OAS report server sometimes does not create reports

  • From: Yong Huang <yong321@xxxxxxxxx>
  • To: oracle-l@xxxxxxxxxxxxx
  • Date: Tue, 4 Sep 2012 14:12:21 -0700 (PDT)

Oracle Application Server 10.1.0.3 on RHEL 4

Once in a while, users get error "REP-0178: Cannot connect to Reports Server 
..." when trying to create a report. Whenever this happens, I notice that the 
report server java process (found by ps -ef | grep rep_) shows ORA-4020 in 
strace output:

$ strace -f -s 85 -e trace=write -p 3692
Process 3713 attached with 14 threads - interrupt to quit
[ Process PID=3692 runs in 32 bit mode. ]
...
ORA-04020: deadlock detected while trying to lock object 
/Namespace0002/PKG_ACC_DATA
...

If it were from RDBMS, we would know it's a deadlock related to a library cache 
object, perhaps another or the current session is compiling it while this 
session tries to execute it. But this is from a report server, and PKG_ACC_DATA 
is a package in the report, not in the database (not in dba_objects). I have no 
solution to this problem and just kill the process. If the report server is 
managed by OPMN, a new report server process is immediately spawned and hung 
report requests are created (new files appear in reports cache directory). If 
not, I can manually start the report server with rwserver.sh and the problem is 
solved, temporarily.

Oracle support suggested increasing all kinds of capacity related params 
(cacheSize, initEngine,...), deleting .dat files, to no avail. I changed from 
in-process to standalone report server. The problem seems to occur less often. 
Any insight is appreciated.

Yong Huang
(Full strace output of the misbehaving report java process is shown at the 
bottom of http://yong321.freeshell.org/oranotes/ReportServer.txt )
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