<snip>
> Heikki> Well, mystery solved :). Except that why MySQL uses hours to
> Heikki> sieve away the extraneous rows in the first query.
>
> To be able to answer the question why:
>
> SELECT COUNT(*) FROM table1 WHERE col1=0 and col2=0
>
> Is slow, I would need to get an EXPLAIN for this query.
mysql> explain select count(*) from messages where clean=0 and
parentmsgid=0;
+----------+-------+---------------+-------------+---------+------+---------
+-------------------------+
| table | type | possible_keys | key | key_len | ref | rows
| Extra |
+----------+-------+---------------+-------------+---------+------+---------
+-------------------------+
| messages | index | parentmsgid | parentmsgid | 5 | NULL | 7207120
| where used; Using index |
+----------+-------+---------------+-------------+---------+------+---------
+-------------------------+
It appears that it is using the index, but it takes a very long time to
complete..
Thanks,
ryan
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