RE: Number of open cursors

Yes it can... and most times it's because of lazy programmers or poor design.

On a prior job we had a system where I set open_cursors to 1000. And on busy days we'd hit that number because the users would move from screen to screen to screen and not back out of things "properly" (when did a user ever follow the rules?)... The programmers had not closed cursors behind themselves.

Once they hit the max, we had to kill their sessions to clear it. Losing orders in the process.

Management decided that rather than fix the problem, they'd leave it like that so that they could "train" the users. Now, they always had lots of temp workers for the busy seasons, and these people were never the same ones ... so who got trained?

>From: "Jeffery Stevenson" <jeff_at_mpv.com>
>Reply-To: ORACLE-L_at_fatcity.com
>To: Multiple recipients of list ORACLE-L <ORACLE-L_at_fatcity.com>
>Subject: RE: Number of open cursors
>Date: Wed, 30 Aug 2000 12:00:58 -0800
>
>But it can happen, I ran into a situation where a vendor provided
>load/migration utility had some "minor" problems. One of these problems
>was
>that I had to set open_cursors to 25000 in order for the utility to be able
>to process one of their 20000 line files (as a workaround because the
>vendor
>didn't feel the need to fix the problem). Luckily it was only this utility
>that had this problem and not the actual application itself (it had its own
>issues to deal with), so I could cut back on the resource usage after the
>initial data loads were done.
>
>Jeffery Stevenson
>Chief Database Geek
>Medical Present Value, Inc.
>Austin, TX
>
>-----Original Message-----
>Eduard
>Sent: Wednesday, August 30, 2000 2:33 PM
>To: Multiple recipients of list ORACLE-L
>
>
>Hello Linda
>
>Please, consider that open_cursor is the per-session setting
>IMHO only in the rare situations you have to increase open_cursor up to 300
>or even more 400
>
>
>Kind regards,
>Edward
>
> > I need to find the count of cursors currently open which count against
>the
> > open_cursors limit in init.ora, and the expected behavior when the limit
>is
> > reached and/or exceeded. References to documentation or dissertations
>are
> > appreciated.
> >
> > According to the queries below, I have between 510 and 1871 cursors
>open,
> > and my init.ora limit is 200.
> >
> > I have failures in the front end web product, BroadVision, and am
>unlikely
> > to have the debug capabilities turned on from that side. I'm stuck
>trying
> > to determine SQL failures from the Oracle side. SQL trace level 4 will
>be
> > turned on in the next recycle, and I do not have control of the
>executing
> > SQL for testing purposes.
> >
> > References are welcome. If I've made something unclear, please let me
>try
> > again.
> >
> > Regards, Linda
> >
> > select count(*) from v$open_cursor;
> > COUNT(*)
> > ---------
> > 510
> >
> > select value, name from v$sysstat where statistic# in (2,3) ;
> > VALUE NAME
> > ---------
>----------------------------------------------------------------
> > 4313697 opened cursors cumulative
> > 1871 opened cursors current
> >
> > select substr(name,1,25),substr(value,1,15),isses_modifiable,
> > issys_modifiable
> > from v$parameter where name like '%cursor%' ;
> > SUBSTR(NAME,1,25) SUBSTR(VALUE,1, ISSES ISSYS_MOD
> > ------------------------- --------------- ----- ---------
> > row_cache_cursors 100 FALSE FALSE
> > close_cached_open_cursors FALSE TRUE FALSE
> > open_cursors 200 FALSE FALSE
> > cursor_space_for_time FALSE FALSE FALSE
> > session_cached_cursors 0 TRUE FALSE
> >
> >
> > Reference:
> > GV$OPEN_CURSOR select inst_id,kgllkuse, kgllksnm,
> > user_name, kglhdpar, kglnahsh, kglnaobj
> > from x$kgllk
> > where kglhdnsp = 0
> > and kglhdpar != kgllkhdl;
> >
> > V$OPEN_CURSOR select SADDR , SID , USER_NAME ,
> > ADDRESS , HASH_VALUE , SQL_TEXT
> > from GV$OPEN_CURSOR
> > where inst_id = USERENV('Instance');
> >
> >
> >
> >
> > -----Original Message-----
> > Sent: Wednesday, August 30, 2000 1:01 AM
> > To: Multiple recipients of list ORACLE-L
> >
> >
> > Hi !
> >
> > THe better picture can be obtained from
> > V$SYSSTAT because V$OPEN_CURSORS
> > will not inlde the dynamic cursor stats
> >
> > SELECT name,value from V$sysstat
> > where name like '%cursor%;
> >
> > K Gopalakrishnan
> > Bangalore, INDIA
> >
> >
> >
> >
> >
> > ----- Original Message -----
> > To: Multiple recipients of list ORACLE-L <ORACLE-L_at_fatcity.com>
> > Sent: Wednesday, August 30, 2000 4:26 AM
> >
> >
> > > You can issue
> > >
> > > SELECT COUNT(*) FROM V$OPEN_CURSOR;
> > >
> > > To be more specific, this can be selected for ALL cursors, or by SID.
> > >
> > > SELECT * FROM V$OPEN_CURSOR;
> > >
> > > Best regards,
> > >
> > > -Ari Kaplan
> > > Independent Oracle DBA Consultant
> > >
> > > <-><-><-><-><-><-><-><-><-><-><-><-><-><-><-><-><-><-><-><->
> > > <-> For 380+ Oracle tips, visit: <->
> > > <-> <->
> > > <-> www.arikaplan.com <->
> > > <-> <->
> > > <-> email: akaplan_at_interaccess.com <->
> > > <-><-><-><-><-><-><-><-><-><-><-><-><-><-><-><-><-><-><-><->
> > >
> > >
> > > On Tue, 29 Aug 2000, Linda Hagedorn wrote:
> > >
> > > > Where would I find the number of currently open cursors, instance
>wide?
> > > >
> > > > Thanks,
> > > >
> > > > Linda Hagedorn
> > > >
> > > > --
> > > > Author: Linda Hagedorn
> > > > INET: Linda_at_pets.com
> > > >
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> > > --
> > > Author: Ari D Kaplan
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> > >
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> > --
> > Author: K Gopalakrishnan
> > INET: kaygopal_at_yahoo.com
> >
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> > Author: Linda Hagedorn
> > INET: Linda_at_pets.com
> >
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>--
>Author: Shevtsov Eduard
> INET: eshevtsov_at_flagship.ru
>
>Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051
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>--
>Author: Jeffery Stevenson
> INET: jeff_at_mpv.com
>
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>San Diego, California -- Public Internet access / Mailing Lists
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Received on Thu Aug 31 2000 - 05:33:25 CDT