On Jan 3, 2007, at 2:00 AM, Steve Atkins wrote:
Holding a lock while generating the thumbnail doesn't sound like a great idea, and I think that the select for update will end up serialising the requests. I'd add a "rendering" field, text, defaulting to an empty string. Then do a "select for update where ... and rendering = '' limit 1", update the rendering field to the hostname of the box doing the work and commit. Render the thumbnail. Delete the record. That'll also give you an easy way to show status of which box is rendering which scene. Depending on what else you're putting into the where clause a partial index on something for records where rendering='' might be helpful.
this is more or less how we do it, so i second this.we also use NOTIFY/LISTEN to "wake up" the job processors when new work is added.
smime.p7s
Description: S/MIME cryptographic signature
