Re: Enough of the "DB2" thread, let's talk about Fragmented Tables

Hi, depending on your fragmentation schema and the queries, you may get "fragment elimination", i.e. IDS finds out that it may not need to read certain fragments at all, since there will not be any data in these fragments that match the query. If fragment elimination happens, you'll probably have less I/O, no matter where on the SAN the fragments are. (Of course there's no fragment elimination for round robin fragmentation.) Apart from that check out the release notes. There are limits documented, among them the maximum number of rows in a table (fragment) (i.e. maximum row id). If you'll soon get higher that that maximum you'll have to fragment\\ the table anyway ... Regards, Martin -- Martin Fuerderer IBM Informix Development Munich, Germany Information Management owner-informix-list@iiug.org wrote on 28.07.2005 15:09:47: > > With the use of SANs for storing the database how effective will the use of > fragmented tables be? I've got a few very large tables (16+ chunks) and was > considering splitting it into 6-8 fragments, they all have serial columns > and one has 7 indexes (or is it indeces). The last time I did anything real > with them was splitting a table across 4 disks, it improved the performance > no end. I'm not convinced I will get an improvement when using a SAN > > Regards > > Colin sending to informix-list