On Mon, 2003-08-04 at 11:55, Richard Huxton wrote: > On Monday 04 August 2003 16:25, Scott Cain wrote: > [snip] > > [snip] > > You might want some checks to make sure that smin < smax, otherwise looks like > it does the job in a good clean fashion.
Good point--smin < smax generally by virtue of the application using the database, but I shouldn't assume that will always be the case. > > Glad to hear it's going to solve your problems. Two things you might want to > bear in mind: > 1. There's probably a "sweet spot" where the chunk size interacts well with > your data, usage patterns and PGs backend to give you peak performance. > You'll have to test. Yes, I had a feeling that was probably the case-- since this is an open source project, I will need to write directions for installers on picking a reasonable chunk size. > 2. If you want to search for a sequence you'll need to deal with the case > where it starts in one chunk and ends in another. I forgot about searching--I suspect that application is why I faced opposition for shredding in my schema development group. Maybe I should push that off to the file system and use grep (or BLAST). Otherwise, I could write a function that would search the chunks first, then after failing to find the substring in those, I could start sewing the chunks together to look for the query string. That could get ugly (and slow--but if the user knows that and expects it to be slow, I'm ok with that). Thanks, Scott -- ------------------------------------------------------------------------ Scott Cain, Ph. D. [EMAIL PROTECTED] GMOD Coordinator (http://www.gmod.org/) 216-392-3087 Cold Spring Harbor Laboratory ---------------------------(end of broadcast)--------------------------- TIP 8: explain analyze is your friend
