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  1. MariaDB Server
  2. MDEV-6398

ANALYZE UPDATE does not populate r_rows

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    Details

    • Type: Bug
    • Status: Closed (View Workflow)
    • Priority: Major
    • Resolution: Fixed
    • Affects Version/s: N/A
    • Fix Version/s: 10.1.0
    • Component/s: None
    • Labels:

      Description

      In the example below, UPDATE modifies 4 rows, status confirms there were 5 reads, and r_filtered in the plan is 100%, but r_rows is NULL. It does not look right.

      MariaDB [test]> create table t1 (i int);
      Query OK, 0 rows affected (0.66 sec)
       
      MariaDB [test]> insert into t1 values (1),(2),(3),(4);
      Query OK, 4 rows affected (0.08 sec)
      Records: 4  Duplicates: 0  Warnings: 0

      MariaDB [test]> flush status;
      Query OK, 0 rows affected (0.00 sec)
       
      MariaDB [test]> analyze update t1 set i=8;
      +------+-------------+-------+------+---------------+------+---------+------+------+--------+----------+------------+-------+
      | id   | select_type | table | type | possible_keys | key  | key_len | ref  | rows | r_rows | filtered | r_filtered | Extra |
      +------+-------------+-------+------+---------------+------+---------+------+------+--------+----------+------------+-------+
      |    1 | SIMPLE      | t1    | ALL  | NULL          | NULL | NULL    | NULL |    4 |   NULL |   100.00 |     100.00 |       |
      +------+-------------+-------+------+---------------+------+---------+------+------+--------+----------+------------+-------+
      1 row in set (0.08 sec)

      MariaDB [test]> show status like 'Handler_read%';
      +--------------------------+-------+
      | Variable_name            | Value |
      +--------------------------+-------+
      | Handler_read_first       | 0     |
      | Handler_read_key         | 0     |
      | Handler_read_last        | 0     |
      | Handler_read_next        | 0     |
      | Handler_read_prev        | 0     |
      | Handler_read_rnd         | 0     |
      | Handler_read_rnd_deleted | 0     |
      | Handler_read_rnd_next    | 5     |
      +--------------------------+-------+
      8 rows in set (0.00 sec)

      Branch: 10.1
      commit 12d6f89b073351169e070355e8db363d0d649749
      Author: Sergei Petrunia <psergey@askmonty.org>
      Date:   Thu Jun 26 15:55:25 2014 +0400

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              Assignee:
              psergey Sergei Petrunia
              Reporter:
              elenst Elena Stepanova
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                Updated:
                Resolved: