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RE: Pinning/keeping plans in shared pool

From: Allen, Brandon <>
Date: Mon, 10 Jul 2006 08:48:16 -0700
Message-ID: <04DDF147ED3A0D42B48A48A18D574C45059E1A69@NT15.oneneck.corp>

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:

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.


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

From: Bobak, Mark [] Sent: Monday, July 10, 2006 6:34 AM
To: Allen, Brandon; Boris Dali;;
Subject: RE: Pinning/keeping plans in shared pool


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 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-----

[] On Behalf Of Allen, Brandon Sent: Saturday, July 08, 2006 5:20 PM
To: Boris Dali;; Cc:
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.


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

From: Boris Dali [] Sent: Saturday, July 08, 2006 9:55 AM
To: Allen, Brandon;; Cc:
Subject: RE: Pinning/keeping plans in shared pool


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

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-- Received on Mon Jul 10 2006 - 10:48:16 CDT

Original text of this message