Re: Clustered indexes - again

robert@clark.netkonect.co.uk (Robert Clark) wrote: >OK, >I have now had a few responses to my original Q about clustered >indexes - thanks to all of you. >Dan Madvig (d-madvig@bethel.edu) said: >> If you leave it chustered, then every time the index changes >> the engine has to shuffle the data to match. If the index >> doesn't change much, it couldn't hurt. >Craig (craig.chemistry.chem.utah.edu) said: >> Creating a clustered index on a table does not affect future >> inserts or updates. That is to say, new inserts/updates ignore >> the cluster flag. So, no performance hits. (I think the only >> reason the cluster flag remains set is so you get an error if >> you try to cluster on another index.) >So given these responses I am confused. Does leaving an index >clustered effect future inserts/updates etc? >Robert Clark > >-------------------------------------------------------------- >e-mail: robert@clark.netkonect.co.uk >snail: 12 Balvernie Grove, Wandsworth, LONDON, SW18 5RU, UK. >-------------------------------------------------------------- Informix does not maintane clustering after the index build. Therefore, a normal insert or update is treated the same as it would for any other index. About the only reason to use a clustered index on a high update table in informix is to alter index to cluster to regain space without unloading and reloading the table. -- Tolly Brumbelow, Informix DBA email:tolly.brumbelow@bridge.bellsouth.com