Re: DX Lock problem

On Jun 28, 10:48 pm, sorc...@xxxxxxxxx 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 9.2.0.8 (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

.

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