Re: performance impact of index

Gordon a écrit :

> Hi,
>
> I have a schema which is highly denormalized and purely read-only. For the
> purpose of fast data access, is there any reason not to create a bitmap
> index on every field for every table?
>
> Gordon
>
>
I your schema is purely read-only, you can create as much indexes as you [Quoted] want. But bitmapped indexes are only useful when the cardinality is relatively low (about 1.000 distinct values max). In other cases (more than one thousand distinct values for the column), it can be better to use b-tree indexes, but don't forget that the storage needed is much bigger.
You can alos deal with function-based indexes if you want. . Received on Sun May 23 2004 - 21:53:28 CEST