Oracle-L: RE: cursor_sharing in 8.1.7.4

From: Spears, Brian <BSpears_at_LIMITEDBRANDS.COM>
Date: Wed, 20 Aug 2003 08:24:31 -0800
Message-ID: <F001.005CBC58.20030820082431@fatcity.com>

NO...do not use. It is bugged. I believe it is fixed in 9x. It has problems with core dumps/600 errors when executing SQL statements depending on their length. It was not fixed as of 8.1.7.3, and I seem to remember it not supposed to being fixed until 9x.

this statement might fail.

Select 'the current date is: '||sysdate from dual;

and this might succeed (only difference is an added space):

Select 'the current date is: '||sysdate from dual;

A consultant here supplied me with this info..as I was lookin at doing it for ourselves.

Brian Spears

-----Original Message-----
Sent: Tuesday, August 19, 2003 7:34 PM
To: Multiple recipients of list ORACLE-L

Point noted. Excellent posts from both you and Walt. I guess that is what the forum is for. To present one's experience without trashing someone else's point of view.

Since you have first hand experience on the latest I guess John should listen to both of you first. Thanks

"Jesse, Rich" <Rich.Jesse_at_qtiworld.com> wrote:

True, but using binds isn't always an option, like when running a 3rd party product. I also could not justify weeks of recoding homegrown software for the relatively minor gains we would have using binds. And scalability (or lack thereof) didn't seem to be argument enough.

We're using CS=F on 8.1.7.4 on HP/UX 11.0. We haven't yet had a single issue attributable to it in the 7 months we've been at the .4 release. There were some nasty issues with 8.1.7.2 (ORA-600 and silently returning WRONG data), but like I said, .4 seems to have cleaned that up. YMMV.

Remember that under 8i, you may see some performance DROP by using binds. The case that comes to mind is if you're using histograms with ANALYZE or DBMS_STATS. Under 8i, the optimizer can no longer "see" the values and therefore can't use the histograms. Under 9i (R2 only?), you can tell the optimizer to peek at the bind variables' values in order to make use of histograms. We plan on doing this when we get to 9i in order to use a very low cardinality index, where less than 0.0001% of the rows is what we need to fetch, but 8i won't use the index because of the cardinality.

Your best bet, of course, is to test! HTH! GL! :)

Rich

Rich Jesse System/Database Administrator rjesse_at_qtiworld.com Quad/Tech Inc, Sussex, WI USA

-----Original Message-----
Sent: Tuesday, August 19, 2003 2:49 PM
To: Multiple recipients of list ORACLE-L

Hi,
No. I recommend that you do not change cursor_sharing if you are doing it just to get rid of 4031. There could be serious problems. ora-600 etc. Maybe Oracle has fixed everything in latest 817 but I suggest not to take that chance.
For 4031 you can do the following : pin pl/sql sql preferably at startup, use bind variables and periodically check fo! r sql not using bind variables.
Goodluck.

"Fedock, John (KAM.RHQ)" wrote:

Does anyone have any experience using cursor_sharing in 8.1.7.4? I feel I need to use it due to literal SQL statements being used. We have had misc 4031 errors off and on and I feel this is my last hope. I have a very busy OPFS server (HP-UX).

I did try using cursor_sharing in 8.1.7.2, and I remember incorrect sorting and other unexpected results happening.

Thanks for any input.

John
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Author: Jesse, Rich
INET: Rich.Jesse_at_qtiworld.com

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Author: Spears, Brian
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RE: cursor_sharing in 8.1.7.4 - good or bad