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  1. MariaDB Server
  2. MDEV-9168

altering a column comment does a full copy

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    • Sprint:
      10.0.25

      Description

      Altering column's comment does a full table copy. It should be executed by only changing the frm.

      initial issue description follow

      This is a new feature request and is similar to this request. http://bugs.mysql.com/bug.php?id=64439

      We have multiple mariadb instances managing ~2.5T of our data. We decided to document them using table/column comments. Unfortunately, there isnt an easier way of doing this.

      1) Filed a bug regarding altering table comment doing full copy. MDEV-9103
      2) Changing the column comment does the full copy (MDEV-9168)
      3) Also, current syntax is error prone since you need to re-declare the data type (MDEV-9878)

      It would be nice to have the below:
      ALTER TABLE 'myTable' ALTER COLUMN `myField` ADD COMMENT 'a comment'

      Instead of:
      ALTER TABLE `myTable` CHANGE `myField` `myField` varchar(20) NOT NULL COMMENT 'my comment'

      I agree that comments work great, if we have them created while creating the table. But, its almost impossible to update/add them at the later stage for the bigger tables in the production.

      Is there a better way of documenting the tables instead of using comments ? Please let me know.

      Thanks.

      -Bala

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              Assignee:
              serg Sergei Golubchik
              Reporter:
              bala.linux Bala
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