ALTER TABLE Statement per value from 1 byte to 2 bytes; this requires a table copy. Adding members in the middle of the list causes renumbering of existing members, which requires a table copy. An example of such a change is a change to the column comment. •Changing the definition of a spatial column to remove the  SRID  attribute. (Adding or changing an  SRID attribute does require a rebuild and cannot be done in place because the server must verify that all values have the specified SRID value.) •As of MySQL 8.0.14, changing a column character set, when these conditions apply: •The column data type is  CHAR ,  VARCHAR , a  TEXT  type, or  ENUM . •The character set change is from  utf8mb3  to  utf8mb4 , or any character set to  binary . •There is no index on the column. •As of MySQL 8.0.14, changing a generated column, when these conditions apply: •For  InnoDB  tables, statements that modify generated stored columns but do not change their type, expression, or nullability. •For non- InnoDB  tables, statements that modify generated stored or virtual columns but do not change their type, expression, or nullability. •Renaming an index. •Adding or dropping a secondary index, for  InnoDB  and  NDB  tables. See Section 15.12.1, “Online DDL Operations” . •For  NDB  tables, operations that add and drop indexes on variable-width columns. These operations occur online, without table copying and without blocking concurrent DML actions for most of their duration. See Section 23.5.11, “Online Operations with ALTER TABLE in NDB Cluster” . •Modifying index visibility with an  ALTER INDEX  operation. •Column modifications of tables containing generated columns that depend on columns with a  DEFAULT value if the modified columns are not involved in the generated column expressions. For example, changing the  NULL  property of a separate column can be done in place without a table rebuild. •Adding a column. This feature is referred to as “Instant  ADD COLUMN ” . Limitations apply. See Section 15.12.1, “Online DDL Operations” . •Adding or dropping a virtual column. •Adding or dropping a column default value. •Modifying the definition of an  ENUM  or  SET  column. The same restrictions apply as described above for ALGORITHM=INSTANT . •Changing the index type. •Renaming a table. The same restrictions apply as described above for  ALGORITHM=INSTANT . ALTER TABLE  operations that support the  INSTANT  algorithm include: For more information about operations that support  ALGORITHM=INSTANT , see Section 15.12.1, “Online DDL Operations” . 2488