Uploaded image for project: 'MariaDB Server'
  1. MariaDB Server
  2. MDEV-26939

support descending indexes for simple ORDER BY

Details

    Description

      in cases like

      CREATE TABLE t1 (a INT, b INT, INDEX (a DESC, b ASC));
      		 
      ...
      		 
      SELECT * FROM t1 ORDER BY a DESC, b ASC;

      In other cases descending indexes could be treated as disabled.

      Attachments

        Issue Links

          is part of

          Task - A task that needs to be done. MDEV-13756 Implement descending index: KEY (a DESC, b ASC)

          • Blocker - Blocks development and/or testing work, production could not run.
          • Closed
          relates to

          Task - A task that needs to be done. MDEV-26996 Support descending indexes in the range optimizer

          • Major - Major loss of function.
          • Closed

          Activity

            serg Sergei Golubchik added a comment -

            ORDER BY seems to be working already:

            sql/sql_select.cc

            		 
            23449
            		 
                const ORDER::enum_order keypart_order= 
            23450
            		 
                  (key_part->key_part_flag & HA_REVERSE_SORT) ? 
            23451
            		 
                  ORDER::ORDER_DESC : ORDER::ORDER_ASC;
            		 
            23452
            		 
                /* set flag to 1 if we can use read-next on key, else to -1 */
            		 
            23453
            		 
                flag= (order->direction == keypart_order) ? 1 : -1;

            serg Sergei Golubchik added a comment - ORDER BY seems to be working already: sql/sql_select.cc 23449 const ORDER::enum_order keypart_order= 23450 (key_part->key_part_flag & HA_REVERSE_SORT) ? 23451 ORDER::ORDER_DESC : ORDER::ORDER_ASC; 23452 /* set flag to 1 if we can use read-next on key, else to -1 */ 23453 flag= (order->direction == keypart_order) ? 1 : -1;

            People

              serg Sergei Golubchik
              serg Sergei Golubchik
              Votes:
              0 Vote for this issue
              Watchers:
              5 Start watching this issue

              Dates

                Created:
                Updated:
                Resolved:

                Git Integration

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