Re: RAC internals - GLOBAL ENQUEUE SERVICES DEADLOCK DETECTED

<yong321_at_yahoo.com> wrote in message
news:1131135857.443704.31690_at_g47g2000cwa.googlegroups.com...
> Dusan Bolek wrote:
>> > Metalink Note:262226.1 offers some interpretation. Your process 131321
>> > on node 1 is waiting for a TX lock in mode 5 (the two hex numbers,
>> > 0x2b90011 and 0x5f20, may be id1 and id2 in v$lock, respectively).
>> > Process 131317 on the same node is holding it.
>>
> You're right. I did some testing and find that the two numbers,
> [131321,1285], in your case, do not in any way denote a process
> (Note:262226.1 says the first number is PID). Instead they correspond
> to transaction_id0 and transaction_id1 of v$ges_blocking_enqueue,
> respectively (or the same in v$dlm_locks). Documentation says they're
> lower and upper 4 bytes of the transaction identifier where the lock
> belongs to. I can't find more information about it. Perhaps for our
> purpose, we can conceptually think of the combination of the two
> numbers, i.e. a transaction identifier, as a process identifier.
>
> By the way, I do see the SQL involved in the global deadlock (tested in
> 9.2.0.7.0 on Linux):
> ...
> *** 2005-11-04 13:38:33.199
> user session for deadlock lock 0x7553ab14
> ...
> Current SQL Statement:
> update test set a = :"SYS_B_0" where a = :"SYS_B_1"
> Global Wait-For-Graph(WFG) at ddTS[0.28] :
> BLOCKED 0x7553ab14 5 [0xf001d][0x8353],[TX] [2162689,7995] 0
> ...
>
> In any case, follow Jonathan's practical advice.
>
> Yong Huang
>

Given that the documentation and notes are wrong about the process id / transaction id - might the comment about the mode 5 lock also be wrong ?

Could you see a transaction holding or requesting a TX mode 5 in the few seconds before the deadlock was reported ?

-- 
Regards

Jonathan Lewis

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