Re: using indexes

From: Sybrand Bakker <postbus_at_sybrandb.demon.nl>
Date: Thu, 7 Dec 2000 18:33:18 +0100
Message-ID: <90ol0s$1qcsm$5@ID-62141.news.dfncis.de>

That is exactly why Oracle has a built-in optimizer. If you create histograms for your data, it will automatically use a full table scan when more than 5 percent of the table needs to be read. You can create histograms by issuing
analyze table <table_name> compute statistics for all indexed columns.

Regards,

Sybrand Bakker, Oracle DBA

<letokai_at_my-deja.com> wrote in message news:90ofte$llf$1_at_nnrp1.deja.com...
> I've read that the use of indexes was efficient only if the value
> selected is not frequent in the table and that it costs very much if
> it's frequent
>
> is there a way to know if this value is frequent or not?
> I mean if you have a generic program that does not know what's in the
> table it's reading? Is there a way for that program to know if using
> the index will be good or not?
>
>
> Sent via Deja.com http://www.deja.com/
> Before you buy.
Received on Thu Dec 07 2000 - 11:33:18 CST