RE: oracle database performance/availability/outage issue

  • From: "Kerber, Andrew" <Andrew.Kerber@xxxxxxx>
  • To: junk4trash@xxxxxxxxx, oracle-l@xxxxxxxxxxxxx
  • Date: Wed, 7 Feb 2007 10:17:06 -0600

Sounds like you need to increase the number of available latches.  Arent
there some init.ora settings for that?


Andrew W. Kerber 
Oracle DBA 


"If at first you dont succeed, dont take up skydiving" 

-----Original Message-----
From: oracle-l-bounce@xxxxxxxxxxxxx
[mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Alex zeng
Sent: Wednesday, February 07, 2007 10:12 AM
To: oracle-l@xxxxxxxxxxxxx
Subject: oracle database performance/availability/outage issue


If you have such experience or insight to the issue, please kindly
provide your help.



DB: 8.1.6

OS: HP-UX 11.00 

Hardware: PA-RISK, 8 cpu/16G memory



1.     DB operation on data dictionary (such as create table) is hung.
All are hung at 'latch free' events. The latch name is 'dml lock

2.     # of DB processes will climbing up till maximum connections
(150); then the database is unavailable to all new connections 

3.     Before # of DB processes overflow, some DB light operations on
user table are not affected, but not all. Huge operations (such as
backend job) on user tables are hung too because it might trigger data
dictionary operation. 


What actions have been taken, are being taken or need to be taken 

1.     Disabled large jobs such - in vain 

2.     Restarted database - in vain. This helps little. After times
passes, the number of processes will climb up and database goes down
again eventually. 

3.     Upper processes limit to 250 in database - GDBA is helping to
make the parameter change right now and the database will restart soon.
But I don't think this can resolve the issue. It only delays the outage.

4.     Logged TAR to metalink - 8.1.6 is out of support scope now. The
possibility to get support form Oracle Corp is low. 

5.     Further investigation needs to be taken upon the "data
dictionary" hung/latch free event. This is where we need your suggestion
and help. 



--The mount is there. 

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