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https://issues.apache.org/jira/browse/IGNITE-15962?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Alexey Kukushkin updated IGNITE-15962:
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Summary: CacheEntryRemovedListener makes the PUT operation to create ENTRY
CREATED events (was: CacheEntryRemovedListener makes the PUT operation to send
ENTRY CREATED events)
> CacheEntryRemovedListener makes the PUT operation to create ENTRY CREATED
> events
> --------------------------------------------------------------------------------
>
> Key: IGNITE-15962
> URL: https://issues.apache.org/jira/browse/IGNITE-15962
> Project: Ignite
> Issue Type: Improvement
> Affects Versions: 2.11
> Reporter: Alexey Kukushkin
> Priority: Major
> Attachments: CacheContinuousQueryEntry-HeapDump.png,
> CacheContinuousQueryEntry-StackTrace.png, EventListenerHeapUsage.java,
> IgniteServer.java, build.gradle
>
>
> {{CacheEntryRemovedListener}} configured withÂ
> {{MutableCacheEntryListenerConfiguration.isOldValueRequired = false}} makes
> the {{Cache#put}} operation to send {{CREATED}} events attached to the
> "Update" message. This is inefficient when working with large objects: our
> application running with limited heap memory fails with
> {{java.lang.OutOfMemoryError: Java heap space}} after executing a {{PUT}}
> operation since the entry referencing the object is "stuck" on the heap.
> h2. Reproducer
> h3. Steps
> We need two Ignite server nodes to demonstrate the problem. A cache is
> deployed on both the nodes and both the nodes listen to the {{ENTRY REMOVED}}
> events. Both the nodes disable fetching the {{CacheEntryEvent#getOldValue}}
> by setting {{MutableCacheEntryListenerConfiguration.isOldValueRequired =
> false}}
> # Build and run the attached [^IgniteServer.java]. This server is configured
> like described above and runs until manually terminated.
> # Build the run the attached test [^EventListenerHeapUsage.java] . This test:
> ## Starts another server configured like described above
> ## Puts a large object taking 35% of the free memory. This is done in an
> isolated scope so the memory after the operation is garbage collected,
> ## Attempts to allocate 70% of the heap.
> h3. Expected
> The last "allocate 70% of the heap" operation should succeed.
> h3. Actual
> {noformat}
> Caused by: java.lang.OutOfMemoryError: Java heap space
> at
> apache.ignite.issues.EventListenerHeapUsage.entryRemovedEventListenerFetchesValueOnHeap(EventListenerHeapUsage.java:33)
> {noformat}
> h2 Analysis
> For some reason configuring the event listener makes the {{IgniteCache#put}}
> operation to create and attach an instance of {{CacheContinuousQueryEntry}}
> with {{evtType=CREATED}} and {{newObject}} referencing the entry.
> The attached heap dump !CacheContinuousQueryEntry-HeapDump.png! collected on
> the {{OutOfMemoryError}} demonstrates the large object "stuck" on the heap.
> The attached {{CacheContinuousQueryEntry}} initialization
> !CacheContinuousQueryEntry-StackTrace.png! proves the {{ENTRY CREATED}}
> event is being created even though we did not configure it.
> It seems wrong that Ignite needs to attached the {{ENTRY CREATED}} event to
> the "update" message. Please enhance Ignite to not be doing that or explain
> why Ignite must do that.
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