So it is possible that if I had a fast scsi drive, the performance might be better?
On Thu, 2003-07-31 at 16:31, Joe Conway wrote: > Scott Cain wrote: > > Index Scan using feature_pkey on feature (cost=0.00..3.01 rows=1 > > width=153) (actual time=954.13..954.14 rows=1 loops=1) > > Index Cond: (feature_id = 1) > > Total runtime: 954.26 msec > > (3 rows) > > > > Whoa! That's not what I expected, the time to do the query got more > > that twice as long. So I think, maybe it was just an unlucky section, > > and overall performance will be much better. So I write a perl script > > to do substring queries over all of my chromosomes at various positions > > and lengths (20,000 queries total). For comparison, I also ran the same > > script, extracting the chromosomes via sql and doing the substring in > > perl. Here's what happened: > > Hmmm, what happens if you compare with a shorter substring, e.g.: > > explain analyze select substring(residues from 1000000 for 2000) > from feature where feature_id=1; > > I'm just guessing, but it might be that the extra I/O time to read 20K > of uncompressed text versus the smaller compressed text is enough to > swamp the time saved from not needing to uncompress. > > Any other ideas out there? > > Joe -- ------------------------------------------------------------------------ Scott Cain, Ph. D. [EMAIL PROTECTED] GMOD Coordinator (http://www.gmod.org/) 216-392-3087 Cold Spring Harbor Laboratory ---------------------------(end of broadcast)--------------------------- TIP 2: you can get off all lists at once with the unregister command (send "unregister YourEmailAddressHere" to [EMAIL PROTECTED])
