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hpux question

navin
Super Advisor

hpux question

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
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8 REPLIES
madhuchakkaravarthy
Trusted Contributor

Re: hpux question

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
Patrick Wallek
Honored Contributor

Re: hpux question

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.

navin
Super Advisor

Re: hpux question

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

thanks
Learning ...
James R. Ferguson
Acclaimed Contributor

Re: hpux question

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...
Patrick Wallek
Honored Contributor

Re: hpux question

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.

Michael Steele_2
Honored Contributor

Re: hpux question

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?
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Kapil Jha
Honored Contributor

Re: hpux question

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+
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