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  1. MariaDB Server
  2. MDEV-25845

Remove one SELECT_DESCRIBE check in JOIN::optimize_inner()

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Details

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

    Description

      This is a followup to MDEV-25576, this part:

      https://jira.mariadb.org/browse/MDEV-25576?focusedCommentId=190651&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-190651

      JOIN::optimize_inner has this code

        if (const_table_map != found_const_table_map &&
      		 
            !(select_options & SELECT_DESCRIBE))
      		 
        {
      		 
          // There is at least one empty const table
      		 
          zero_result_cause= "no matching row in const table";
      		 
          ...
      		 
          goto setup_subq_exit;

      The !(select_options & SELECT_DESCRIBE)) part is bad practice.

      Removing it causes a lot of changes in EXPLAIN output.

      Attachments

        Issue Links

          duplicates

          Task - A task that needs to be done. MDEV-25846 Remove one SELECT_DESCRIBE check in JOIN::optimize_inner()

          • Major - Major loss of function.
          • Closed
          relates to

          Bug - A problem which impairs or prevents the functions of the product. MDEV-25576 The statement EXPLAIN running as regular statement and as prepared statement produces different results for UPDATE with subquery

          • Major - Major loss of function.
          • Closed

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              psergei Sergei Petrunia
              psergei Sergei Petrunia
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              Dates

                Created:
                Updated:

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