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  1. MariaDB Server
  2. MDEV-9999

Change the default value of optimizer_use_condition_selectivity

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    • Task
    • Status: Closed (View Workflow)
    • Major
    • Resolution: Duplicate
    • N/A
    • Optimizer
    • None

    Description

      Currently, the default for optimizer_use_condition_selectivity is 1

      https://mariadb.com/kb/en/mariadb/server-system-variables/#optimizer_use_condition_selectivity

      Meanings of values from here:

      1 Use selectivity of predicates as in MariaDB 5.5.
      		 
      2 Use selectivity of all range predicates supported by indexes.
      		 
      3 Use selectivity of all range predicates estimated without histogram.
      		 
      4 Use selectivity of all range predicates estimated with histogram.
      		 
      5 Additionally use selectivity of certain non-range predicates calculated on record sample.

      We could change the default to be 4. (This is not a big change as it may seem, because histograms are not collected automatically).

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          is duplicated by

          Task - A task that needs to be done. MDEV-15253 Default optimizer setting changes for MariaDB 10.4

          • Critical - Crashes, loss of data, severe memory leak.
          • Closed
          is part of

          Task - A task that needs to be done. MDEV-7635 update defaults and simplify mysqld config parameters

          • Blocker - Blocks development and/or testing work, production could not run.
          • Closed

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              varun Varun Gupta (Inactive)
              psergei Sergei Petrunia
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                Updated:
                Resolved:

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