6 rows) -- if we pretend it's stable, we get different results: alter function tattle(x int, y int) stable; explain (verbose, costs off) select * from (select 9 as x, unnest(array[1,2,3,11,12,13]) as u) ss where tattle(x, 8); QUERY PLAN ---------------------------------------------------- ProjectSet Output: 9, unnest('{1,2,3,11,12,13}'::integer[]) -> Result One-Time Filter: tattle(9, 8) (4 rows) select * from (select 9 as x, unnest(array[1,2,3,11,12,13]) as u) ss where tattle(x, 8); NOTICE: x = 9, y = 8 x | u ---+---- 9 | 1 9 | 2 9 | 3 9 | 11 9 | 12 9 | 13 (6 rows) -- although even a stable qual should not be pushed down if it references SRF explain (verbose, costs off) select * from (select 9 as x, unnest(array[1,2,3,11,12,13]) as u) ss where tattle(x, u); QUERY PLAN ---------------------------------------------------------- Subquery Scan on ss Output: ss.x, ss.u Filter: tattle(ss.x, ss.u) -> ProjectSet Output: 9, unnest('{1,2,3,11,12,13}'::integer[]) -> Result (6 rows) select * from (select 9 as x, unnest(array[1,2,3,11,12,13]) as u) ss where tattle(x, u); NOTICE: x = 9, y = 1 NOTICE: x = 9, y = 2 NOTICE: x = 9, y = 3 NOTICE: x = 9, y = 11 NOTICE: x = 9, y = 12 NOTICE: x = 9, y = 13 x | u ---+--- 9 | 1 9 | 2 9 | 3 (3 rows) drop function tattle(x int, y int); -- -- Test that LIMIT can be pushed to SORT through a subquery that just projects -- columns. We check for that having happened by looking to see if EXPLAIN -- ANALYZE shows that a top-N sort was used. We must suppress or filter away -- all the non-invariant parts of the EXPLAIN ANALYZE output. -- create table sq_limit (pk int primary key, c1 int, c2 int); insert into sq_limit values (1, 1, 1), (2, 2, 2), (3, 3, 3), (4, 4, 4), (5, 1, 1), (6, 2, 2), (7, 3, 3), (8, 4, 4); create function explain_sq_limit() returns setof text language plpgsql as $$ declare ln text; begin for ln in explain (analyze, summary off, timing off, costs off) select * from (select pk,c2 from sq_limit order by c1,pk) as x limit 3 loop ln := regexp_replace(ln, 'Memory: \S*', 'Memory: xxx'); -- this case might occur if force_parallel_mode is on: ln := regexp_replace(ln, 'Worker 0: Sort Method', 'Sort Method'); return next ln; end loop; end; $$; select * from explain_sq_limit(); explain_sq_limit ---------------------------------------------------------------- Limit (actual rows=3 loops=1) -> Subquery Scan on x (actual rows=3 loops=1) -> Sort (actual rows=3 loops=1) Sort Key: sq_limit.c1, sq_limit.pk Sort Method: top-N heapsort Memory: xxx -> Seq Scan on sq_limit (actual rows=8 loops=1) (6 rows) select * from (select pk,c2 from sq_limit order by c1,pk) as x limit 3; pk | c2 ----+---- 1 | 1 5 | 1 2 | 2 (3 rows) drop function explain_sq_limit(); drop table sq_limit; -- -- Ensure that backward scan direction isn't propagated into -- expression subqueries (bug #15336) -- begin; declare c1 scroll cursor for select * from generate_series(1,4) i where i <> all (values (2),(3)); move forward all in c1; fetch backward all in c1; i --- 4 1 (2 rows) commit; -- -- Tests for CTE inlining behavior -- -- Basic subquery that can be inlined explain (verbose, costs off) with x as (select * from (select f1 from subselect_tbl) ss) select * from x where f1 = 1; QUERY PLAN ---------------------------------- Seq Scan on public.subselect_tbl Output: subselect_tbl.f1 Filter: (subselect_tbl.f1 = 1) (3 rows) -- Explicitly request materialization explain (verbose, costs off) with x as materialized (select * from (select f1 from subselect_tbl) ss) select * from x where f1 = 1; QUERY PLAN ------------------------------------------ CTE Scan on x Output: x.f1 Filter: (x.f1 = 1) CTE x -> Seq Scan on public.subselect_tbl Output: subselect_tbl.f1 (6 rows) -- Stable functions are safe to inline explain (verbose, costs off) with x as (select * from (select f1, now() from subselect_tbl) ss) select * from x where f1 = 1; QUERY PLAN ----------------------------------- Seq Scan on public.subselect_tbl Output: subselect_tbl.f1, now() Filter: (subselect_tbl.f1 = 1) (3 rows) -- Volatile functions prevent inlining explain (verbose, costs off) with x as (select * from (select f1, random() from subselect_tbl) ss) select * from x where f1 = 1; QUERY PLAN ---------------------------------------------- CTE Scan on x Output: x.f1, x.random Filter: (x.f1 = 1) CTE x -> Seq Scan on public.subselect_tbl Output: subselect_tbl.f1, random() (6 rows) -- SELECT FOR UPDATE cannot be inlined explain (verbose, costs off) with x as (select * from (select f1 from subselect_tbl for update) ss) select * from x where f1 = 1; QUERY PLAN -------------------------------------------------------------------- CTE Scan on x Output: x.f1 Filter: (x.f1 = 1) CTE x -> Subquery Scan on ss Output: ss.f1 -> LockRows Output: subselect_tbl.f1, subselect_tbl.ctid -> Seq Scan on public.subselect_tbl Output: subselect_tbl.f1, subselect_tbl.ctid (10 rows) -- Multiply-referenced CTEs are inlined only when requested explain (verbose, costs off) with x as (select * from (select f1, now() as n from subselect_tbl) ss) select * from x, x x2 where x.n = x2.n; QUERY PLAN ------------------------------------------- Merge Join Output: x.f1, x.n, x2.f1, x2.n Merge Cond: (x.n = x2.n) CTE x -> Seq Scan on public.subselect_tbl Output: subselect_tbl.f1, now() -> Sort Output: x.f1, x.n Sort Key: x.n -> CTE Scan on x Output: x.f1, x.n -> Sort Output: x2.f1, x2.n Sort Key: x2.n -> CTE Scan on x x2 Output: x2.f1, x2.n (16 rows) explain (verbose, costs off) with x as not materialized (select * from (select f1, now() as n from subselect_tbl) ss) select * from x, x x2 where x.n = x2.n; QUERY PLAN ---------------------------------------------------------------------------- Result Output: subselect_tbl.f1, now(), subselect_tbl_1.f1, now() One-Time Filter: (now() = now()) -> Nested Loop Output: subselect_tbl.f1, subselect_tbl_1.f1 -> Seq Scan on public.subselect_tbl Output: subselect_tbl.f1, subselect_tbl.f2, subselect_tbl.f3 -> Materialize Output: subselect_tbl_1.f1 -> Seq Scan on public.subselect_tbl subselect_tbl_1 Output: subselect_tbl_1.f1 (11 rows) -- Multiply-referenced CTEs can't be inlined if they contain outer self-refs explain (verbose, costs off) with recursive x(a) as ((values ('a'), ('b')) union all (with z as not materialized (select * from x) select z.a || z1.a as a from z cross join z as z1 where length(z.a || z1.a) < 5)) select * from x; QUERY PLAN ---------------------------------------------------------- CTE Scan on x Output: x.a CTE x -> Recursive Union -> Values Scan on "*VALUES*" Output: "*VALUES*".column1 -> Nested Loop Output: (z.a || z1.a) Join Filter: (length((z.a || z1.a)) < 5) CTE z -> WorkTable Scan on x x_1 Output: x_1.a -> CTE Scan on z Output: z.a -> CTE Scan on z z1 Output: z1.a (16 rows) with recursive x(a) as ((values ('a'), ('b')) union all (with z as not materialized (select * from x) select z.a || z1.a as a from z cross join z as z1 where length(z.a || z1.a) < 5)) select * from x; a ------ a b aa ab ba bb aaaa aaab aaba aabb abaa abab abba abbb baaa baab baba babb bbaa bbab bbba bbbb (22 rows) explain (verbose, costs off) with recursive x(a) as ((values ('a'), ('b')) union all (with z as not materialized (select * from x) select z.a || z.a as a from z where length(z.a || z.a) < 5)) select * from x; QUERY PLAN -------------------------------------------------------- CTE Scan on x Output: x.a CTE x -> Recursive Union -> Values Scan on "*VALUES*" Output: "*VALUES*".column1 -> WorkTable Scan on x x_1 Output: (x_1.a || x_1.a) Filter: (length((x_1.a || x_1.a)) < 5) (9 rows) with recursive x(a) as ((values ('a'), ('b')) union all (with z as not materialized (select * from x) select z.a || z.a as a from z where length(z.a || z.a) < 5)) select * from x; a ------ a b aa bb aaaa bbbb (6 rows) -- Check handling of outer references explain (verbose, costs off) with x as (select * from int4_tbl) select * from (with y as (select * from x) select * from y) ss; QUERY PLAN ----------------------------- Seq Scan on public.int4_tbl Output: int4_tbl.f1 (2 rows) explain (verbose, costs off) with x as materialized (select * from int4_tbl) select * from (with y as (select * from x) select * from y) ss; QUERY PLAN ------------------------------------- CTE Scan on x Output: x.f1 CTE x -> Seq Scan on public.int4_tbl Output: int4_tbl.f1 (5 rows) -- Ensure that we inline the currect CTE when there are -- multiple CTEs with the same name explain (verbose, costs off) with x as (select 1 as y) select * from (with x as (select 2 as y) select * from x) ss; QUERY PLAN ------------- Result Output: 2 (2 rows) -- Row marks are not pushed into CTEs explain (verbose, costs off) with x as (select * from subselect_tbl) select * from x for update; QUERY PLAN ---------------------------------------------------------------- Seq Scan on public.subselect_tbl Output: subselect_tbl.f1, subselect_tbl.f2, subselect_tbl.f3 (2 rows)