[jira] [Created] (FLINK-1442) Archived Execution Graph consumes too much memory

["Stephan Ewen (JIRA)" <ji...@apache.org>]

Stephan Ewen created FLINK-1442:
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             Summary: Archived Execution Graph consumes too much memory
                 Key: FLINK-1442
                 URL: https://issues.apache.org/jira/browse/FLINK-1442
             Project: Flink
          Issue Type: Bug
          Components: JobManager
    Affects Versions: 0.9
            Reporter: Stephan Ewen


The JobManager archives the execution graphs, for analysis of jobs. The graphs may consume a lot of memory.

Especially the execution edges in all2all connection patterns are extremely many and add up in memory consumption.

The execution edges connect all parallel tasks. So for a all2all pattern between n and m tasks, there are n*m edges. For parallelism of multiple 100 tasks, this can easily reach 100k objects and more, each with a set of metadata.

I propose the following to solve that:

1.  Clear all execution edges from the graph (majority of the memory consumers) when it is given to the archiver.

2. Have the map/list of the archived graphs behind a soft reference, to it will be removed under memory pressure before the JVM crashes. That may remove graphs from the history early, but is much preferable to the JVM crashing, in which case the graph is lost as well...

3. Long term: The graph should be archived somewhere else. Somthing like the History server used by Hadoop and Hive would be a good idea.




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