RE: queries too slow

On Tue, 11 Jul 2000, Gaja Krishna Vaidyanatha wrote:

> Performance needs to be measured by "system throughput", how
> much work has the system done for you. We have even dealt with
> systems with 65-70% cache hit ratios where the performance of
> the transactions and the queries was steller. The incremental
> increase in cache hit ratio that one achieves by configuring the
> db buffer cache with more memory, does not do much to system
> performance.
>
> Hence the memory should be probably utilized for something else
> (e.g. sort_area_size, hash_area_size etc.). Like anything in
> life, the law of diminishing returns will come to play sooner or
> later. Further, the reference to a 99% cache hit ratio and the
> assumption that performance is great as a result, it not
> correct. Not by a long shot.
>

When I see >= 95% hit ratios, high physical reads and low logical reads, I assume a cartesian join and tell the duhveloper to take another look at the WHERE clause.

Jared Still
Certified Oracle DBA and Part Time Perl Evangelist ;-) Regence BlueCross BlueShield of Oregon
jkstill_at_bcbso.com - Work - preferred address jkstill_at_teleport.com - private Received on Wed Jul 12 2000 - 12:43:56 CDT