The RetryEx in LockingTransaction should be static

Question

We are using clojure.data.json, and we profiled our project with jprofiler, it shows that there is a hotspot in LockingTransaction.Too many RetryEx instances were created during the profiling.
The retryex instance variable should be static as a class variable to avoid creating when a new STM transaction begins.

!profile.png!

The attacments are the profile result screen snapshot and the patch to make the retryex to be static.
I don't do any benchmark right now,but maybe a clojure.data.json performance benchmark will approve the patch works better.

Answer 1

Comment made by: alexmiller

I think the suggestion here is sound, but I have a hard time believing it will make much of a difference. My real question is why pprint is using dosync.

Answer 2

Comment made by: killme2008

I found it uses many dosync in writer as below:

https://github.com/clojure/clojure/blob/master/src/clj/clojure/pprint/pretty_writer.clj

It seems that using the dosync to change some mutable states.Maybe they can be rewrote into other forms such as atom,java object/lock etc.
But it's another story.

Answer 3

Reference: https://clojure.atlassian.net/browse/CLJ-1798 (reported by killme2008)