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  1. Jackrabbit Content Repository
  2. JCR-2892

Large fetch sizes have potentially deleterious effects on VM memory requirements when using Oracle

    Details

    • Type: Bug
    • Status: Closed
    • Priority: Major
    • Resolution: Fixed
    • Affects Version/s: 2.2.2
    • Fix Version/s: 2.2.10, 2.3.2
    • Component/s: jackrabbit-core, sql
    • Labels:
      None
    • Environment:
      Oracle 10g+

      Description

      Since Release 10g, Oracle JDBC drivers use the fetch size to allocate buffers for caching row data.
      cf. http://www.oracle.com/technetwork/database/enterprise-edition/memory.pdf

      r1060431 hard-codes the fetch size for all ResultSet-returning statements to 10,000. This value has significant, potentially deleterious, effects on the heap space required for even moderately-sized repositories. For example, the BUNDLE table (from 'oracle.ddl') has two columns – NODE_ID raw(16) and BUNDLE_DATA blob – which require 16 b and 4 kb of buffer space, respectively. This requires a buffer of more than 40 mb [(16+4096) * 10000 = 41120000].

      If the issue described in JCR-2832 is truly specific to PostgreSQL, I think its resolution should be moved to a PostgreSQL-specific ConnectionHelper subclass. Failing that, there should be a way to override this hard-coded value in OracleConnectionHelper.

        Attachments

        1. oracleFetchSize.patch
          2 kB
          Danilo Ghirardelli
        2. JCR-2892.patch
          6 kB
          Claus Köll

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              • Assignee:
                c_koell Claus Köll
                Reporter:
                celkins Christopher Elkins
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                Dates

                • Created:
                  Updated:
                  Resolved: