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  1. Lucene - Core
  2. LUCENE-4462

Publishing flushed segments is single threaded and too costly

    Details

    • Type: Improvement
    • Status: Closed
    • Priority: Major
    • Resolution: Fixed
    • Affects Version/s: 4.0-ALPHA, 4.0-BETA, 4.0
    • Fix Version/s: 4.1, 6.0
    • Component/s: core/index
    • Labels:
      None
    • Lucene Fields:
      New, Patch Available

      Description

      Spinoff from http://lucene.markmail.org/thread/4li6bbomru35qn7w

      The new TestBagOfPostings failed the build because it timed out after 2 hours ... but in digging I found that it was a starvation issue: the 4 threads were flushing segments much faster than the 1 thread could publish them.

      I think this is because publishing segments (DocumentsWriter.publishFlushedSegment) is actually rather costly (creates CFS file if necessary, writes .si, etc.).

      I committed a workaround for now, to prevent starvation (see svn diff -c 1394704 https://svn.apache.org/repos/asf/lucene/dev/trunk), but we really should address the root cause by moving these costly ops into flush() so that publishing is a low cost operation.

        Attachments

        1. LUCENE-4462.patch
          13 kB
          Simon Willnauer
        2. LUCENE-4462.patch
          13 kB
          Simon Willnauer

          Activity

            People

            • Assignee:
              simonw Simon Willnauer
              Reporter:
              mikemccand Michael McCandless
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              Dates

              • Created:
                Updated:
                Resolved: