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Bug #22367: Optimizer uses ref join type instead of eq_ref for simple join on

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MySQL is setting the flag HA_END_SPACE_KEYS for all the keys that reference
text or varchar columns with collation different than binary.
This was done to handle correctly the situation where a lookup on such a key
may return more than 1 row because of the presence of many rows that differ
only by the amount of trailing space in the table's string column.
Inserting such values however appears to violate the unique checks on 
INSERT/UPDATE. Thus that flag must not be set as it will prevent the optimizer
from choosing a faster access method.
This fix removes the setting of the HA_END_SPACE_KEYS flag.
This commit is contained in:
gkodinov/kgeorge@macbook.gmz
2006-10-16 18:09:58 +03:00
parent df1376a542
commit a1310d84be
6 changed files with 38 additions and 9 deletions
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10
mysql-test/r/select.result
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@ -3517,3 +3517,13 @@ id a b c d e
2 NULL NULL NULL 2 40
2 NULL NULL NULL 2 50
DROP TABLE t1,t2,t3;
CREATE TABLE t1 (a int, b varchar(20) NOT NULL, PRIMARY KEY(a));
CREATE TABLE t2 (a int, b varchar(20) NOT NULL,
PRIMARY KEY (a), UNIQUE KEY (b));
INSERT INTO t1 VALUES (1,'a'),(2,'b'),(3,'c');
INSERT INTO t2 VALUES (1,'a'),(2,'b'),(3,'c');
EXPLAIN SELECT t1.a FROM t1 LEFT JOIN t2 ON t2.b=t1.b WHERE t1.a=3;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 const PRIMARY PRIMARY 4 const 1
1 SIMPLE t2 const b b 22 const 1 Using index
DROP TABLE t1,t2;