Re: what is too many indexes

Tam Mclaughlin wrote: > > Some of our tables have 12, 14 , 16 or more indexes on them. I have always > being told and belived that too many indexes and indexes of the wrong kind > can slow queries down i.e. indexes can take up loads of disk space and can > become skewed etc .... Unfortunately, I cant find much info in the informix > manuals to support this in detail. Can anyone refer me to another manual or > source of information where I can find out more about indexes and > performance. > > Thanks. They won't slow down queries (mostly they will speed them up), however they WILL take up disk space and significantly slow down inserts and updates. IE: if the table is fairly static and most access is read-only (queries), then a lot of indices are not a problem. If, on the other hand, the table is "hot" (frequently inserted or updated), then too many indices will slow things down. Performance testing with a loaded database is the only sure way to tell if the degradation is excessive for your application. -Bill Boyle