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Bug #24484:

Browse Source 
To correctly decide which predicates can be evaluated with a given table
the optimizer must know the exact set of tables that a predicate depends 
on. If that mask is too wide (refer to non-existing tables) the optimizer
can erroneously skip a predicate.
One such case of wrong table usage mask were the aggregate functions.
The have a all-1 mask (meaning depend on all tables, including non-existent
ones).
Fixed by making a real used_tables mask for the aggregates. The mask is
constructed in the following way :
1. OR the table dependency masks of all the arguments of the aggregate.
2. If all the arguments of the function are from the local name resolution 
  context and it is evaluated in the same name resolution
  context where it is referenced all the tables from that name resolution 
  context are OR-ed to the dependency mask. This is to denote that an
  aggregate function depends on the number of rows it processes.
3. Handle correctly the case of an aggregate function optimization (such that
  the aggregate function can be pre-calculated and made a constant).

Made sure that an aggregate function is never a constant (unless subject of a 
specific optimization and pre-calculation).  

One other flaw was revealed and fixed in the process : references were 
not calling the recalculation method for used_tables of their targets.
This commit is contained in:
gkodinov/kgeorge@macbook.local
2007-03-20 19:46:02 +02:00
parent d1185aaeaf
commit 28962a76a3
10 changed files with 189 additions and 45 deletions
Download Patch File Download Diff File Expand all files Collapse all files

53
mysql-test/r/subselect3.result
View File

@ -645,3 +645,56 @@ a b Z
2 2 0
3 3 1
drop table t1,t2;
CREATE TABLE t1 (a int, b INT, c CHAR(10) NOT NULL, PRIMARY KEY (a, b));
INSERT INTO t1 VALUES (1,1,'a'), (1,2,'b'), (1,3,'c'), (1,4,'d'), (1,5,'e'),
(2,1,'f'), (2,2,'g'), (2,3,'h'), (3,4,'i'),(3,3,'j'), (3,2,'k'), (3,1,'l'),
(1,9,'m');
CREATE TABLE t2 (a int, b INT, c CHAR(10) NOT NULL, PRIMARY KEY (a, b));
INSERT INTO t2 SELECT * FROM t1;
SELECT a, MAX(b), (SELECT t.c FROM t1 AS t WHERE t1.a=t.a AND t.b=MAX(t1.b))
as test FROM t1 GROUP BY a;
a MAX(b) test
1 9 m
2 3 h
3 4 i
SELECT * FROM t1 GROUP by t1.a
HAVING (MAX(t1.b) > (SELECT MAX(t2.b) FROM t2 WHERE t2.c < t1.c
HAVING MAX(t2.b+t1.a) < 10));
a b c
SELECT a, AVG(b), (SELECT t.c FROM t1 AS t WHERE t1.a=t.a AND t.b=AVG(t1.b))
AS test FROM t1 GROUP BY a;
a AVG(b) test
1 4.0000 NULL
2 2.0000 k
3 2.5000 NULL
SELECT a,b,c FROM t1 WHERE b in (9,3,4) ORDER BY b,c;
a b c
1 3 c
2 3 h
3 3 j
1 4 d
3 4 i
1 9 m
SELECT a, MAX(b),
(SELECT COUNT(DISTINCT t.c) FROM t1 AS t WHERE t1.a=t.a AND t.b=MAX(t1.b)
LIMIT 1)
as cnt,
(SELECT t.b FROM t1 AS t WHERE t1.a=t.a AND t.b=MAX(t1.b) LIMIT 1)
as t_b,
(SELECT t.c FROM t1 AS t WHERE t1.a=t.a AND t.b=MAX(t1.b) LIMIT 1)
as t_b,
(SELECT t.c FROM t1 AS t WHERE t1.a=t.a AND t.b=MAX(t1.b) ORDER BY t.c LIMIT 1)
as t_b
FROM t1 GROUP BY a;
a MAX(b) cnt t_b t_b t_b
1 9 1 9 m m
2 3 1 3 h h
3 4 1 4 i i
SELECT a, MAX(b),
(SELECT t.c FROM t1 AS t WHERE t1.a=t.a AND t.b=MAX(t1.b) LIMIT 1) as test
FROM t1 GROUP BY a;
a MAX(b) test
1 9 m
2 3 h
3 4 i
DROP TABLE t1, t2;

41
mysql-test/t/subselect3.test
View File

@ -489,3 +489,44 @@ select a, b, (a,b) in (select a, min(b) from t2 group by a) Z from t1;
drop table t1,t2;
#
# Bug #24484: Aggregate function used in column list subquery gives erroneous
# error
#
CREATE TABLE t1 (a int, b INT, c CHAR(10) NOT NULL, PRIMARY KEY (a, b));
INSERT INTO t1 VALUES (1,1,'a'), (1,2,'b'), (1,3,'c'), (1,4,'d'), (1,5,'e'),
(2,1,'f'), (2,2,'g'), (2,3,'h'), (3,4,'i'),(3,3,'j'), (3,2,'k'), (3,1,'l'),
(1,9,'m');
CREATE TABLE t2 (a int, b INT, c CHAR(10) NOT NULL, PRIMARY KEY (a, b));
INSERT INTO t2 SELECT * FROM t1;
# Gives error, but should work since it is (a, b) is the PK so only one
# given match possible
SELECT a, MAX(b), (SELECT t.c FROM t1 AS t WHERE t1.a=t.a AND t.b=MAX(t1.b))
as test FROM t1 GROUP BY a;
SELECT * FROM t1 GROUP by t1.a
HAVING (MAX(t1.b) > (SELECT MAX(t2.b) FROM t2 WHERE t2.c < t1.c
HAVING MAX(t2.b+t1.a) < 10));
SELECT a, AVG(b), (SELECT t.c FROM t1 AS t WHERE t1.a=t.a AND t.b=AVG(t1.b))
AS test FROM t1 GROUP BY a;
SELECT a,b,c FROM t1 WHERE b in (9,3,4) ORDER BY b,c;
SELECT a, MAX(b),
(SELECT COUNT(DISTINCT t.c) FROM t1 AS t WHERE t1.a=t.a AND t.b=MAX(t1.b)
LIMIT 1)
as cnt,
(SELECT t.b FROM t1 AS t WHERE t1.a=t.a AND t.b=MAX(t1.b) LIMIT 1)
as t_b,
(SELECT t.c FROM t1 AS t WHERE t1.a=t.a AND t.b=MAX(t1.b) LIMIT 1)
as t_b,
(SELECT t.c FROM t1 AS t WHERE t1.a=t.a AND t.b=MAX(t1.b) ORDER BY t.c LIMIT 1)
as t_b
FROM t1 GROUP BY a;
SELECT a, MAX(b),
(SELECT t.c FROM t1 AS t WHERE t1.a=t.a AND t.b=MAX(t1.b) LIMIT 1) as test
FROM t1 GROUP BY a;
DROP TABLE t1, t2;