Uploaded image for project: 'MariaDB ColumnStore'
  1. MariaDB ColumnStore
  2. MCOL-4559

Need to optimize common table expressions.

    XMLWordPrintable

Details

    • Task
    • Status: Open (View Workflow)
    • Major
    • Resolution: Unresolved
    • None
    • 23.10
    • None

    Description

      This is decidedly wrong. The CTE needs to be reused, not repeated.

      {{
      MariaDB [bts]> select calsettrace(1);
      ----------------

      calsettrace(1)

      ----------------

      0

      ----------------
      1 row in set (0.000 sec)

      MariaDB [bts]> explain
      -> with mn as
      -> (select count cnt, year from flights group by year)
      -> select * from
      -> (
      -> select * from mn
      -> union all
      -> select sum(cnt),'total' year from mn group by 'total'
      -> ) q;
      -----------------------------------------------------------------+

      id select_type table type possible_keys key key_len ref rows Extra

      -----------------------------------------------------------------+

      1 PUSHED SELECT NULL NULL NULL NULL NULL NULL NULL NULL

      -----------------------------------------------------------------+
      1 row in set (0.000 sec)

      MariaDB [bts]> with mn as
      -> (select count cnt, year from flights group by year)
      -> select * from
      -> (
      -> select * from mn
      -> union all
      -> select sum(cnt),'total' year from mn group by 'total'
      -> ) q;
      ---------------+

      cnt year

      ---------------+

      4624931 2020
      7856869 2018
      8092727 2019
      5819079 2015
      5617658 2016
      5674621 2017
      37685885 total

      ---------------+
      7 rows in set, 1 warning (0.623 sec)

      MariaDB [bts]> select calgettrace();
      ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

      calgettrace()

      ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

      Desc Mode Table TableOID ReferencedColumns PIO LIO PBE Elapsed Rows
      BPS PM flights 3028 (year) 0 9416 0 0.578 114
      TAS UM - - - - - - 0.561 6
      TNS UM - - - - - - 0.000 6
      TNS UM - - - - - - 0.000 6
      BPS PM flights 3028 (year) 0 9416 0 0.582 114
      TAS UM - - - - - - 0.562 6
      TNS UM - - - - - - 0.000 6
      TAS UM - - - - - - 0.000 1
      TNS UM - - - - - - 0.000 1
      TUS UM - - - - - - 0.003 7
      TNS UM - - - - - - 0.000 7

      ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
      1 row in set (0.000 sec)
      }}

      Attachments

        Activity

          People

            drrtuy Roman
            gdorman Gregory Dorman (Inactive)
            Votes:
            0 Vote for this issue
            Watchers:
            1 Start watching this issue

            Dates

              Created:
              Updated:

              Git Integration

                Error rendering 'com.xiplink.jira.git.jira_git_plugin:git-issue-webpanel'. Please contact your Jira administrators.