We've observed what appears to be the stream manager not releasing memory properly or holding onto memory indefinitely on heron 0.14.4. The following image is the rss of the heron stream manager, the red vertical line represents the same topology deployed on 0.14.4 on the left of the red line and 0.14.1 on the right of the red line. We can see that on 0.14.4 the rss for the heron stream manager grows until it pushed the container above its allocated memory and then forcibly gets killed while the same topology running on 0.14.1 shows a fairly consistent memory usage.

I do not currently have a test case setup that demonstrates this behavior but will work on getting one setup. It appears to only happen on topologies that utilize acking and we have not seen this behavior on those that do not.