Memory leak in ConnectorTracker when push is enabled and no transmission from the client

[vaadin-bot]

Originally by arek_da

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In such scenario the syncIdToUnregisteredConnectorIds TreeMap gets overloaded causing eventually OutOfMemory error.
Please note that ConnectorTracker.cleanConcurrentlyRemovedConnectorIds is called upon transmission from the client.
In my case the application does huge amount of pushes while some clients use it as a display board (without any client interaction for a long time)

A fragment of heap trace:
759 715 240 (96,4%) [768] 68 com/fxe/gui/MainUI 0x78091e4d0
|- 758 225 000 (96,21%) [88] 7 com/vaadin/ui/ConnectorTracker 0x780af6898
|- 756 101 384 (95,94%) [80] 1 java/util/TreeMap 0x780b06690
|- 756 101 304 (95,94%) [56] 4 java/util/TreeMap$Entry 0x78ac358c8

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Imported from https://dev.vaadin.com/ issue #20048

[markathomas]

+1 - I have heap dumps where the connector tracker is holding hundreds of thousands of references for a small app. There definitely seems to be a memory leak in this area of Vaadin. I'll be happy to share an HPROF heap dump with the Vaadin team if they feel it would be helpful.

[Artur-]

Is this the same as #7657, which was fixed in 7.7.0?

[markathomas]

No, I am using 7.7.5 and seeing a memory leak in ConnectorTracker.

[markathomas]

No, I am using 7.7.5 and seeing a memory leak in ConnectorTracker.

[Artur-]

You do not happen to have an example project to share? If the problem is that syncIdToUnregisteredConnectorIds grows, then you are probably removing components in the push messages. Possibly a workaround could be to update components instead of adding and removing

The fix in #7657 should resolve it by acknowledging push messages when a component has been removed, giving the server a chance to do cleanup

[markathomas]

no, i don't have a simple example to share. shouldn't the fix for #7657 already be in the version i'm using, 7.7.5, or do i need to set a poll interval? we have opened a support request on this issue as we're having to drop containers every 2 days or so. Tatu is handling the support request and has access to our code and heap dump.

[TatuLund]

Related: #8111

[pleku]

Closed by 62c0d73