Re: Oracle PQO

Anurag,

> i) Oracle manual says that to achieve parallel procesing they
> have added one more access method ie ROWID range scan but when
> I do an explain plan of SQL statement with degree clause in it
> It does not show any usage of the above . Is there anything which
> I might be missing ( some hint clause ? ) .

Oracle does partition the table into ROWID ranges for the parallel slave processes, but this doesn't show up as such in the explain plan. What you will see is the SQL used by the parallel slaves in the OTHER column. This SQL will show the rowid range criteria.

> ii) When I run the SQL statement with degree clause in it it
> creates as many processes as I have specified in degree clause but
> surprisingly it does not terminate the SQL processes once I have
> exited from SQL*Plus . Does it mean I will have to regularly clear
> up the processes or is there some other way out ?

When the database starts up, PARALLEL_MIN_SERVERS will be created. As parallel SQL is executed, the number of slaves may increase up to

PARALLEL_MAX_SERVERS.  If a slave process is idle for more than
PARALLEL_SERVER_IDLE_TIME minutes and there are more than
PARALLEL_MIN_SERVERS active it will be removed.

-- 
Guy Harrison

gharriso@werple.net.au || http://werple.net.au/~gharriso || 613 419377964