EntryProcessor Invocations Using More Memory in Coherence 3.7.1 Compared to Earlier Releases (Doc ID 1463402.1)

Symptoms

A Coherence cluster and the applications using is are being migrated from Coherence 3.5.3 to 3.7.1.3.  Some of the EntryProcessor operations the applications invoke are now encountering OutOfMemoryError exceptions which were not seen when using Coherence 3.5.3.

The application is processing the contents of two other caches, each of which contains 120 million entries and is combining the data to create a third cache, which is part of a different distributed service from the first two caches.

The application essentially invokes:

The EntryProcessor in the method iterates over the set passed to it by Coherence and extracts one field from each object and executes a second EntryProcessor which manipulates the objects in the third cache.  Since the two caches are part of different services the invocation of one EntryProcessor from the other is safe and does not introduce any chances of deadlock.

While doing this process the OutOfMemoryError exception is thrown.

Examining the heap reveals the following objects, only seen in the Coherence 3.7.1 heaps, consuming lots of memory:

Changes

Only change was the upgrade from Coherence 3.5.3 to 3.7.1.3.  No application changes had been made.

Cause

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