MySQL Forums
Forum List  »  Performance

Re: Mysql too Slow when Copying to Tmp Table
Posted by: Rick James
Date: November 11, 2012 12:30PM

<opinion>
Profile seems to always highlight "Copying to tmp table", which says nothing useful. Hence, I never use Profile.
</opinion>

I really need the schema, engine type, table sizes, and EXPLAIN to help you further; please provide
* SHOW CREATE TABLE tbl\G -- engine, indexes
* SHOW TABLE STATUS LIKE 'tbl'\G -- sizes
* EXPLAIN SELECT ...\G -- clues of inefficiencies
* SHOW VARIABLES LIKE '%buffer%'; -- cache size
and surround them with [ code ] and [ / code ]

The query needs to scan one table entirely, then reach into the other table for each row. If the tables are large, it will take time. However, some tricks may be possible.

Options: ReplyQuote


Subject
Views
Written By
Posted
12168
November 10, 2012 07:57AM
Re: Mysql too Slow when Copying to Tmp Table
6249
November 11, 2012 12:30PM


Sorry, you can't reply to this topic. It has been closed.

Content reproduced on this site is the property of the respective copyright holders. It is not reviewed in advance by Oracle and does not necessarily represent the opinion of Oracle or any other party.