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Re: DX Lock problem

From: <>
Date: Fri, 29 Jun 2007 21:22:14 -0700
Message-ID: <>

On Jun 28, 10:48 pm, wrote:
> Hello folks,
> does anybody know the meaning of the v$lock.id1 column for a lock of
> type 'DX'?
> We are facing some problems w/ this type of lock.
> Sometimes a session hangs after acquiring a DX lock in exclusive mode
> serializing
> other sessions, any queries againts views related to distributed tx
> ([g]v$global_transaction,
> dba_pending_transactions, ...) hang there forever.
> Killing the session holding the lock doesn't help cause the lock is
> acquired with the same mode
> by another session. The only solution so far has been to shut the
> instance.
> I am trying to replicate the problem in our development environment
> using a couple of
> application witten in Pro*c but even if during some dml operation I
> can see a DX exclsuive
> lock, I havent't been able so far to stall the instance :(.
> If you guys know what excatly means that column, or better if you know
> what Oracle do
> during an distributed (xa) transaction would be greatly valuable for
> my debug activity.
> The production env wher i get the error is:
> 9iEE (2 nodes RAC)
> Solaris 9 64
> Bea Web Logic Server 8.1.4 (TM)
> Thanks
> g

10g v$lock_types says ID1 of DX lock is "transaction entry #". It's probably the slot number in the "distributed transaction table". This concept exists in 8i and probably still does in later versions, although its size is no longer controlled by distributed_transactions. I think this "table" is just a subset of the database transaction table. In 8i, ID1 usually goes down from the highest (set by distributed_transactions). In 9i, it seems to be random.

If you can't query (g)v$global_transaction and other related views, can you query their underlined tables? x$k2gte and pending_trans$, etc. How about SQL trace the session selecting from these tables? If you truss the shadow process, where does it hang?

Yong Huang Received on Fri Jun 29 2007 - 23:22:14 CDT

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