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  1. HBase
  2. HBASE-9488

Improve performance for small scan

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    • Reviewed
    • Better perfomance for small scan (e.g. scan range is within one data block(64KB)) through setting 'small' attribute as true in Scan Object

    Description

      review board:
      https://reviews.apache.org/r/14059/

      Performance Improvement
      Test shows about 1.5~3X improvement for small scan where limit<=50 under cache hit ratio=100%.
      See more performance test result from the picture attachment

      Usage:
      Scan scan = new Scan(startRow,stopRow);
      scan.setSmall(true);
      ResultScanner scanner = table.getScanner(scan);

      Set the new 'small' attribute as true for scan object, others are the same

      Now, one scan operation would call 3 RPC at least:
      openScanner();
      next();
      closeScanner();

      I think we could reduce the RPC call to one for small scan to get better performance

      Also using pread is better than seek+read for small scan (For this point, see more on HBASE-7266)

      Implements such a small scan as the patch, and take the performance test as following:

      a.Environment´╝Ü
      patched on 0.94 version
      one regionserver;
      one client with 50 concurrent threads;
      KV size:50/100;
      100% LRU cache hit ratio;
      Random start row of scan

      b.Results:
      See the picture attachment

      Attachments

        1. hbase-9488-94-v3.patch
          24 kB
          Chunhui Shen
        2. HBASE-9488-trunk.patch
          37 kB
          Chunhui Shen
        3. HBASE-9488-trunkV2.patch
          38 kB
          Chunhui Shen
        4. HBASE-9488-trunkV3.patch
          38 kB
          Chunhui Shen
        5. HBASE-9488-trunkV4.patch
          39 kB
          Michael Stack
        6. HBASE-9488-trunkV4.patch
          39 kB
          Chunhui Shen
        7. HBASE-9488-trunkV5.patch
          39 kB
          Chunhui Shen
        8. mergeRpcCallForScan.patch
          5 kB
          Chunhui Shen
        9. test results.jpg
          106 kB
          Chunhui Shen

        Activity

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            zjushch Chunhui Shen
            zjushch Chunhui Shen
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            Dates

              Created:
              Updated:
              Resolved: