Alpakka JMS Consumer memory leak

Question

Alpakka JMS Consumer memory leak

arcavire opened this issue 7 months ago · comments

arc commented 7 months ago

Versions used

Akka version: 2.6.18
Alpakka version: 4.0.0
Scala version: 2.13
IBM MQ AllClient version: 9.3.4.0

Expected Behavior

akka.stream.alpakka.jms.impl.JmsConsumerSession not accumulating in memory

Actual Behavior

akka.stream.alpakka.jms.impl.JmsConsumerSession are accumulating in memory because they are still referenced from jmsListener

Observations

At the begging the consumer sessions are added to a list (jmsSessions) in akka.stream.alpakka.jms.impl.JmsConnector#onSession. Additionally, it is referenced by anonymous jms.MessageListener created in akka.stream.alpakka.jms.impl.JmsTxSourceStageLogic.

Then I restart the MQ and akka.stream.alpakka.jms.impl.JmsConnector#handleRetriableException is called. That method cleans the list of the sessions, but they are still referenced from the listeners:

Then the MQ is back and new sessions are added to the list, but the old ones are still kept in memory and will never be garbage collected. The number of the sessions kept in memory grows with each connection lost with MQ.

Reproducible Test Case

Start an application with JmsConsumer.txSource that reads from MQ.
Restart the MQ.

arc commented 6 months ago

Thank you

Enno Runne · Answer 1 · Wed Nov 22 2023 16:20:42 GMT+0800 (China Standard Time)

Thank you for your analysis of this problem.

Enno Runne · Answer 2 · Thu Nov 30 2023 01:54:46 GMT+0800 (China Standard Time)

Fixed with

#3041

arc · Answer 3 · Wed Dec 06 2023 18:54:21 GMT+0800 (China Standard Time)

@ennru, would it be possible to backport the fix to 4.0? This is the last version with Apache 2.0 license.