MariaDB [rt3]> explain extended SELECT DISTINCT main.* FROM Tickets main CROSS JOIN Users Users_3 JOIN Groups Groups_1  ON ( Groups_1.Domain = 'RT::Ticket-Role' ) AND ( Groups_1.Type = 'Requestor' ) AND ( Groups_1.Instance = main.id ) LEFT JOIN CachedGroupMembers CachedGroupMembers_2  ON ( CachedGroupMembers_2.MemberI d = Users_3.id ) AND ( CachedGroupMembers_2.GroupId = Groups_1.id )  WHERE (Users_3.Name = 'IT-System') AND (main.Status != 'deleted') AND ( ( main.Owner = '2281908' OR  ( CachedGroupMembers_2.id IS NOT NULL )  )  AND  ( main.Status = 'new' OR main.Status = 'open' ) ) AND (main.Type = 'ticket') AND (main.EffectiveId =  main.id)  ORDER BY main.LastUpdated DESC  LIMIT 50;
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| id   | select_type | table                | type  | possible_keys                                                                       | key              | key_len | ref                     | rows | filtered | Extra                              |
+------+-------------+----------------------+-------+-------------------------------------------------------------------------------------+------------------+---------+-------------------------+------+----------+------------------------------------+
|    1 | SIMPLE      | Users_3              | const | Users1                                                                              | Users1           | 202     | const                   |    1 |   100.00 | Using index; Using temporary       |
|    1 | SIMPLE      | main                 | index | PRIMARY,Tickets2,Tickets6,created,apid_status,apid_owner,apid_type,apid_effectiveid | apid_lastupdated | 6       | NULL                    | 2641 |   100.00 | Using where                        |
|    1 | SIMPLE      | Groups_1             | ref   | Groups1,Groups2                                                                     | Groups1          | 139     | const,rt3.main.id,const |    1 |   100.00 | Using where; Using index; Distinct |
|    1 | SIMPLE      | CachedGroupMembers_2 | ref   | DisGrouMem,main,SHREDDER_CGM1                                                       | DisGrouMem       | 10      | rt3.Groups_1.id,const   |    1 |   100.00 | Using where; Using index; Distinct |
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