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  1. Flink
  2. FLINK-7873

Introduce CheckpointCacheManager for reading checkpoint data locally when performing failover

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    Details

    • Type: New Feature
    • Status: Closed
    • Priority: Major
    • Resolution: Duplicate
    • Affects Version/s: 1.3.2
    • Fix Version/s: None
    • Labels:
      None

      Description

      Why i introduce this:
      Current recover strategy will always read checkpoint data from remote FileStream (HDFS). This will cost a lot of bandwidth when the state is so big (e.g. 1T). What's worse, if this job performs recover again and again, it can eat up all network bandwidth and do a huge hurt to cluster. So, I proposed that we can cache the checkpoint data locally, and read checkpoint data from local cache as well as we can, we read the data from remote only if we fail locally. The advantage is that if a execution is assigned to the same TaskManager as before, it can save a lot of bandwith, and obtain a faster recover.

      Solution:
      TaskManager do the cache job and manage the cached data itself. It simple use a TTL-like method to manage cache entry's dispose, we dispose a entry if it wasn't be touched for a X time, once we touch a entry we reset the TTL for it. In this way, all jobs is done by TaskManager, it transparent to JobManager. The only problem is that we may dispose a entry that maybe useful, in this case, we have to read from remote data finally, but users can avoid this by set a proper TTL value according to checkpoint interval and other things.

      Can someone give me some advice? I would appreciate it very much~

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              • Assignee:
                sihuazhou Sihua Zhou
                Reporter:
                sihuazhou Sihua Zhou
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                  Updated:
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