How expensive are Java (Solr) thread dumps?

Question

As part of some ongoing maintenance, we have been taking regular thread dumps for all threads in the JVM at a one minute interval. (Eg curl http://localhost:8983/solr/admin/threaddump.jsp )

What are the performance / other negative impacts of continuing this practice indefinitely?

Answer 1

Generally, JVM thread dumps are cheap, low impacting, regardless of the applications. Jmap -histos on the other hand, can be very performance impacting. I work in maintance, we do a lot of thread dumps, never seen a direct crash caused by thread dumping.

The only problem with running dumps once a minute is too much information.

Are you appending the dump to a separate file? In my experience you have to look at dumps over time to catch things like transient lock contention.