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  1. Derby
  2. DERBY-3934

Improve performance of reading modified Clobs

    Details

    • Type: Improvement
    • Status: Closed
    • Priority: Major
    • Resolution: Fixed
    • Affects Version/s: 10.5.1.1
    • Fix Version/s: 10.5.1.1
    • Component/s: JDBC
    • Labels:
      None
    • Bug behavior facts:
      Performance

      Description

      The performance of reading modified Clobs is poor, which is demonstrated by running a test program selecting a 10 MB Clob and then getting the contents using getSubString:

      • unmodified Clob (StoreStreamClob) : ~1 300 ms
      • modified Clob (TemporaryClob): ~156 000 ms

      In this case, the Clob was modified by changing the first character.

      A number of subtasks will be created to handle the various issues, which will be related to both performance and code cleanup.
      For a brief overview, see http://www.nabble.com/Suggestion-for-improving-ClobUpdatableReader-and-related-code-to20308303.html

        Attachments

        1. derby-3934-6a-UTF8Reader_remove_method.diff
          1 kB
          Kristian Waagan
        2. derby-3934-5a-UTF8Reader_cleanup.diff
          8 kB
          Kristian Waagan
        3. derby-3934-4a-getinternalreader_cachedlength.diff
          12 kB
          Kristian Waagan
        4. derby-3934-3a-clobupdreader_utf8reader.stat
          0.3 kB
          Kristian Waagan
        5. derby-3934-3a-clobupdreader_utf8reader.diff
          30 kB
          Kristian Waagan
        6. derby-3934-2a-intclob_new_methods.diff
          4 kB
          Kristian Waagan
        7. derby-3934-1a-clob_replace_test.diff
          3 kB
          Kristian Waagan

          Activity

            People

            • Assignee:
              kristwaa Kristian Waagan
              Reporter:
              kristwaa Kristian Waagan
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              Dates

              • Created:
                Updated:
                Resolved: