RE: Application waiting for a user lock.
- From: "Chitale, Hemant K" <Hemant-K.Chitale@xxxxxx>
- To: "tim@xxxxxxxxx" <tim@xxxxxxxxx>
- Date: Tue, 17 Feb 2015 06:56:36 +0000
Maybe it is multiple sessions running (requesting/waiting) concurrently (e.g.
60 sessions with 60second wait requests).
Would the REQUEST result in CPU usage ?
Would a SLEEP call result in CPU usage ?
Hemant K Chitale
From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On
Behalf Of Tim Gorman
Sent: Tuesday, February 17, 2015 11:57 AM
To: oracle-l@xxxxxxxxxxxxx
Subject: Re: Application waiting for a user lock.
Mladen,
The REQUEST procedure in the DBMS_LOCK
package<http://docs.oracle.com/cd/E11882_01/appdev.112/e40758/d_lock.htm#ARPLS66779>
has a TIMEOUT parameter which by default is set to "indefinite", but can be
set to a specified number of seconds. It appears that the developer set it to
"60" from what you're showing here (i.e. 60 waits in 3,601 seconds).
Hope this helps...
-Tim
On 2/16/15 20:43, Mladen Gogala (Redacted sender
mgogala@xxxxxxxxx<mailto:mgogala@xxxxxxxxx> for DMARC) wrote:
The wait events look like this:
Event Waits Time (s) (ms) Time
----------------------------------------- ------------ ----------- ------ ------
PL/SQL lock timer 60 3,601 60012 52.0
CPU time 3,233 46.7
db file sequential read 97,875 75 1 1.1
control file sequential read 13,019 5 0 .1
log file parallel write 1,344 4 3
Obviously, the application is using DBMS_LOCK. Is there anything that can be
done to make it cheaper? Not only
is the whole thing horribly slow, it also devours vast amounts of CPU. I
cannot go into the source, it's a 3rd party
application and someone discovered the keyword "WRAPPED". I've been looking for
a hidden instance parameter
which would change the DBMS_LOCK behavior and make it cheaper. Any ideas?
--
Mladen Gogala
Oracle DBA
http://mgogala.freehostia.com
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