APAR status
Closed as program error.
Error description
If trace is enabled and there are multiple transaction errors on
connections at the same time, then there is the possibility of a
deadlock occurring.
.
The java stack trace for the threads involved in the deadlock
will look like this:
This output is from a formatted Windows user.dmp file
(ip)=77F82870 at ntdll.dll ZwWaitForSingleObject + 000B
unwinding (old_esp=3C32EC70 old_eip=77F82870)
parms_on_stack=( 00000EFC, 00000000, 00000000 )
(ip)=7C573B28 at KERNEL32.dll WaitForSingleObjectEx + 005A
unwinding (old_esp=3C32EC80 old_eip=7C573B28)
unwinding (new_ebp=00000001) at 7C573B3D
parms_on_stack=( 00000EFC, FFFFFFFF, 00000000 )
(ip)=7C573B50 at KERNEL32.dll WaitForSingleObject + 000F
unwinding (old_esp=3C32ECA8 old_eip=7C573B50)
parms_on_stack=( 00000EFC, FFFFFFFF )
(ip)=00262C46 at hpi.dll _sysMonitorWait + 00A7
unwinding (old_esp=3C32ECB4 old_eip=00262C46)
unwinding (new_ebp=00770000) at 00262CB6
(ip)=10081EDC at jvm.dll _lkMonitorEnter + 01FC
unwinding (old_esp=3C32ECC8 old_eip=10081EDC)
unwinding (new_ebp=109B5A40) at 10081F49
(cc)=282A0EAF at
com/ibm/ejs/j2c/poolmanager/PoolManager.toString
()Ljava/lang/String; MMI2JIT
(cc)=2829E823 at
com/ibm/ejs/j2c/poolmanager/PoolManager.toString
()Ljava/lang/String; MMI2JIT
unwinding (old_esp=3C32ECFC old_eip=2829E823)
old_mb=2472A270
unwinding (new_ebp=00000000) at 2829EA35
unwinding (new_ebp=3C32ED70) at 2829EB60
(cc)=25A36DE4 at com/ibm/ejs/ras/TraceEvent.convertParameters
(Ljava/lang/Object;)V
unwinding (old_esp=3C32ED54 old_eip=25A36DE4)
old_mb=220B1600
unwinding (new_ebp=105A7C18) at 25A3707B
(cc)=2EBCAF6B at
com/ibm/ejs/j2c/poolmanager/PoolManager.release
(Lcom/ibm/ws/j2c/MCWrapper;Ljava/lang/Object;)V
unwinding (old_esp=3C32ED94 old_eip=2EBCAF6B)
old_mb=24729B68
.
The key calls to look for in the java stack are
-- com/ibm/ejs/j2c/poolmanager/PoolManager.toString
-- com/ibm/ejs/ras/TraceEvent.convertParameters
-- com/ibm/ejs/j2c/poolmanager/PoolManager.release
.
Local fix
As it happens, the problem cannot occur unless debug tracing is
enabled in the com.ibm.ejs.j2c.poolmanager.PoolManager class.
So one workaround is to disable tracing for the WAS.j2c
component.
Alternatively, you could leave j2c tracing enabled, but
disable only the debug tracing in the Pool Manager class, by
adding the following to the Trace Specification AFTER the
j2c element in the tracespec:
com.ibm.ejs.j2c.poolmanager.PoolManager=debug=disabled
.
Due to an issue with the tracing infrastructure, the Component
style j2c tracespec should be used instead of the Group stylebu
j2c tracespec. The combination of the two parameters would
look like:
com.ibm.ejs.j2c.*=all=enabled:
com.ibm.ejs.j2c.poolmanager.PoolManager=debug=disabled
Problem summary
****************************************************************
* USERS AFFECTED: WebSphere Application Server users of *
* JDBC, JCA and JMS Connections. *
****************************************************************
* PROBLEM DESCRIPTION: If transaction errors occur on more *
* than one Connection at the same time *
* the connection pool can deadlock *
* while trying to print trace *
* information. *
****************************************************************
* RECOMMENDATION: *
****************************************************************
If trace is enabled for WAS.j2c and connection errors occur on
more than one sharable connection at the same time, we can get
a deadlock while printing the pool contents.
The error only occurs when trace is enabled and there are a
lot of transaction errors (i.e. timeouts).
Problem conclusion
Provider heavier lock around the error case for after
completion. This allows only one thread to reach the toString
method at a time.
Temporary fix Comments
APAR information |
APAR number |
PQ90889 |
Reported component name |
WAS BASE 5.0 |
Reported component ID |
5630A3600 |
Reported release |
00W |
Status |
CLOSED PER |
PE |
NoPE |
HIPER |
NoHIPER |
Special Attention |
NoSpecatt |
Submitted date |
2004-07-01 |
Closed date |
2004-07-27 |
Last modified date |
2004-09-14 |
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
Modules/Macros
Publications Referenced
Applicable component levels |
R003 PSY |
UP |
R00A PSY |
UP |
R00H PSY |
UP |
R00I PSY |
UP |
R00P PSY |
UP |
R00S PSY |
UP |
R00W PSY |
UP |
|