D Morrow wrote:
>
> A while back there was a posting about size of tables and indexing. I
> thought it had mentioned that a small table (about 1000 rows) was just on
> the edge of needing an index??
>
> My question is: any general guidelines on when to create an index for a
> table
>
> thanx in advance
> Donna
Apart from primary keys....
I don't think it has anything to do with the number of
rows but instead has more to do with how much of the
data fits in the number of blocks defined by the
mulit block read count parameter. ie if the database
reads 32K for a full table scan and the entire table
fits in 32K - an index isn't very helpful since an in
memory scan is very fast - in fact using an index in
this case would likely decrease performance.
This (is hopefully correct and ) may not apply to
join situations.
Anyone else have specifics or corrections to this?
Terry
Received on Wed Oct 01 1997 - 00:00:00 CDT
