Deadlock ITL Waits
- From: Stalin <stalinsk@xxxxxxxxx>
- To: oracle-l <oracle-l@xxxxxxxxxxxxx>
- Date: Wed, 20 Jul 2011 15:37:07 -0700
We have been seeing lots of deadlock errors lately in load testing
environments and they all have been due to enq: TX - allocate ITL entry. In
reviewing the statspack report for the periods of deadlock, i see that, log
file sync wait being the top consumer with a terrible wait time. That makes
to me think the deadlock, is just a symptom of high log file sync wait
times. Below is the snippet from statspack and looking at these numbers,
especially CPU not being heavily loaded, wondering if this could be a case
of storage issue. Sys Admins are checking the storage layer but thought
would check here get any opinions/feedback.
Top 5 Timed Events Avg
%Total
~~~~~~~~~~~~~~~~~~ wait
Call
Event Waits Time (s) (ms)
Time
----------------------------------------- ------------ ----------- ------
------
log file sync 1,400,773 4,357,902 3111
91.4
db file sequential read 457,568 334,834 732
7.0
db file parallel write 565,843 27,573 49
.6
read by other session 16,168 7,395 457
.2
enq: TX - allocate ITL entry 575 6,854 11919
.1
-------------------------------------------------------------
Host CPU (CPUs: 64 Cores: 8 Sockets: 1)
~~~~~~~~ Load Average
Begin End User System Idle WIO
WCPU
------- ------- ------- ------- ------- -------
--------
3.13 7.04 2.26 3.30 94.44 0.00 7.81
Statistic Total per Second per
Trans
--------------------------------- ------------------ --------------
------------
redo synch time 435,852,302 120,969.3
309.7
redo synch writes 1,400,807 388.8
1.0
redo wastage 5,128,804 1,423.5
3.6
redo write time 357,414 99.2
0.3
redo writes 9,935 2.8
0.0
user commits 1,400,619 388.7
1.0
Environment : 11gr2 EE (11.2.0.1), Sol 10 Sparc
Thanks,
Stalin
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