Re: Parallel Query Option causes excessive paging on DEC Unix 3.0 (Alpha)

Marty Himmelstein <marty.himmelstein_at_valley.net> wrote:

>I recently upgraded from 7.1.4 to 7.2.2 on a DEC Unix 3.0 Alpha platform.
>The Alpha is a 4-CPU system with 640 megabytes of physical memory. The SGA is about
>250 megabytes, mostly buffers. When the following problems occurred, nothing else
>was running on the system. A query such as:
>
> select count(*) from table where date-attribute between startDate and endDate
 

>caused excessive page-in activity. This did not happen on 7.1.4. The table is
>defined with parallel(degree 3). The paging does not occur if less than 3 PQO
>servers are initiated. It seems that each PQ server process is paging in stuff that
>should be shared. The resident working set of each PQ server is about 210
>megabytes, but most of this is probably the SGA, which is a shared segment. It
>almost seems that each PQ server is dealing with a private SGA!
 

>This is a serious problem, and not one that was caused by an exotic combination of
>factors. (How could this get past Oracle's QA? ) I'd appreciate any help.
 

>Thanks,
>Marty Himmelstein
>marty.himmelstein_at_valley.net

Have you checked your SORT_AREA_SIZE? Received on Sun Dec 24 1995 - 00:00:00 CET