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  1. Accumulo
  2. ACCUMULO-4112

Poor performance due to MinC start/stop updates are always hsync'd

    Details

    • Type: Bug
    • Status: Resolved
    • Priority: Critical
    • Resolution: Fixed
    • Affects Version/s: None
    • Fix Version/s: 1.7.2, 1.8.0
    • Component/s: tserver
    • Labels:
      None
    • Environment:

      Fluo testing on a 20-node cluster

      Description

      Keith Turner writes:

      I was running a Fluo test with 1.8.0-SNAP on my workstation. My Fluo table had a ton of tablets. I was seeing terrible performance. I started looking at the tserver and noticed it was always calling hsync. I tracked down the problem to the fact that when minc start and stop events are written to the log they are always written w/ sync level. My poor little tserver was constantly minor compacting (probably had around 600 tablets that were all being written to).

      I changed the test config to create like 15 tablets and the performance was much better. All cores were 100% utilized, which was not the case when hsync was always called.

        Attachments

        1. HSyncOverheadExperiment.png
          16 kB
          Eric Newton
        2. MinCFlushPerfTest.java
          4 kB
          Eric Newton
        3. Sync-Flush-Log-Performance.png
          30 kB
          Eric Newton

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              • Assignee:
                kturner Keith Turner
                Reporter:
                ecn Eric Newton
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