dfs lock handle

From: helter skelter <helterskelter_at_gmail.com>
Date: Mon, 21 Jun 2010 15:51:25 +0200
Message-ID: <hvnqt9$1ql$1_at_mx1.internetia.pl>



Hi,

I've got strange problem with my db.
It happend two times lately - many DML session has hung on "TX-index contention" waiting for the session which is hanging on "DFS handle lock" - with no blocker of course. Then like an avalanche...in few minutes almost all DML were hanging on dfs lock handle or TX-index contention.
I tried flush buffer cache (it was working in similar problems which I had once) but it also hung on 'dfs lock handle'. When I kill session with dfs lock, another session start to wait on this event...
No errors in alert log (db&asm), no traces, but I have some info from oradebug:

[343]/0/344/50328/0x50f72138/28801/IGN_DMP/25/28/[771]/none
...
[604]/0/605/23753/0x4e19c618/26949/IGN/411/412/[771]/none

[645]/0/646/1033/0x4e1d33c0/27988/NLEAF/467/470/[1095]/none

[1095]/0/1096/1/0x4e42d490/23833/LEAF/468/469//645
[771]/0/772/246/0x4e27bcf0/26727/LEAF/26/27//343

I see that many sessions are waiting for [771] which isn't waiting for anything.

Found 44 objects waiting for <cnode/sid/sess_srno/proc_ptr/ospid/wait_event>

     <0/772/246/0x50c40598/26727/DFS lock handle> Open chains found:
Chain 1 : <cnode/sid/sess_srno/proc_ptr/ospid/wait_event> :

     <0/772/246/0x50c40598/26727/DFS lock handle>

  • <0/344/50328/0x50c73bd8/28801/enq: TX - index contention> ........ ........

but I can't see any traces for PID 26727. any ideas ?

rac database 10.2.0.4, asm&clusterware 11.2.0.1, rhel 5

cheers Received on Mon Jun 21 2010 - 08:51:25 CDT

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