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  1. MariaDB Server
  2. MDEV-27420

Spider tables retain DESC attribute on indexes even though it has no meaning

Details

    Description

      Upon creation of Spider tables, indexes are accepted and stored with the table definition. Now with the addition of the DESC attribute, it is accepted and stored as well.

      The redundancy isn't new – the indexes themselves apparently aren't used in any way, and why they are retained in the table definition is in itself questionable. But it's legacy now. For the DESC attribute however, the general tendency seems to be to only keep it when it has real effect, so maybe it shouldn't be there.

      --source include/have_innodb.inc
      		 
       
      		 
      install soname 'ha_spider';
      		 
      set spider_same_server_link= on;
      		 
       
      		 
      eval create server s foreign data wrapper mysql options 
      (host '127.0.0.1', database 'test', user 'root', port $MASTER_MYPORT);
      		 
       
      		 
      create or replace table t (id int primary key) engine=InnoDB;
      		 
      create or replace table t_sp (id int, key(id desc)) engine=Spider COMMENT='wrapper "mysql", srv "s", table "t"';
      		 
       
      		 
      select * from t_sp;
      		 
      show create table t_sp;

      preview-10.8-MDEV-13756-desc-indexes 43444ff5

      		 
      show create table t_sp;
      		 
      Table	Create Table
      		 
      t_sp	CREATE TABLE `t_sp` (
      		 
        `id` int(11) DEFAULT NULL,
      		 
        KEY `id` (`id` DESC)
      		 
      ) ENGINE=SPIDER DEFAULT CHARSET=latin1 COMMENT='wrapper "mysql", srv "s", table "t"'

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        Issue Links

          is caused by

          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

          Bug - A problem which impairs or prevents the functions of the product. MDEV-27590 Auto-increment on Spider tables with DESC PK does not work properly

          • Critical - Crashes, loss of data, severe memory leak.
          • Closed

          Activity

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            elenst Elena Stepanova created issue -
            elenst Elena Stepanova made changes -
            Field Original Value New Value
            elenst Elena Stepanova made changes -
            Description Upon creation of Spider tables, indexes are accepted and stored with the table definition. Now with the addition of the DESC attribute, it is accepted and stored as well.

            The redundancy isn't new -- the indexes themselves apparently aren't used in any way, and why they are retained in the table definition is in itself questionable. But it's legacy now. For the DESC attribute however, the general tendency seems to be to only keep it when it has real effect, so maybe they shouldn't be there.

            {code:sql}
            --source include/have_innodb.inc

            install soname 'ha_spider';
            set spider_same_server_link= on;

            eval create server s foreign data wrapper mysql options
            (host '127.0.0.1', database 'test', user 'root', port $MASTER_MYPORT);

            create or replace table t (id int primary key) engine=InnoDB;
            create or replace table t_sp (id int, key(id desc)) engine=Spider COMMENT='wrapper "mysql", srv "s", table "t"';

            select * from t_sp;
            show create table t_sp;
            {code}

            {code:sql|title=preview-10.8-MDEV-13756-desc-indexes 43444ff5}
            show create table t_sp;
            Table Create Table
            t_sp CREATE TABLE `t_sp` (
              `id` int(11) DEFAULT NULL,
              KEY `id` (`id` DESC)
            ) ENGINE=SPIDER DEFAULT CHARSET=latin1 COMMENT='wrapper "mysql", srv "s", table "t"'
            {code}             		Upon creation of Spider tables, indexes are accepted and stored with the table definition. Now with the addition of the DESC attribute, it is accepted and stored as well.

            The redundancy isn't new -- the indexes themselves apparently aren't used in any way, and why they are retained in the table definition is in itself questionable. But it's legacy now. For the DESC attribute however, the general tendency seems to be to only keep it when it has real effect, so maybe it shouldn't be there.

            {code:sql}
            --source include/have_innodb.inc

            install soname 'ha_spider';
            set spider_same_server_link= on;

            eval create server s foreign data wrapper mysql options
            (host '127.0.0.1', database 'test', user 'root', port $MASTER_MYPORT);

            create or replace table t (id int primary key) engine=InnoDB;
            create or replace table t_sp (id int, key(id desc)) engine=Spider COMMENT='wrapper "mysql", srv "s", table "t"';

            select * from t_sp;
            show create table t_sp;
            {code}

            {code:sql|title=preview-10.8-MDEV-13756-desc-indexes 43444ff5}
            show create table t_sp;
            Table Create Table
            t_sp CREATE TABLE `t_sp` (
              `id` int(11) DEFAULT NULL,
              KEY `id` (`id` DESC)
            ) ENGINE=SPIDER DEFAULT CHARSET=latin1 COMMENT='wrapper "mysql", srv "s", table "t"'
            {code}
            elenst Elena Stepanova added a comment -

            See also MDEV-27590 – one of these should be redundant, either DESC has no meaning for Spider as was initially assumed and thus should be ignored from the start, and then the problem in MDEV-27590 will not exist; or it does have a meaning, then MDEV-27420 is not a bug.

            elenst Elena Stepanova added a comment - See also MDEV-27590 – one of these should be redundant, either DESC has no meaning for Spider as was initially assumed and thus should be ignored from the start, and then the problem in MDEV-27590 will not exist; or it does have a meaning, then MDEV-27420 is not a bug.
            elenst Elena Stepanova made changes -
            serg Sergei Golubchik made changes -
            Fix Version/s N/A [ 14700 ]
            Fix Version/s 10.8 [ 26121 ]
            Resolution Not a Bug [ 6 ]
            Status Open [ 1 ] Closed [ 6 ]

            People

              serg Sergei Golubchik
              elenst Elena Stepanova
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                Updated:
                Resolved:

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