On Tue, 5 Aug 2003, Alexander Keremidarski wrote: > MySQL will never use any index for small tables. With just few rows using index > adds overhead only. Table scan is faster in such cases. This is docummented > behaviour.
is 100,000 rows small? my simple OR queries take longer than a second. mysql> create temporary table x (y int, z int, index (y, z)); insert into x select f1,f2 from myrealtable; alter table x add q int; explain select * from x where y = 1 or z = 1; Query OK, 0 rows affected (0.00 sec) Query OK, 101200 rows affected (1.95 sec) Records: 101200 Duplicates: 0 Warnings: 0 Query OK, 101200 rows affected (1.61 sec) Records: 101200 Duplicates: 0 Warnings: 0 +-------+------+---------------+------+---------+------+--------+-------------+ | table | type | possible_keys | key | key_len | ref | rows | Extra | +-------+------+---------------+------+---------+------+--------+-------------+ | x | ALL | y | NULL | NULL | NULL | 101200 | Using where | +-------+------+---------------+------+---------+------+--------+-------------+ 1 row in set (0.00 sec) -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
