Thread
Dump analysis is key tool for analyzing the Performance issues and
troubleshooting many Issues. Currently available tools like samurai
says about the state of the Thread , they does not give detailed view
of what a thread is doing.
In
most cases , they dont mention what was happening inside a Thread ,
whether they are critical or normal. Are there any optimization's
that can be performed on these.
ThreadLogic
is a Tool which provides options for performing the above.Thread
Logic Comes in a form of Jar File.We need to manually run the file
using “java -jar threadLogic.jar”
Once
the GUI is open , we can select a Thread Dump file to open. Once you
open a file the starting screen will be like
We can see all the Threads , threads which are waiting for Monitors, sleeping threads , locking threads e.t.c.
Once
we click on the Dump No.1 , we can see a Information about the Thread
Dump and also about the Threads information below like
The
main important one is the “Advisory level”.Once a thread dump is
parsed and threads details are populated, each of the thread is then
analyzed against matching advisories and tagged appropriately.
If
you click on the “Advisory map” link you can see
Which gives you various level of information.
Each
of the advisory has a health level indicating severity of the issue
found, pattern, name, keyword and related advice.
If
you click on the Threads with an health (consider Fatal ) , we can
see information regarding the thread like
Thread
Logic also gives an advice on how to handle that. The Advisory gets
trigged based on either call execution patterns that are found inside
the thread stack of by other conditions inside the Thread Dump
The
health levels (in descending of severity) are FATAL (meant for
Deadlocks, STUCK, Finalizer blocked etc), WARNING, WATCH (worth
watching), NORMAL and IGNORE.
Thread
Groups
The
threads are associated with thread groups based on the functionality
or thread names. We can see thread Groups like
As we can see this is a Weblogic Thread dump , there is a group which says “WLS Thread Groups” with 40 threads. Clicking on the Groups gives you more insight like
One
can see the thread groups are divided into two buckets - WLS and
non-WLS related threads. The JVM threads, LDAP and other unknown
custom threads go under the non-WLS bucket while all the WLS, Muxer,
ADF, Coherence, Oracle, SOA, JMS, Oracle Adapter threads are all
under the WLS bucket.
Using
Thread Logic We can get more Information on how Threads Especially In
Weblogic Work.
Happy
learning :-)
