topic Re: hpux question in Operating System - HP-UX

hpux question

navin — Thu, 01 Apr 2010 17:16:22 GMT

hello all,

just to see if you have encountered this before -
on hpux box - oracle and app ruuning . users get performance issues and oracle log shows deadlocked detected..

any idea?
thanks

Re: hpux question

madhuchakkaravarthy — Thu, 01 Apr 2010 17:25:54 GMT

hi

deadlock on Oracle can occurs if multiple statements try to update/delete the same datas at the same time and are waiting for eachothers to resolve before unlocking the datas.

Check your queries or the jobs running at this time and see which ones are conflicting

regards

MC

Re: hpux question

Patrick Wallek — Thu, 01 Apr 2010 17:27:24 GMT

A deadlock is typically a database problem, not an operating system problem, hence the Oracle log showing the problem.

Your DBAs need to look and see what is happening in the database. There are likely 2, or more, that have each other locked.

Re: hpux question

Patrick Wallek — Thu, 01 Apr 2010 17:30:37 GMT

Have a look at the following links:

http://www.oracle-base.com/articles/misc/Deadlocks.php

http://www.dba-oracle.com/t_deadlock.htm

http://www.dbmotive.com/oracle_error_codes.php?errcode=00060

http://forums.oracle.com/forums/thread.jspa?threadID=598209

Re: hpux question

navin — Thu, 01 Apr 2010 17:38:09 GMT

thanks all for your reply and time -
is there a possibility less system resource(memory , swap) cause this deadock?

thanks

Re: hpux question

James R. Ferguson — Thu, 01 Apr 2010 17:46:56 GMT

Hi:

As Patrick notes, this is likely a database problem and then likely an application problem.

Deadlocks occur when two processes don't observed a predicate, canonical locking order.

For example, consider the case if two processes (#1 and #2) want to lock resources A and B. Imagine that the locking order should be (the canonical order) 'A' then 'B', but process-1 locks resource-B first. Process-2 can lock 'A' but cannot lock 'B' as process-1 holds the lock. Furthermore, process-1 can't get lock 'A' because process-2 has it. This is the deadlock.

Regards!

...JRF...

Re: hpux question

Patrick Wallek — Thu, 01 Apr 2010 17:47:28 GMT

Doubtful. If it is, it is indirectly.

A remote possibility would be that a lack of resources causing one process to run slow. If another process then runs that tries to access/update the EXACT same data, then you could have a deadlock.

Re: hpux question

Michael Steele_2 — Thu, 01 Apr 2010 17:50:41 GMT

There is supposed to be a db_deaklock utility run by the dba when this happens.

http://www.oracle.com/technology/documentation/berkeley-db/db/api_reference/C/db_deadlock.html

Deadlocks are a process error. The only processes in HP-UX are service daemons typically, certainly not the kind of memory or I/O or cpu resource hogs shown by application processes.

I mean, when was the last time you ever heard of an O/S memory leak? Never? Well, same for O/S deadlocks. If the GD O/S can't run, how do you expect the applications to run?

Re: hpux question

Kapil Jha — Sun, 04 Apr 2010 01:51:29 GMT

I suppose you need to as oracle team to check the traces (.trc) file, from there they could get some infomation why deadlock is happening, for sure its because the query you running is depending upon another query/table which is not availble to use for your query.

BR,
Kapil+