Home » RDBMS Server » Performance Tuning » Parallel Query yields High Consistent Gets vs Serial (Oracle RDBMS 9.2.7)
Parallel Query yields High Consistent Gets vs Serial [message #277619] Tue, 30 October 2007 17:44 Go to next message
mdoakes42
Messages: 5
Registered: May 2006
Junior Member
We are seeing performance issues with parallel query on a partitioned table with data loaded using direct parallel 8 inserts.

If we run the same query using serial (no parallel) we get better performance. (Resources are not a problem as we are running this on test and the OS is showing no issues. We've also duplicated the problem on multiple instances)

When you compare the consistent gets between the 2 queries, we see a significant higher number with parallel query then with single threaded.

For partitions that were loaded "conventionally" we see no problems with performance even with the same exact queries.

The problem seems to be with parallel direct insert and then using parallel query to access the data.

has anyone seen this? I've been examining the trace files but not sure what to look for?

We're running oracle 9.2.7 on solaris 8
Thanks
Re: Parallel Query yields High Consistent Gets vs Serial [message #277620 is a reply to message #277619] Tue, 30 October 2007 17:48 Go to previous message
BlackSwan
Messages: 25033
Registered: January 2009
Location: SoCal
Senior Member
>I've been examining the trace files but not sure what to look for?
Post the EXPLAIN PLANS for both the "good" & "bad" SQL (formatted with <code tags>).
If you collect fresh statistics after the load does anything change?
What percentage of the table rows count change by the load?
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