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  1. MariaDB Server
  2. MDEV-13076

AliSQL: [Feature] Issue#43 Add Column Dynamically

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      Description

      Description:
      ------------
      The original adding column will move the data. it will consume long time.
      Now the new row_format COMFORT for InnoDB can add column dynamically.
       
      The innodb comfort record format such as:
        [lens | n_nulls | n_fields | extra | id...]
          1. extra info_bits will occupy 1 bit to flag comfort.
          2. n_fields will occupy 1 or 2 bytes to save the column number.
       
      Then add column action will only change the dictionary and cache.
       
      Limition:
      ---------
      The column only can added at last, and nullable, non-default value.
       
      Usage:
      ------
      create table t (id int) engine=innodb row_format=comfort.
      alter table t add col1 int;
      

      https://github.com/alibaba/AliSQL/commit/70ad701de15cd1e872127ed01e016a193b4c723c

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              • Assignee:
                marko Marko Mäkelä
                Reporter:
                svoj Sergey Vojtovich
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