postgresql/src/test/regress/expected/union.out

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--
-- UNION (also INTERSECT, EXCEPT)
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--
-- Simple UNION constructs
SELECT 1 AS two UNION SELECT 2;
two
-----
1
2
(2 rows)
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SELECT 1 AS one UNION SELECT 1;
one
-----
1
(1 row)
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SELECT 1 AS two UNION ALL SELECT 2;
two
-----
1
2
(2 rows)
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SELECT 1 AS two UNION ALL SELECT 1;
two
-----
1
1
(2 rows)
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SELECT 1 AS three UNION SELECT 2 UNION SELECT 3;
three
-------
1
2
3
(3 rows)
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SELECT 1 AS two UNION SELECT 2 UNION SELECT 2;
two
-----
1
2
(2 rows)
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SELECT 1 AS three UNION SELECT 2 UNION ALL SELECT 2;
three
-------
1
2
2
(3 rows)
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SELECT 1.1 AS two UNION SELECT 2.2;
two
-----
1.1
2.2
(2 rows)
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-- Mixed types
SELECT 1.1 AS two UNION SELECT 2;
two
-----
1.1
2
(2 rows)
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SELECT 1 AS two UNION SELECT 2.2;
two
-----
1
2.2
(2 rows)
SELECT 1 AS one UNION SELECT 1.0::float8;
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one
-----
1
(1 row)
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SELECT 1.1 AS two UNION ALL SELECT 2;
two
-----
1.1
2
(2 rows)
SELECT 1.0::float8 AS two UNION ALL SELECT 1;
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two
-----
1
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1
(2 rows)
SELECT 1.1 AS three UNION SELECT 2 UNION SELECT 3;
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three
-------
1.1
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2
3
(3 rows)
SELECT 1.1::float8 AS two UNION SELECT 2 UNION SELECT 2.0::float8 ORDER BY 1;
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two
-----
1.1
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2
(2 rows)
SELECT 1.1 AS three UNION SELECT 2 UNION ALL SELECT 2;
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three
-------
1.1
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2
2
(3 rows)
SELECT 1.1 AS two UNION (SELECT 2 UNION ALL SELECT 2);
two
-----
1.1
2
(2 rows)
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--
-- Try testing from tables...
--
SELECT f1 AS five FROM FLOAT8_TBL
UNION
SELECT f1 FROM FLOAT8_TBL
ORDER BY 1;
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five
-----------------------
-1.2345678901234e+200
-1004.3
-34.84
-1.2345678901234e-200
0
(5 rows)
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SELECT f1 AS ten FROM FLOAT8_TBL
UNION ALL
SELECT f1 FROM FLOAT8_TBL;
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ten
-----------------------
0
-34.84
-1004.3
-1.2345678901234e+200
-1.2345678901234e-200
0
-34.84
-1004.3
-1.2345678901234e+200
-1.2345678901234e-200
(10 rows)
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SELECT f1 AS nine FROM FLOAT8_TBL
UNION
SELECT f1 FROM INT4_TBL
ORDER BY 1;
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nine
-----------------------
-1.2345678901234e+200
-2147483647
-123456
-1004.3
-34.84
-1.2345678901234e-200
0
123456
2147483647
(9 rows)
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SELECT f1 AS ten FROM FLOAT8_TBL
UNION ALL
SELECT f1 FROM INT4_TBL;
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ten
-----------------------
0
-34.84
-1004.3
-1.2345678901234e+200
-1.2345678901234e-200
0
123456
-123456
2147483647
-2147483647
(10 rows)
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SELECT f1 AS five FROM FLOAT8_TBL
WHERE f1 BETWEEN -1e6 AND 1e6
UNION
SELECT f1 FROM INT4_TBL
WHERE f1 BETWEEN 0 AND 1000000;
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five
-----------------------
-1004.3
-34.84
-1.2345678901234e-200
0
123456
(5 rows)
SELECT CAST(f1 AS char(4)) AS three FROM VARCHAR_TBL
UNION
SELECT f1 FROM CHAR_TBL
ORDER BY 1;
three
-------
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a
ab
abcd
(3 rows)
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SELECT f1 AS three FROM VARCHAR_TBL
UNION
SELECT CAST(f1 AS varchar) FROM CHAR_TBL
ORDER BY 1;
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three
-------
a
ab
abcd
(3 rows)
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SELECT f1 AS eight FROM VARCHAR_TBL
UNION ALL
SELECT f1 FROM CHAR_TBL;
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eight
-------
a
ab
abcd
abcd
a
ab
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abcd
abcd
(8 rows)
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SELECT f1 AS five FROM TEXT_TBL
UNION
SELECT f1 FROM VARCHAR_TBL
UNION
SELECT TRIM(TRAILING FROM f1) FROM CHAR_TBL
ORDER BY 1;
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five
-------------------
a
ab
abcd
doh!
hi de ho neighbor
(5 rows)
--
-- INTERSECT and EXCEPT
--
SELECT q2 FROM int8_tbl INTERSECT SELECT q1 FROM int8_tbl;
q2
------------------
4567890123456789
123
(2 rows)
SELECT q2 FROM int8_tbl INTERSECT ALL SELECT q1 FROM int8_tbl;
q2
------------------
4567890123456789
4567890123456789
123
(3 rows)
SELECT q2 FROM int8_tbl EXCEPT SELECT q1 FROM int8_tbl ORDER BY 1;
q2
-------------------
-4567890123456789
456
(2 rows)
SELECT q2 FROM int8_tbl EXCEPT ALL SELECT q1 FROM int8_tbl ORDER BY 1;
q2
-------------------
-4567890123456789
456
(2 rows)
SELECT q2 FROM int8_tbl EXCEPT ALL SELECT DISTINCT q1 FROM int8_tbl ORDER BY 1;
q2
-------------------
-4567890123456789
456
4567890123456789
(3 rows)
SELECT q1 FROM int8_tbl EXCEPT SELECT q2 FROM int8_tbl;
q1
----
(0 rows)
SELECT q1 FROM int8_tbl EXCEPT ALL SELECT q2 FROM int8_tbl;
q1
------------------
4567890123456789
123
(2 rows)
SELECT q1 FROM int8_tbl EXCEPT ALL SELECT DISTINCT q2 FROM int8_tbl;
q1
------------------
4567890123456789
4567890123456789
123
(3 rows)
SELECT q1 FROM int8_tbl EXCEPT ALL SELECT q1 FROM int8_tbl FOR NO KEY UPDATE;
ERROR: FOR NO KEY UPDATE is not allowed with UNION/INTERSECT/EXCEPT
--
-- Mixed types
--
SELECT f1 FROM float8_tbl INTERSECT SELECT f1 FROM int4_tbl;
f1
----
0
(1 row)
SELECT f1 FROM float8_tbl EXCEPT SELECT f1 FROM int4_tbl ORDER BY 1;
f1
-----------------------
-1.2345678901234e+200
-1004.3
-34.84
-1.2345678901234e-200
(4 rows)
--
-- Operator precedence and (((((extra))))) parentheses
--
SELECT q1 FROM int8_tbl INTERSECT SELECT q2 FROM int8_tbl UNION ALL SELECT q2 FROM int8_tbl;
q1
-------------------
4567890123456789
123
456
4567890123456789
123
4567890123456789
-4567890123456789
(7 rows)
SELECT q1 FROM int8_tbl INTERSECT (((SELECT q2 FROM int8_tbl UNION ALL SELECT q2 FROM int8_tbl)));
q1
------------------
4567890123456789
123
(2 rows)
(((SELECT q1 FROM int8_tbl INTERSECT SELECT q2 FROM int8_tbl))) UNION ALL SELECT q2 FROM int8_tbl;
q1
-------------------
4567890123456789
123
456
4567890123456789
123
4567890123456789
-4567890123456789
(7 rows)
SELECT q1 FROM int8_tbl UNION ALL SELECT q2 FROM int8_tbl EXCEPT SELECT q1 FROM int8_tbl ORDER BY 1;
q1
-------------------
-4567890123456789
456
(2 rows)
SELECT q1 FROM int8_tbl UNION ALL (((SELECT q2 FROM int8_tbl EXCEPT SELECT q1 FROM int8_tbl ORDER BY 1)));
q1
-------------------
123
123
4567890123456789
4567890123456789
4567890123456789
-4567890123456789
456
(7 rows)
(((SELECT q1 FROM int8_tbl UNION ALL SELECT q2 FROM int8_tbl))) EXCEPT SELECT q1 FROM int8_tbl ORDER BY 1;
q1
-------------------
-4567890123456789
456
(2 rows)
--
-- Subqueries with ORDER BY & LIMIT clauses
--
-- In this syntax, ORDER BY/LIMIT apply to the result of the EXCEPT
SELECT q1,q2 FROM int8_tbl EXCEPT SELECT q2,q1 FROM int8_tbl
ORDER BY q2,q1;
q1 | q2
------------------+-------------------
4567890123456789 | -4567890123456789
123 | 456
(2 rows)
-- This should fail, because q2 isn't a name of an EXCEPT output column
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...
^
HINT: There is a column named "q2" in table "*SELECT* 2", 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)));
q1
------------------
4567890123456789
123
(2 rows)
--
-- New syntaxes (7.1) permit new tests
--
(((((select * from int8_tbl)))));
q1 | q2
------------------+-------------------
123 | 456
123 | 4567890123456789
4567890123456789 | 123
4567890123456789 | 4567890123456789
4567890123456789 | -4567890123456789
(5 rows)
--
-- Check handling of a case with unknown constants. We don't guarantee
-- an undecorated constant will work in all cases, but historically this
-- usage has worked, so test we don't break it.
--
SELECT a.f1 FROM (SELECT 'test' AS f1 FROM varchar_tbl) a
UNION
SELECT b.f1 FROM (SELECT f1 FROM varchar_tbl) b
ORDER BY 1;
f1
------
a
ab
abcd
test
(4 rows)
-- This should fail, but it should produce an error cursor
SELECT '3.4'::numeric UNION SELECT 'foo';
ERROR: invalid input syntax for type numeric: "foo"
LINE 1: SELECT '3.4'::numeric UNION SELECT 'foo';
^
--
-- Test that expression-index constraints can be pushed down through
-- UNION or UNION ALL
--
CREATE TEMP TABLE t1 (a text, b text);
CREATE INDEX t1_ab_idx on t1 ((a || b));
CREATE TEMP TABLE t2 (ab text primary key);
INSERT INTO t1 VALUES ('a', 'b'), ('x', 'y');
INSERT INTO t2 VALUES ('ab'), ('xy');
set enable_seqscan = off;
set enable_indexscan = on;
set enable_bitmapscan = off;
explain (costs off)
SELECT * FROM
(SELECT a || b AS ab FROM t1
UNION ALL
SELECT * FROM t2) t
WHERE ab = 'ab';
QUERY PLAN
---------------------------------------------
Append
-> Index Scan using t1_ab_idx on t1
Index Cond: ((a || b) = 'ab'::text)
-> Index Only Scan using t2_pkey on t2
Index Cond: (ab = 'ab'::text)
(5 rows)
explain (costs off)
SELECT * FROM
(SELECT a || b AS ab FROM t1
UNION
SELECT * FROM t2) t
WHERE ab = 'ab';
QUERY PLAN
---------------------------------------------------
HashAggregate
Group Key: ((t1.a || t1.b))
-> Append
-> Index Scan using t1_ab_idx on t1
Index Cond: ((a || b) = 'ab'::text)
-> Index Only Scan using t2_pkey on t2
Index Cond: (ab = 'ab'::text)
(7 rows)
--
-- Test that ORDER BY for UNION ALL can be pushed down to inheritance
-- children.
--
CREATE TEMP TABLE t1c (b text, a text);
ALTER TABLE t1c INHERIT t1;
CREATE TEMP TABLE t2c (primary key (ab)) INHERITS (t2);
INSERT INTO t1c VALUES ('v', 'w'), ('c', 'd'), ('m', 'n'), ('e', 'f');
INSERT INTO t2c VALUES ('vw'), ('cd'), ('mn'), ('ef');
CREATE INDEX t1c_ab_idx on t1c ((a || b));
set enable_seqscan = on;
set enable_indexonlyscan = off;
explain (costs off)
SELECT * FROM
(SELECT a || b AS ab FROM t1
UNION ALL
SELECT ab FROM t2) t
ORDER BY 1 LIMIT 8;
QUERY PLAN
------------------------------------------------
Limit
-> Merge Append
Sort Key: ((t1.a || t1.b))
-> Index Scan using t1_ab_idx on t1
-> Index Scan using t1c_ab_idx on t1c
-> Index Scan using t2_pkey on t2
-> Index Scan using t2c_pkey on t2c
(7 rows)
SELECT * FROM
(SELECT a || b AS ab FROM t1
UNION ALL
SELECT ab FROM t2) t
ORDER BY 1 LIMIT 8;
ab
----
ab
ab
cd
dc
ef
fe
mn
nm
(8 rows)
reset enable_seqscan;
reset enable_indexscan;
reset enable_bitmapscan;
-- This simpler variant of the above test has been observed to fail differently
create table events (event_id int primary key);
create table other_events (event_id int primary key);
create table events_child () inherits (events);
explain (costs off)
select event_id
from (select event_id from events
union all
select event_id from other_events) ss
order by event_id;
QUERY PLAN
----------------------------------------------------------
Merge Append
Sort Key: events.event_id
-> Index Scan using events_pkey on events
-> Sort
Sort Key: events_child.event_id
-> Seq Scan on events_child
-> Index Scan using other_events_pkey on other_events
(7 rows)
drop table events_child, events, other_events;
reset enable_indexonlyscan;
Revisit handling of UNION ALL subqueries with non-Var output columns. In commit 57664ed25e5dea117158a2e663c29e60b3546e1c I tried to fix a bug reported by Teodor Sigaev by making non-simple-Var output columns distinct (by wrapping their expressions with dummy PlaceHolderVar nodes). This did not work too well. Commit b28ffd0fcc583c1811e5295279e7d4366c3cae6c fixed some ensuing problems with matching to child indexes, but per a recent report from Claus Stadler, constraint exclusion of UNION ALL subqueries was still broken, because constant-simplification didn't handle the injected PlaceHolderVars well either. On reflection, the original patch was quite misguided: there is no reason to expect that EquivalenceClass child members will be distinct. So instead of trying to make them so, we should ensure that we can cope with the situation when they're not. Accordingly, this patch reverts the code changes in the above-mentioned commits (though the regression test cases they added stay). Instead, I've added assorted defenses to make sure that duplicate EC child members don't cause any problems. Teodor's original problem ("MergeAppend child's targetlist doesn't match MergeAppend") is addressed more directly by revising prepare_sort_from_pathkeys to let the parent MergeAppend's sort list guide creation of each child's sort list. In passing, get rid of add_sort_column; as far as I can tell, testing for duplicate sort keys at this stage is dead code. Certainly it doesn't trigger often enough to be worth expending cycles on in ordinary queries. And keeping the test would've greatly complicated the new logic in prepare_sort_from_pathkeys, because comparing pathkey list entries against a previous output array requires that we not skip any entries in the list. Back-patch to 9.1, like the previous patches. The only known issue in this area that wasn't caused by the ill-advised previous patches was the MergeAppend planning failure, which of course is not relevant before 9.1. It's possible that we need some of the new defenses against duplicate child EC entries in older branches, but until there's some clear evidence of that I'm going to refrain from back-patching further.
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-- Test constraint exclusion of UNION ALL subqueries
explain (costs off)
SELECT * FROM
(SELECT 1 AS t, * FROM tenk1 a
UNION ALL
SELECT 2 AS t, * FROM tenk1 b) c
WHERE t = 2;
QUERY PLAN
---------------------------
Append
-> Seq Scan on tenk1 b
(2 rows)
Revisit handling of UNION ALL subqueries with non-Var output columns. In commit 57664ed25e5dea117158a2e663c29e60b3546e1c I tried to fix a bug reported by Teodor Sigaev by making non-simple-Var output columns distinct (by wrapping their expressions with dummy PlaceHolderVar nodes). This did not work too well. Commit b28ffd0fcc583c1811e5295279e7d4366c3cae6c fixed some ensuing problems with matching to child indexes, but per a recent report from Claus Stadler, constraint exclusion of UNION ALL subqueries was still broken, because constant-simplification didn't handle the injected PlaceHolderVars well either. On reflection, the original patch was quite misguided: there is no reason to expect that EquivalenceClass child members will be distinct. So instead of trying to make them so, we should ensure that we can cope with the situation when they're not. Accordingly, this patch reverts the code changes in the above-mentioned commits (though the regression test cases they added stay). Instead, I've added assorted defenses to make sure that duplicate EC child members don't cause any problems. Teodor's original problem ("MergeAppend child's targetlist doesn't match MergeAppend") is addressed more directly by revising prepare_sort_from_pathkeys to let the parent MergeAppend's sort list guide creation of each child's sort list. In passing, get rid of add_sort_column; as far as I can tell, testing for duplicate sort keys at this stage is dead code. Certainly it doesn't trigger often enough to be worth expending cycles on in ordinary queries. And keeping the test would've greatly complicated the new logic in prepare_sort_from_pathkeys, because comparing pathkey list entries against a previous output array requires that we not skip any entries in the list. Back-patch to 9.1, like the previous patches. The only known issue in this area that wasn't caused by the ill-advised previous patches was the MergeAppend planning failure, which of course is not relevant before 9.1. It's possible that we need some of the new defenses against duplicate child EC entries in older branches, but until there's some clear evidence of that I'm going to refrain from back-patching further.
2012-03-16 18:11:12 +01:00
-- Test that we push quals into UNION sub-selects only when it's safe
explain (costs off)
SELECT * FROM
(SELECT 1 AS t, 2 AS x
UNION
SELECT 2 AS t, 4 AS x) ss
WHERE x < 4;
QUERY PLAN
--------------------------------------------
Unique
-> Sort
Sort Key: (1), (2)
-> Append
-> Result
-> Result
One-Time Filter: false
(7 rows)
SELECT * FROM
(SELECT 1 AS t, 2 AS x
UNION
SELECT 2 AS t, 4 AS x) ss
WHERE x < 4;
t | x
---+---
1 | 2
(1 row)
explain (costs off)
SELECT * FROM
(SELECT 1 AS t, generate_series(1,10) AS x
UNION
SELECT 2 AS t, 4 AS x) ss
WHERE x < 4
ORDER BY x;
QUERY PLAN
--------------------------------------------------------
Sort
Sort Key: ss.x
-> Subquery Scan on ss
Filter: (ss.x < 4)
-> HashAggregate
Group Key: (1), (generate_series(1, 10))
-> Append
-> Result
-> Result
(9 rows)
SELECT * FROM
(SELECT 1 AS t, generate_series(1,10) AS x
UNION
SELECT 2 AS t, 4 AS x) ss
WHERE x < 4
ORDER BY x;
t | x
---+---
1 | 1
1 | 2
1 | 3
(3 rows)
explain (costs off)
SELECT * FROM
(SELECT 1 AS t, (random()*3)::int AS x
UNION
SELECT 2 AS t, 4 AS x) ss
WHERE x > 3;
QUERY PLAN
------------------------------------------------------------------------------
Subquery Scan on ss
Filter: (ss.x > 3)
-> Unique
-> Sort
Sort Key: (1), (((random() * '3'::double precision))::integer)
-> Append
-> Result
-> Result
(8 rows)
SELECT * FROM
(SELECT 1 AS t, (random()*3)::int AS x
UNION
SELECT 2 AS t, 4 AS x) ss
WHERE x > 3;
t | x
---+---
2 | 4
(1 row)
-- Test proper handling of parameterized appendrel paths when the
-- potential join qual is expensive
create function expensivefunc(int) returns int
language plpgsql immutable strict cost 10000
as $$begin return $1; end$$;
create temp table t3 as select generate_series(-1000,1000) as x;
create index t3i on t3 (expensivefunc(x));
analyze t3;
explain (costs off)
select * from
(select * from t3 a union all select * from t3 b) ss
join int4_tbl on f1 = expensivefunc(x);
QUERY PLAN
------------------------------------------------------------
Nested Loop
-> Seq Scan on int4_tbl
-> Append
-> Index Scan using t3i on t3 a
Index Cond: (expensivefunc(x) = int4_tbl.f1)
-> Index Scan using t3i on t3 b
Index Cond: (expensivefunc(x) = int4_tbl.f1)
(7 rows)
select * from
(select * from t3 a union all select * from t3 b) ss
join int4_tbl on f1 = expensivefunc(x);
x | f1
---+----
0 | 0
0 | 0
(2 rows)
drop table t3;
drop function expensivefunc(int);