fu: Close-up of Fu, bringing a scoop of water to her mouth (Default)
fu ([personal profile] fu) wrote in [site community profile] dw_dev2010-05-27 03:14 pm
Entry tags:

Batch processing of huge tables

So, I just committed a code merge for an issue we found via LJ, where comment properties weren't being deleted when the comment was.

That takes care of new properties, but we still have old ones hanging around! How do we handle this? I'm assuming that due to the size of talkprop2, doing:

delete talkprop2 from talkprop2, talk2 where talkprop2.journalid=talk2.journalid AND talkprop2.jtalkid=talk2.jtalkid AND talk2.state="D";

would be a horrible idea, but what can we do to make it less horrible? Should we even try to delete?
foxfirefey: A wee rat holds a paw to its mouth. Oh, the shock! (thoughtful)

[personal profile] foxfirefey 2010-05-27 07:37 am (UTC)(link)
Hrm....maybe there could be a worker that gets batches by the primary indexed key where talk2.state="D" and checks each one. Just slow and steady and low-key?
zorkian: Icon full of binary ones and zeros in no pattern. (Default)

[personal profile] zorkian 2010-05-27 03:07 pm (UTC)(link)
IMO not really worth worrying about. We aren't hurting for those megabytes.