MySQL 8 is not using INDEX when subquery has a group column
Posted by: Rahul n
Date: November 25, 2019 11:31PM
We have just moved from mariadb 5.5 to MySQL 8 and some of the update queries have suddenly become slow. On more investigation, we found that MySQL 8 does not use index when the subquery has group columm.
For example, below is a sample database. Table `users` maintain the current balance of the users per type and table 'accounts' maintain the total balance history per day.
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