QOTD: Weblogic threads ~ Java EE Support Patterns

This is the first post of a new series that will bring you frequent and short “question of the day” articles. This new format will complement my existing writing and is designed to provide you with fast answers for common problems and questions that I often get from work colleagues, IT clients and readers.

Each of these QOTD posts will be archived and you will have access to the entire list via a separate page. I also encourage you to post your feedback, recommendations along with your own complement answer for each question.

Now let’s get started with our first question of the day!

Question:

What is the difference between Oracle Weblogic thread states & attributes (Total, Standby, Active, idle, Hogging, Stuck)?

Answer:

Weblogic thread state can be a particularly confusing topic for Weblogic administrators and individuals starting to learn and monitor Weblogic threads. The thread monitoring section can be accessed for each managed server Managed server under the Monitoring > Threads tab.

As you can see, the thread monitoring tab provides a complete view of each Weblogic thread along with its state. Now let’s review each section and state so you can properly understand how to assess the health.

# Summary section

Execute Thread Total Count: This is the total number of threads “created” from the Weblogic self-tuning pool and visible from the JVM Thread Dump. This value correspond to the sum of: Active + Standby threads
Active Execute Threads: This is the number of threads “eligible” to process a request. When thread demand goes up, Weblogic will start promoting threads from Standby to Active state which will enable them to process future client requests
Standby Thread Count: This is the number of threads waiting to be marked “eligible” to process client requests. These threads are created and visible from the JVM Thread Dump but not available yet to process a client request
Hogging Thread Count: This is the number of threads taking much more time than the current execution time in average calculated by the Weblogic kernel
Execute Thread Idle Count: This is the number of Active threads currently “available” to process a client request

In the above snapshots, we have:

Total of 43 threads, 29 in Standby state and 14 in Active state
Out of the 14 Active threads, we have 1 Hogging thread and 7 Idle threads e.g. 7 threads “available” for request processing
Another way to see the situation: we have a total of 7 threads currently “processing” client request with 1 out of 7 in Hogging state (e.g. taking more time than current calculated average)

# Thread matrix

This matrix gives you a view of each thread along with its current state. There is one more state that you must also understand:

STUCK: A stuck thread is identified by Weblogic when it is taking more time than the configured stuck thread time (default is 600 seconds). When facing slowdown conditions, you will normally see Weblogic threads transitioning from the Hogging state followed by STUCK, depending how long these threads remain stuck executing their current request