MySQL Forums
Forum List  »  InnoDB

Re: Innodb bogs down on complicated query(ies)
Posted by: Marko Mäkelä
Date: May 08, 2006 05:56AM

The "Table lock" is thread status information that is set in mysql_lock_tables(), file InnoDB generally downgrades locks requested by MySQL. InnoDB table locks are only used within LOCK TABLES, as far as I remember. MySQL tries to acquire a table lock before executing a statement. The related InnoDB methods are ha_innobase::external_lock() and ha_innobase::store_lock().

If the UPDATE cannot be done in place, InnoDB will map it to DELETE and INSERT. If the update only modifies fixed-length columns (as I would assume based on what you have disclosed), InnoDB should perform the update in-place, and no cascade should take place.

With this limited data, I'm afraid I can't help you further. As a last resort before buying support from MySQL, you could try to experiment with the innodb_max_purge_lag setting, to throttle the UPDATE statements.

Best regards,

Marko Mäkelä
Innobase Oy/Oracle Corp.

Options: ReplyQuote

Written By
Re: Innodb bogs down on complicated query(ies)
May 08, 2006 05:56AM

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.