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  1. MariaDB Server
  2. MDEV-13756

Implement descending index: KEY (a DESC, b ASC)

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    Description

      MySQL 8.0 introduced support for descending indexes in WL#1074. This involved some changes in InnoDB and many in the optimizer.

      MariaDB and older versions of MySQL silently ignore the ASC/DESC attribute in KEY definitions. All index fields (KEY_PART) are sorted in ascending order.

      The Oracle database defines the NULLS FIRST and NULLS LAST attributes for the ORDER BY clause, but not for CREATE INDEX. The defaults are the exact opposite of InnoDB behaviour:

      NULLS LAST is the default for ascending order, and NULLS FIRST is the default for descending order.

      InnoDB in MariaDB and before MySQL 8.0 supports only ascending order, and it sorts NULLS FIRST, not NULLS LAST like the above quote suggests Oracle to do.

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            marko Marko Mäkelä created issue -
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            Field Original Value New Value
            NRE Projects RM_105_CANDIDATE
            julien.fritsch Julien Fritsch made changes -
            Assignee Ralf Gebhardt [ ralf.gebhardt@mariadb.com ]
            marko Marko Mäkelä made changes -
            ralf.gebhardt Ralf Gebhardt made changes -
            Labels Oracle SQL Compatibility Oracle SQL
            psergei Sergei Petrunia made changes -
            Labels Compatibility Oracle SQL Compatibility Oracle SQL optimizer-feature
            ralf.gebhardt Ralf Gebhardt made changes -
            Assignee Ralf Gebhardt [ ralf.gebhardt@mariadb.com ] Sergei Petrunia [ psergey ]
            serg Sergei Golubchik made changes -
            Assignee Sergei Petrunia [ psergey ] Marko Mäkelä [ marko ]
            serg Sergei Golubchik made changes -
            Fix Version/s 10.8 [ 26121 ]
            serg Sergei Golubchik made changes -
            Assignee Marko Mäkelä [ marko ] Sergei Petrunia [ psergey ]
            serg Sergei Golubchik made changes -
            Fix Version/s 10.8 [ 26121 ]
            serg Sergei Golubchik made changes -
            serg Sergei Golubchik made changes -
            serg Sergei Golubchik made changes -
            psergei Sergei Petrunia made changes -
            Fix Version/s 10.8 [ 26121 ]
            psergei Sergei Petrunia made changes -
            Status Open [ 1 ] In Progress [ 3 ]
            serg Sergei Golubchik made changes -
            Workflow MariaDB v3 [ 82489 ] MariaDB v4 [ 131820 ]
            elenst Elena Stepanova made changes -
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            Status In Progress [ 3 ] In Testing [ 10301 ]
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            Assignee Sergei Petrunia [ psergey ] Elena Stepanova [ elenst ]
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            marko Marko Mäkelä made changes -
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            serg Sergei Golubchik made changes -
            elenst Elena Stepanova made changes -
            serg Sergei Golubchik made changes -
            serg Sergei Golubchik made changes -
            Priority Major [ 3 ] Blocker [ 1 ]
            elenst Elena Stepanova made changes -
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            elenst Elena Stepanova made changes -
            elenst Elena Stepanova made changes -
            elenst Elena Stepanova made changes -
            elenst Elena Stepanova made changes -
            elenst Elena Stepanova made changes -
            elenst Elena Stepanova made changes -
            elenst Elena Stepanova made changes -
            elenst Elena Stepanova made changes -
            elenst Elena Stepanova made changes -
            elenst Elena Stepanova made changes -
            elenst Elena Stepanova made changes -
            Assignee Elena Stepanova [ elenst ] Sergei Golubchik [ serg ]
            Status In Testing [ 10301 ] Stalled [ 10000 ]
            serg Sergei Golubchik made changes -
            Fix Version/s 10.8.1 [ 26815 ]
            Fix Version/s 10.8 [ 26121 ]
            Resolution Fixed [ 1 ]
            Status Stalled [ 10000 ] Closed [ 6 ]
            elenst Elena Stepanova made changes -
            elenst Elena Stepanova made changes -
            elenst Elena Stepanova made changes -
            elenst Elena Stepanova made changes -
            danblack Daniel Black made changes -
            ralf.gebhardt Ralf Gebhardt made changes -
            Labels Compatibility Oracle SQL optimizer-feature Compatibility Oracle Preview_10.8 SQL optimizer-feature
            rob.schwyzer@mariadb.com Rob Schwyzer (Inactive) made changes -
            rob.schwyzer@mariadb.com Rob Schwyzer (Inactive) made changes -
            mariadb-jira-automation Jira Automation (IT) made changes -
            Zendesk Related Tickets 154697 162923
            marko Marko Mäkelä made changes -
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              serg Sergei Golubchik
              marko Marko Mäkelä
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                Updated:
                Resolved:

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