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  1. EXASOL Roadmap
  2. EXASOL-2847

Improved compile time in some DML operations

    Details

    • Type: Improvement
    • Status: Resolved
    • Priority: Normal
    • Resolution: Fixed
    • Fix Version/s: Exasol 7.1.0
    • Component/s: None
    • Labels:
      None

      Description

      Background

      Exasol database automatically computes and stores column statistics on demand, e.g. when joining tables for the first time. Those statistics consist of distinct estimates, minimum & maximum values, balancing, and other information. They are used by our query optimizer for estimation of join costs, filter sensitivities, etc.

      The computation of column statistics is a compute-intensive operation. Therefore, they are maintained as part of DML statements. If a significant amount of data has been changed since the last computation a recalculation is triggered.

      Improvement

      DML compile time is improved if the following conditions are met:

      • A DML statement is executed
      • Data resides on HDD
      • Recalculation of column statistics is triggered

      This improvement can be identified by a reduced time in COMPILE/EXECUTE.

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            • Assignee:
              CaptainEXA Captain EXASOL
              Reporter:
              CaptainEXA Captain EXASOL
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              Dates

              • Created:
                Updated:
                Resolved: