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  1. MariaDB Server
  2. MDEV-21068

Test MRR scans over partitioned tables

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    Details

    • Type: Task
    • Status: Closed (View Workflow)
    • Priority: Major
    • Resolution: Fixed
    • Fix Version/s: 10.3.23
    • Component/s: Tests
    • Labels:
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      Description

      This patch https://github.com/mariadb/server/commit/8eeb689e9fc57afe19a8dbff354b5f9f167867a9
      has added MRR support to partitioning engine. If the partitions ' table engine supports MRR, the ha_partition engine will also support it.

      The patch was targeting only the Spider engine, but actually it enabled MRR for partitioned DS-MRR engines (InnoDB,MyISAM and Aria). MRR support in MyRocks is not in MariaDB yet, but it in the upstream MyRocks so we will get in the next merge.

      MDEV-20611 fixes the basic issues with partitioned DS-MRR. It would be nice to have more test coverage.

      The test should have:

      • A partitioned table that supports [DS-]MRR. Nice to try different partitioning schemes.
      • The table must have an index.
      • The query must use MRR or BKA+MRR to read the data from the partitioned table.
      • AFAIU, there are two different cases:
        • The lookup tuples do not cover all partitioning fields. In this case, for each lookup tuple, ha_partition needs to search for it in all partitions (well, in all partitions that were left after partition pruning)
        • The lookup tuples cover partitioned fields. In this case, ha_partition will split the list of ranges into sub-lists that cover individual partitions.

      Things to cover:

      • non-trivial pushed Index Condition
      • Not-exists optimization (Use LEFT JOIN with WHERE inner_table.not_null_col IS NULL
      • BKAH (hashed BKA).

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              Assignee:
              Roel Roel Van de Paar
              Reporter:
              psergey Sergei Petrunia
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