investigating deadlocks - wait-for-graph

From: D'Hooge Freek <>
Date: Thu, 25 Nov 2010 17:56:55 +0100
Message-ID: <>


I have a rac database ( on Redhat linux 4.6), which reports daily 5 or 6 times a global enqueue deadlock detected.

For my investigations I'm trying to understand the wait-for-graph, but information seems to be limited.

Global Wait-For-Graph(WFG) at ddTS[0.1062] :

BLOCKED 0x1d4929550 5 wq 2 cvtops x1 [0x1c001b][0x19644],[TX] [4A000-0001-00000D8A] 0 
BLOCKER 0x1b81f25d0 5 wq 1 cvtops x8 [0x1c001b][0x19644],[TX] [B3000-0002-00000C60] 1 
BLOCKED 0x1d4ac8e00 5 wq 2 cvtops x1 [0x20028][0x48c3e],[TX] [B3000-0002-00000C60] 1 
BLOCKER 0x1d48ee550 5 wq 1 cvtops x8 [0x20028][0x48c3e],[TX] [4A000-0001-00000D8A] 0

If my information is correct, the last column is the rac node and the before last is the transaction id.

wq 1 is the grant queue and wq 2 is the convert queue.

But what is the second and third column (lock mode?) And what about the other fields?

Any pointers?

Kind regards,

Freek D'Hooge
Oracle Database Administrator
tel +32(0)3 451 23 82

Received on Thu Nov 25 2010 - 10:56:55 CST

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