When to run batch in parallel?
- From: Charlotte Hammond <charlottejanehammond@xxxxxxxxx>
- To: oracle-l@xxxxxxxxxxxxx
- Date: Mon, 24 May 2010 11:14:26 -0700 (PDT)
We've got a long running batch job. Tracing shows 95% of the time is I/O waits
(mostly scattered reads steming from hash joins) against our SAN. Our
architect wants to split it into several parallel streams but I'm dubious.
Surely the SAN won't serve up data any faster just because we're running in
parallel.
Is there any benefit in this strategy? I would expect parallelism to come into
play if there's significant non-I/O time (e.g. busy on CPU) where other
sessions could take advantage of the burstiness, or if the database was
accessing multiple disks directly, not virtualised over a big SAN cache. I
reckon we just need a faster SAN (and/or some SQL tuning).
Any comments?
Many thanks
Charlotte
--
//www.freelists.org/webpage/oracle-l
Other related posts:
