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  1. MariaDB Server
  2. MDEV-5123

Remove duplicated conditions pushed both to join_tab->select_cond and join_tab->cache_select->cond for blocked joins.

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    Details

    • Type: Task
    • Status: Closed (View Workflow)
    • Priority: Major
    • Resolution: Fixed
    • Fix Version/s: 10.0.5
    • Component/s: None
    • Labels:
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      Description

      If there is a condition that depends only on the second table in a blocked join,
      the following blocked join algorithms (BNL, BNLH) use this condition to pre-filter records from this table prior to joining the records.

      Currently the optimizer extracts such a single table condition independently from the generic condition pushdown. As a result the same condition may be evaluated up to two times more. This is a problem if the condition is expensive. It also makes it problematic to move the condition to an optimal partial join (see MDEV-83).

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              Assignee:
              timour Timour Katchaounov (Inactive)
              Reporter:
              timour Timour Katchaounov (Inactive)
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