MySQL Forums
Forum List  »  Performance

Re: Selects are slow when blob field?
Posted by: Harrison Fisk
Date: November 24, 2004 05:05PM

Hi,

If you are always retrieving the blob data, then it wouldn't matter. Obviously in order to retrieve the blob it is going to have to read disk to get it. However long it takes to read 8MB of data will always be a bottleneck in your query, even with totally proper indexing (which should still help some).

If you do a bit of math you can see that with 8MB*28rows=224MB of data is being read and returned by the query you mentioned. No matter how fast your disk/network is, it will take a bit of time to move all of that data. If this is an issue, perhaps you should think about redesigning your application to avoid this bottleneck.

Harrison Fisk, Trainer and Consultant
MySQL AB, www.mysql.com

Options: ReplyQuote


Subject
Views
Written By
Posted
5150
November 23, 2004 09:37AM
3857
November 23, 2004 09:51AM
3274
November 23, 2004 11:17AM
3362
November 23, 2004 05:29PM
3365
November 24, 2004 08:20AM
Re: Selects are slow when blob field?
3513
November 24, 2004 05:05PM
3175
November 26, 2004 10:00AM
7579
November 26, 2004 10:41AM


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.