Re: Performance Questions 7.x

Carol Stimmel wrote: > > HELP! > > How long can it take?! A simple query in our database > is taking a L-O-N-G time to execute. It's not > our application, because we experience the same > problem from isql. We've fragmented our tables, set > read ahead parameters, and added a couple of > page cleaners. It is definitely having a problem > with the size of the database (which is indexed, maybe > not properly ;-). We have several dbspaces that > our broken out by our fragmentation scheme and one > big blobspace: > > address chk/dbs offset size free bpages flags > 80737d20 15 15 511040 500000 ~202580 250000 POB /dev/informix-1 > > Is this the problem? Is informix just a big slow pig? > Sorry for the name-calling, but I have exactly 2 weeks to > have this system screaming, and it's not. You're help > is greatly appreciated! BTW, when I mean slow, I'm talking > 15-30 seconds to execute an sql statement and return the > data. I have a requirement of 3-10 seconds. > > What's left? We are running INFORMIX-OnLine Version 7.10.UD1 > on an HP-UX A.09.05 A 9000/755. I'm out of ideas, can > someone email or post their thoughts on how to improve > performance of our database. > > -- > Carol L. Stimmel, Systems Analyst > NOAA/ERL/FSL work: stimmel@fsl.noaa.gov > 325 Broadway home: stimmel@majordomos.com > Boulder, CO 80303 If you feel comfortable with the onconfig file paramters I would look at the way you are fragmenting. For example, let's say that you have a table with a date column and you usually look up by quarter. At first you might think to do a round robin,but actually it's faster to put a quarter on each disk (let say you have 4 disks). It's faster because it doesn't have to scan thru all the data. It knows where the information is and right there you have discarded 75% of unnecessary data. I didn't actually experience this, somebody from informix gave me the tip. I hope this helps.