Re: tkprof and tuning question

In article <1996Feb2.141909.2394_at_chemabs.uucp>, "Bill F. Schuyler (x3057)" <wfs21_at_cas.org> writes
>Posting this on behalf of a developer, thanks for any help!
>
>In Appendix B (Pg B 5 ) of the Application Devloper's Guide, there is a
>list of parameters that are available from tkprof. Three are of interest
>to I/O performance which are as follows
>
>EXEDSK - physical reads
>EXEQRY - consistent mode block reads
>EXECU - current mode block reads
>
>The first one is obvious but what happens within Oracle relative to objects
>(ie. SGA, rollback segs, etc.) to generate the second two? In the Admin
>Guide (PG 21-17) it also talks about "db block gets" and "consistent gets"
>but they are not defined. I believe that these may be the same two
>parameters of interest above. The point here is "how can you optimize
>something you can't define?"
>

The consistent gets are the blocks which have been reconstructed via rollback segment to enforce read consistency. That is, the rollback segment is used to reconstruct the data set applicable to your query at the time your query started. If lots of changes are being made to data on the system, this figure should increase.

The current gets are taken directly from the table being queried these values are already valid for the time your query started.

Hope this helps.
Clive Bostock

All opions expressed are those of my
own and not my employer. Received on Sat Feb 10 1996 - 00:00:00 CET