Cassandra
  1. Cassandra
  2. CASSANDRA-4310

Multiple independent Level Compactions in Parallel

    Details

      Description

      Problem: If you are inserting data into cassandra and level compaction cannot catchup, you will create lot of files in L0.

      Here is a solution which will help here and also increase the performance of level compaction.

      We can do many compactions in parallel for unrelated data.
      1) For no over lapping levels. Ex: when L0 stable is compacting with L1, we can do compactions in other levels like L2 and L3 if they are eligible.
      2) We can also do compactions with files in L1 which are not participating in L0 compactions.

      This is specially useful if you are using SSD and is not bottlenecked by IO.

      I am seeing this issue in my cluster. The compactions pending are more than 50k and the disk usage is not that much(I am using SSD).
      I am doing multithreaded to true and also not throttling the IO by putting the value as 0.

      1. 4310-v6.txt
        55 kB
        Yuki Morishita
      2. 4310-v5.txt
        54 kB
        Jonathan Ellis
      3. 4310-v3.txt
        33 kB
        Yuki Morishita
      4. 4310-v2.txt
        27 kB
        Yuki Morishita
      5. 4310.txt
        25 kB
        Yuki Morishita

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          People

          • Assignee:
            Yuki Morishita
            Reporter:
            sankalp kohli
            Reviewer:
            Jonathan Ellis
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            Dates

            • Created:
              Updated:
              Resolved:

              Development