[EMAIL PROTECTED] wrote:
Ben Clewett <[EMAIL PROTECTED]> writes:
D. Richard Hipp wrote:
MySQL and PostgreSQL will use the indexes here, and therefore return the
result considerably faster.
Really? I would be very interested to know what
query plan MySQL and PostgreSQL use in this example.
It looks like I didn't look before leaping. MySQL does do a sequential
search through all rows in table with same example.
But PostgreSQL does use indexes for the same example.
You can get the PostgreSQL query plan by issuing this query:
EXPLAIN SELECT * FROM a WHERE f1 = 1 OR f2 = 1;
The output from that command is what Dr. Hipp requested.
Derrell
Ok,
From MySQL with 310606 rows:
+----+-------------+-------+------+---------------+------+---------+------+--------+-------------+
| id | select_type | table | type | possible_keys | key | key_len | ref
| rows | Extra |
+----+-------------+-------+------+---------------+------+---------+------+--------+-------------+
| 1 | SIMPLE | a | ALL | a_f1,a_f2 | NULL | NULL |
NULL | 310606 | Using where |
+----+-------------+-------+------+---------------+------+---------+------+--------+-------------+
From PSql with 2534 rows:
QUERY PLAN
-------------------------------------------------------------------------
Index Scan using a_f1, a_f2 on a (cost=0.00..39.86 rows=1003 width=12)
Index Cond: ((f1 = 1) OR (f2 = 1))
Regards,
