RE: Pinning/keeping plans in shared pool

Thanks Mark - you were right on, I did miss the lower portion of Boris' email. I had read Tanel's comments earlier though and also the white paper that Tanel referenced, and my understanding from both was that cursor_space_for_time=true *does* make the plan/heap6 stay pinned along with the metadata/heap0, but *only* as long as the cursor is open - here are the pertinent statements from the white paper (available here: http://download-west.oracle.com/oowsf2005/003wp.pdf):

p.18: "Cursor_space_for_time is an initialization parameter which can be used for optimizing the repeated execution of cursors that are parsed once and kept open. The distinction is important: the cursor must remain open for cursor_space_for_time to apply" . . . "Unlike session_cached_cursors where only heap 0 of the cursor is pinned, with cursor_space_for_time we pin the entire cursor in the pool until the cursor is closed"

So if this white paper is correct, then cursor_space_for_time=true won't help in my case because the cursor is closed after execution. I might test it though just to be sure - maybe there is some special effect that the white paper fails to mention when cursor_space_for_time=true is used in conjunction with dbms_shared_pool.keep.

Regards,
Brandon

-----Original Message-----

From: Bobak, Mark [mailto:Mark.Bobak_at_il.proquest.com] Sent: Monday, July 10, 2006 6:34 AM
To: Allen, Brandon; Boris Dali; rjamya_at_gmail.com; tanel.poder.003_at_mail.ee
Cc: oracle-l_at_freelists.org
Subject: RE: Pinning/keeping plans in shared pool

Brandon,

I think Boris's reply, where he asked if you have cursor_space_for_time = true, explains why he thinks it will help.

If you look at that posting more carefully, after he asks the question, there is a bunch of quoted material from Tanel as well as some of Boris's comments. (I suspect you just read his one-liner question, and assumed everything below the "------" was old quoted material, which isn't the case.)

I think you ought to try cursor_space_for_time=true.

-Mark

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Mark J. Bobak
Senior Oracle Architect
ProQuest Information & Learning

Ours is the age that is proud of machines that can think and suspicious of men who try to. --H. Mumford Jones, 1892-1980

-----Original Message-----

From: oracle-l-bounce_at_freelists.org
[mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Allen, Brandon Sent: Saturday, July 08, 2006 5:20 PM
To: Boris Dali; rjamya_at_gmail.com; tanel.poder.003_at_mail.ee Cc: oracle-l_at_freelists.org
Subject: RE: Pinning/keeping plans in shared pool

I have cursor_space_for_time set to false (default). I thought about trying with it set to true, but if I understand the documentation correctly, this only affects cursors that are still open - which won't help in my case. Someone please correct me if I'm wrong on that.

Thanks

-----Original Message-----

From: Boris Dali [mailto:boris_dali_at_yahoo.ca] Sent: Saturday, July 08, 2006 9:55 AM
To: Allen, Brandon; rjamya_at_gmail.com; tanel.poder.003_at_mail.ee Cc: oracle-l_at_freelists.org
Subject: RE: Pinning/keeping plans in shared pool

Brandon,

What's your cursor_space_for_time setting? Does setting it true make any difference?

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http://www.freelists.org/webpage/oracle-l Received on Mon Jul 10 2006 - 10:48:16 CDT