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  1. MariaDB Server
  2. MDEV-4400

wrong numbers for SHOW INDEX and SHOW TABLE STATUS with EITS

        Details

        • Type: Bug
        • Status: Open
        • Priority: Minor
        • Resolution: Unresolved
        • Affects Version/s: 10.0.2
        • Fix Version/s: 10.0
        • Component/s: None
        • Labels:
          None
        • Environment:
          observed in the 10.0-mdev83 tree used for DBT3

          Description

          With EITS (use_stat_tables='preferably') and correct stats in mysql.table/index_stats the following statements return the InnoDB internal estimates instead of the exact numbers:

          • SHOW TABLE STATUS
          • SHOW INDEX FROM ...

          Example results for a table with 8000 rows:

          +----------+
| count(*) |
+----------+
|     8000 |
+----------+
+---------+---------+----------+----------+
| Table   | Op      | Msg_type | Msg_text |
+---------+---------+----------+----------+
| test.t1 | analyze | status   | OK       |
+---------+---------+----------+----------+
+---------+------------+-------------+
| db_name | table_name | cardinality |
+---------+------------+-------------+
| test    | t1         |        8000 |
+---------+------------+-------------+
+---------+------------+------------+--------------+---------------+
| db_name | table_name | index_name | prefix_arity | avg_frequency |
+---------+------------+------------+--------------+---------------+
| test    | t1         | PRIMARY    |            1 |        1.0000 |
| test    | t1         | c1         |            1 |        1.0000 |
| test    | t1         | c2         |            1 |       81.6327 |
+---------+------------+------------+--------------+---------------+
+----------------+
| c2 cardinality |
+----------------+
|        97.9999 |
+----------------+
+-------+----------+--------------+-------------+-------------+
| Table | Key_name | Seq_in_index | Column_name | Cardinality |
+-------+----------+--------------+-------------+-------------+
| t1    | PRIMARY  |            1 | c1          |        8050 |
| t1    | c1       |            1 | c1          |        8050 |
| t1    | c2       |            1 | c2          |         187 |
+-------+----------+--------------+-------------+-------------+
+------+--------+---------+------------+------+
| Name | Engine | Version | Row_format | Rows |
+------+--------+---------+------------+------+
| t1   | InnoDB |      10 | Compact    | 8050 |
+------+--------+---------+------------+------+

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                  • Assignee:
                    igor Igor Babaev
                    Reporter:
                    axel Axel Schwenke
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                    Dates

                    • Created:
                      Updated: