Reference to response payload is kept in each thread [SWS-1070]

smaxi opened SWS-1070 and commented

Each thread of the application keeps reference to response payload. This reference is getting cleaned/reused when thread gets used again.
This behavior is abnormal, because keeping reference to payload causes OoM when number of threads is high and payloads are big. It is not question of sizing of jvm as permanent heap requirements are n*m where n is the max size of the pool and m is the biggest size of response of the application.

How to reproduce:

Consider a method that returns StreamSource.
@PayloadRoot(namespace = PULLACK_NAMESPACE_URI, localPart = "PullRequest") @ResponsePayload public StreamSource requestDataGetEvents(@RequestPayload XMLStreamReader reader) throws DurableStorageException{……
and ensure that reply is big enough, then memory footprint would look similar to:
!https://user-images.githubusercontent.com/50314851/57211152-88802380-6fdf-11e9-87d3-32419659a846.png!

The reference to memory is kept and thread goes back to pool after processing the reply to the client. This reference is replaced by new reference once thread gets reused.

Ideas about resolution: either output stream is not closed, either reference to payload is not cleaned correctly.

Workaround: manipulate streams directly in the application which is not the objective here.

Cleanup thread locals by putting interceptor when output is sent to client<= a dirty way to achieve the needed behavior.

This is a copy-paste of the closed issue reported in: https://github.com/spring-projects/spring-framework/issues/22895

Affects: 2.3.1, 2.4.5, 3.0.7

Start by reproducing the issue with a method returning StreamSource and a sufficiently large response, then observe memory while pooled threads process repeated replies. Investigate how the response output stream and payload reference are handled when a thread returns to the pool. Done means payload references are released or cleaned before reuse and memory no longer grows with pool size.