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MDEV-5606: range optimizer: "x < y" is sargable, while "y > x" is not

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Port to mariadb-1.0 the following fix from mysql-5.6:

  Revision ID: jorgen.loland@oracle.com-20120314131055-ml54x9deueqfsff4
  BUG#13701206: WHERE A>=B DOES NOT GIVE SAME EXECUTION PLAN
                AS WHERE B<=A (RANGE OPTIMIZER)
 
that fix didn't have a public testcase, so I created one.
This commit is contained in:
Sergey Petrunya
2014-02-04 13:27:10 +04:00
parent 4d5f5f4cdf
commit 75a3527777
4 changed files with 112 additions and 11 deletions
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31
mysql-test/r/range.result
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@ -2046,3 +2046,34 @@ f1 f2 f3 f4
10 0 0 0
DROP TABLE t1;
DROP VIEW v3;
#
# MDEV-5606: range optimizer: "x < y" is sargable, while "y > x" is not
#
create table t1(a int);
insert into t1 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
create table t2(a int);
insert into t2 select A.a + B.a* 10 + C.a * 100 from t1 A, t1 B, t1 C;
alter table t2 add key(a);
# Should have "range checked for each table" for second table:
explain select * from t1, t2 where t2.a < t1.a;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 10
1 SIMPLE t2 ALL a NULL NULL NULL 1000 Range checked for each record (index map: 0x1)
# Should have "range checked for each table" for second table:
explain select * from t1, t2 where t1.a > t2.a;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 10
1 SIMPLE t2 ALL a NULL NULL NULL 1000 Range checked for each record (index map: 0x1)
create table t3 (a int primary key, b int);
insert into t3 select a,a from t1;
# The second table should use 'range':
explain select * from t3, t2 where t2.a < t3.b and t3.a=1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t3 const PRIMARY PRIMARY 4 const 1
1 SIMPLE t2 range a a 5 NULL 1 Using where; Using index
# The second table should use 'range':
explain select * from t3, t2 where t3.b > t2.a and t3.a=1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t3 const PRIMARY PRIMARY 4 const 1
1 SIMPLE t2 range a a 5 NULL 1 Using where; Using index
drop table t1,t2,t3;