Troubleshooting WebLogic Server 12c - Oracle WebLogic Server 12c Advanced Administration - page 196

The important Java methods to observe are com.myapp.db.DBUtil.executeQuery()
and oracle.jdbc.driver.OraclePreparedStatement.execute() . The application
is probably executing some function in the database, and all the threads are waiting for the
response, piling up the requests. In this specific case, it is possible that the problem is coming
from a slow database or from a large query that is not using any indexes, or even from some
sort of database lock. The thread dump can point to the right direction and, in this scenario,
further investigation will be needed in the application code and the database.
The [STUCK] flag means the thread is processing a request for a longer
time than has been configured in the Max Stuck Thread Time field of the
Overload configuration page for a Managed Server. The default configured
time is 600s . In conjunction with the other parameters and Node
Manager, it is possible to configure the Managed Server to automatically
restart when a maximum number of stuck threads is reached. This
configuration was set in Chapter 2, High Availability with WebLogic
Clusters , and may be useful in some scenarios, but you may lose the
opportunity to troubleshoot if the Managed Server restarts automatically.
[ACTIVE] and [STANDBY] are status flags related to the self-tuning
thread pool and do not indicate if the thread is processing a request.
See also
F Enabling the JRockit Mission Control Flight Recorder
F Analyzing a heap dump
Enabling the JRockit Mission Control Flight
Recorder
Mission Control is a monitoring and troubleshooting application provided with Oracle JRockit.
Besides the Management Console covered in Chapter 5 , Monitoring WebLogic Server
12c , Oracle JRockit also provides an important feature called the Flight Recorder. The
Flight Recorder registers the JVM's metrics and events, garbage collection behavior, thread
contention, locking, and other information, according to the configuration template you use.
The default template has a very low overhead and can be used in production environments.
This recipe will enable the Flight Recorder to store a flight recorder file ( .jfr extension) for
the Managed Servers PROD_Server01 , PROD_Server02 , PROD_Server03 , and PROD_
Server04 with the default template configuration. The recording will be configured to store
the last 24 hours of events or the maximum of a 100 MB file.