[GitHub] [airflow] potiuk edited a comment on issue #14354: airflow version 2.0.1 === airflow db upgrade error

[GitBox <gi...@apache.org>]

potiuk edited a comment on issue #14354:
URL: https://github.com/apache/airflow/issues/14354#issuecomment-784011866


   Then you probably have `utf8mb4` encoding. In such case you need to specify `sql_engine_collation_for_ids=utf8mb3_general_ci` parameter in Airflow's config before migration. This is due to limitations of MySQL - when utf8mb4 is used, each character takes 4 bytes and it exceed the maximum key size.
   
   We already have a chapter about it in the upcoming documentation (will be released with the next release of Airflow):
   
   https://github.com/apache/airflow/blob/master/docs/apache-airflow/howto/set-up-database.rst#setting-up-a-mysql-database
   
   ```
   In addition, you also should pay particular attention to MySQL's encoding. Although the utf8mb4 character set is more
   and more popular for MySQL (actually, utf8mb4 becomes default character set in MySQL8.0), using the utf8mb4 encoding
   requires additional setting in Airflow 2+ (See more details in #7570.). If you use utf8mb4 as character set, you should also set 
   sql_engine_collation_for_ids=utf8mb3_general_ci.
   ```
   
   


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