Home » Applications » Oracle Fusion Apps & E-Business Suite » Disabling hash_join_enabled (DB 9.2.0.7)
Disabling hash_join_enabled [message #292368] Tue, 08 January 2008 15:29 Go to next message
enelson
Messages: 7
Registered: January 2008
Junior Member
We have encountered bug 4401437 and Oracle's solution from note 360811.1 is to set the hash_join_enabled database property from true to false.

Has anyone else done this? What performance loss/gain did you see?
Re: Disabling hash_join_enabled [message #292487 is a reply to message #292368] Wed, 09 January 2008 01:12 Go to previous messageGo to next message
Michel Cadot
Messages: 64119
Registered: March 2007
Location: Nanterre, France, http://...
Senior Member
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If you encounter a bug and the solution is that, you have no other way than to set this parameter, so what is the interest of this question?
The result is that optimizer will no more generate plans with hash joins. Of course there will be loss of performances in some queries otherwise Oracle would not implement this access path.

Regards
Michel
Re: Disabling hash_join_enabled [message #292648 is a reply to message #292487] Wed, 09 January 2008 09:08 Go to previous messageGo to next message
enelson
Messages: 7
Registered: January 2008
Junior Member
Thanks for the reply!

Have you (or anyone for that matter) noticed a significant degradation of performance in a particular module, application or report?

Thanks!

Eric
Re: Disabling hash_join_enabled [message #292650 is a reply to message #292648] Wed, 09 January 2008 09:11 Go to previous messageGo to next message
Michel Cadot
Messages: 64119
Registered: March 2007
Location: Nanterre, France, http://...
Senior Member
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Are you talking about Oracle applications?

Regards
Michel
Re: Disabling hash_join_enabled [message #292682 is a reply to message #292650] Wed, 09 January 2008 10:57 Go to previous messageGo to next message
enelson
Messages: 7
Registered: January 2008
Junior Member
Correct. I am asking about Oracle applications and their full ERP suite.

Thanks!

Eric
Re: Disabling hash_join_enabled [message #292687 is a reply to message #292682] Wed, 09 January 2008 11:29 Go to previous messageGo to next message
Michel Cadot
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I move this topic to ERP forum in this case.

Regards
Michel
Re: Disabling hash_join_enabled [message #292892 is a reply to message #292687] Thu, 10 January 2008 02:23 Go to previous messageGo to next message
skooman
Messages: 912
Registered: March 2005
Location: Netherlands
Senior Member
Are you sure the bug number you mention is correct? Did you encounter an ORA-00600 error using an connect by prior and start with statement? In EBS?

Furthermore, the doc id you mention says to add a 'no_filtering' hint to the query, not to alter any database parameters as far as I can see. Since you can't add hints to standard EBS code, I would recommend to raise an SR on Metalink for your EBS error and let support handle it.
Re: Disabling hash_join_enabled [message #293000 is a reply to message #292892] Thu, 10 January 2008 09:14 Go to previous messageGo to next message
enelson
Messages: 7
Registered: January 2008
Junior Member
Thank you for your reply. The SR I opened with Oracle said the only solution for a 9.2.0.7 db is to disable the Hash_Join_Enabled parameter.

We have been running with this parameter enabled for some months and am satisfied with the application and conc requests performance.

Our concern is the impact to our system's performance if we disable this parameter.

Has anyone been running EBS with this parameter disabled on a 9.2.0.7 database?
Re: Disabling hash_join_enabled [message #296279 is a reply to message #293000] Fri, 25 January 2008 09:10 Go to previous message
enelson
Messages: 7
Registered: January 2008
Junior Member
A follow-up...

Oracle would not backport their bug-fix for the hash_join_enabled issue to 9.2.0.7.

Disabling this join criteria would cause issues in other aspects of the system (particularly sales order lines).

We decided to rewrite an inefficient query that was called when the Credit Management Update Case Folder button was pressed. Once we rewrote the query to limit the amount of data that had to be parsed, the db engine did not utilize the hash_join because it's cost was too high. This fixed our problem for now.

BTW...all queries for the HTML based Oracle applications are in XML files (for 11.5.10 anyways).
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