Re: OWS performance problem

Guy The problem is the 'matches' with a wildcard. It's a known fact that if you use matches or like with an initial wildcard the optimiser won't use an index. I've not seen any discussion as to what it will do in your case, where you have a composite index and you're doing a matches on the second index element. My guess would be that you also have an index on column A alone and this is the one it's using (ie. it uses this index to isolate all rows where A = "X" and for each of these it reads the row to see if B matches "*Y*". This might well be slowerr than a table scan. If you post the actual query and the sqexplain output I might be able to help some more. Peter Whittleton (whittle@ssax.com) > > Hi > > I have an Informix Online Workgroup server 7.20.UC2 on SCO Unix 5.0.2 > After first install, it was dead slow. I did an update statistics high > and it worked much quicker. > > matches "*Y*" it takes > minutes before i have an answer. If I drop the index, it is much > quicker. > > sqexlain.out says that with the index, OWS uses the index, without, he > does a seq.scan. I changed OPTCOMPIND to 0, I did an update statistics > high on A and on B without result. > > HELP ! > > Guy >