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Home -> Community -> Mailing Lists -> Oracle-L -> Re: Shared pool wait for library cache pin
Cherie,
Sounds like a bug:
http://metalink.oracle.com/metalink/plsql/ml2_documents.showDocument?p_database_id=NOT&p_id=132632.1
1193003
This problem was introduced in Oracle 8.1.5
SQL statements may not be shared when they should be. This can increase
shared pool latch and library cache latch
contention
You may need to upgrade the ol database.
Jared
Cherie_Machler
@gelco.com To: Jared.Still_at_radisys.com
cc: Oracle-L_at_fatcity.com
01/03/02 05:37 Subject: Re: Shared pool wait for library
cache pin
AM
Jared,
We were seeing from 2 or 3 up to a dozen shared pool waits at a time for about 200 users.
We normally haven't been seeing shared pool waits at all on this application. It was an unusual one to investigate.
Our developer was extremely concerned about this issue and brought it to our attention. Eventually the problem peaked at mid-day and performance for our end-users was twice as slow for people using the web-based app.
We finally flushed the shared pool and all the waits cleared right up. Performance on an overnight batch job that had been creeping up longer and longer was six times faster.
Must be some sort of shared memory leak or open cursor problem. We're looking at the SQL with a lot of open cursors but after flushing the shared pool, there didn't seem to be an inordinent amount of open cursors for the number of users out there.
We also bounced the database last night during our weekly maintenance window in order to clean everything our.
Today we are tasked with trying to figure out how/why this leak happened and how we can prevent it from happening again.
This is a web-based application with Java Applets. Unix Sun Solaris 2.6 back-end with 8.1.5 database. We also have a Checkpoint firewall between the backend and the front end but I doubt that has anything to do with it.
Thanks for your interest,
Cherie
Jared.Still_at_ra
disys.com To: ORACLE-L_at_fatcity.com
cc: Cherie_Machler_at_gelco.com
01/02/02 03:35 Subject: Re: Shared pool wait
for library cache pin
PM
Cherie,
What constitutes 'a lot of shared pool waits (for libary cache pin)'?
Does it represent a significant percentage of total waits, or is it just crossing some predetermined threshold?
Is it causing a performance problem?
( as seen by users, not by a monitoring tool )
Jared
Cherie_Machler
@gelco.com To: Multiple recipients of
list ORACLE-L <ORACLE-L_at_fatcity.com>
Sent by: cc:
root_at_fatcity.c Subject: Shared pool wait for
library cache pin
om
01/02/02 12:20
PM
Please respond
to ORACLE-L
We are seeing a lot of shared pool waits (for libary cache pin) on our 8.1.5 web-based application. We are seeing this via Precise/Indepth SQL monitoring tool.
I haven't been able to find much documentation on shared pool waits or library cache pins.
Can anyone tell me what might be causing this problem?
Thanks,
Cherie
-- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: INET: Cherie_Machler_at_gelco.com Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051 San Diego, California -- Public Internet access / Mailing Lists -------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-LReceived on Thu Jan 03 2002 - 12:12:15 CST
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