Re: simple query not using index

From: Dave Grzebien <dgrzebie_at_columbus.rr.com>
Date: 2000/04/18
Message-ID: <38FBC05B.2A1FAC0C@columbus.rr.com>#1/1

The problem here is that the column USER_ID has very low cardinality. Based on what you indicate here, I believe the table in question has a total of 4875 records. Unfortunately, the query is looking for a value that is about 19% of the whole table.

One thing to look at would be the value in USER_INDEXES.DISTINCT_KEYS. If I were to base the value from the statistics in the issue, you might only find a value of 5 or 6 for distinct values. This is not great selectivity.

Dave

MMayer3077 wrote:

> Yes try making it a value like 4 or 5.
> Your # of records was <10,000. This would correspond to a size of 6 integer
> value or 10's columns in decimal math. If are currently reserving
> 1,000,000,000,000,000,000,000,000,000,000,000,000 places in memory then your
> index will be not be efficent.
Received on Tue Apr 18 2000 - 00:00:00 CDT