MamaSubscription java finalizer will never run

Alpert, Reed <reed.alpert@...>



MAMAJNI: MamaSubscription has unnecessary finalizer which impacts memory #94


MamaSubscription java class has a finalizer which won't be called until after destroy() is called since destroy deletes the global ref in jni back to the java object. But if destroy is called then calling finalizer does nothing as it detects that destroy has already been called. The downside is that for a sub churn app each MamaSub is put on the finalizer queue, which delays the GC of the object (finalizer thread typically runs with low priority).


Example is the pub/sub churn app (MamaPublisher does not have finalizer) I am running. The MamaPubs on the heap vary from count of 500 - 15k, depending on how recently GC has run. The MamaSubs vary count between 10k and 40k, never getting below 10k, even just after GC has run. A heap dump downs the MamaSubs being held by the finalizer thread.


I propose that the finalizer in MamaSub be removed, since it will never run, and impacts the free space.






Reed Alpert | Corporate & Investment Bank | Market Data Services | J.P. Morgan | 4 Metrotech Center, 23rd Floor, Brooklyn, NY 11245 | T: 718.242.5198  | M: 917.414.4613 | reed.alpert@...

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