[FLINK-5174] Fix memory leak in the CEP library.

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Duplicate
• Affects Version/s: 1.1.3
• Component/s: Library / CEP
• Assignee: Kostas Kloudas
• Reporter: Kostas Kloudas
• Created: 28/Nov/16 10:41
• Updated: 18/Mar/17 19:04
• Resolved: 18/Mar/17 19:04

Description

Currently the CEP library stores all the keys it has seen so far, so that when the time comes, it can iterate over all the stored NFAs and update them accordingly.

This implies that the state is never cleaned up and it can lead to memory issues.

To improve this, we could register timers for each new element and for the specific key, so that 1) only the relevant NFAs are fetched, and 2) the timers will be gc'ed upon firing.