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Re: DX Lock problem

From: <sorcius_at_gmail.com>
Date: Fri, 29 Jun 2007 10:25:35 -0700
Message-ID: <1183137935.090186.204620@k29g2000hsd.googlegroups.com>


On Jun 29, 4:55 pm, Charles Hooper <hooperc2..._at_yahoo.com> wrote:
> On Jun 29, 6:37 am, sorc..._at_gmail.com wrote:
>
>
>
> > On Jun 28, 6:13 pm, Charles Hooper <hooperc2..._at_yahoo.com> wrote:
> > > On Jun 28, 10:48 am, sorc..._at_gmail.com wrote:
>
> > > Google search:
> > > oracle dx lock
> > > or
> > > oracle dx lock commit rollback
>
> > > Finds this page:
> > > http://www.jlcomp.demon.co.uk/faq/find_dist.html
>
> > > Charles Hooper
> > > IT Manager/Oracle DBA
> > > K&M Machine-Fabricating, Inc.
>
> > Charles,
>
> > that was clear to me... what is not clear is that I
> > can't see the point of acquiring an exclusive lock on an
> > object (whatever the object is, I smell it might be an
> > undo segment) in exclusive mode and serializing all other
> > session.
> > The symptom is evident in production: once in a while we see
> > this exclusive mode lock of type DX, the database slows down
> > and every single query (select i mean) not necessarly issued
> > from an xa connection against, for example, the gv$global_transaction
> > is there forever.
> > I am pretty sure is a bug... but I need to reproduce it somehow.
>
> > Yes, the distributed_lock_timeout is exactly 9000, as Mladen
> > suggested me, but i can't even force commit or rollback of that
> > in doubt transaction because I can't select from dba_pending_trans.
>
> > g
>
> I will have to defer this question to someone who uses distributed
> transactions more frequently than I. I recall seeing similar DX locks
> when I experimented with queries in remote databases. Sessions would
> occasionally hang for no apparent reason. It seems like ghost
> sessions would also remain connected to the database, long after the
> calling session was terminated. At the time I located the above
> article that indicated a COMMIT or ROLLBACK was needed following a
> SELECT to clear the lock, and it seemed to make perfect sense.
>
> You might want to check the first two links on this search page:http://groups.google.com/groups?um=1&tab=wg&hl=en&q=oracle%20dx%20loc...
>
> Mladen, thanks for the parameter hint.
>
> Charles Hooper
> IT Manager/Oracle DBA
> K&M Machine-Fabricating, Inc.

Charles and Mladen,

thank you for you support. Unfortunately I am stuck in a middle where my last lavel support (before issueing a SR to Oracle) says it's Bea's fault. Bea says it's Oracle's fault.

I am afraid it is something related to undo segments but I wasn't able to reproduce the problem so far.

g Received on Fri Jun 29 2007 - 12:25:35 CDT

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