It is said to be safe, reliable and proven using complex algorithms and built-in intelligence where it can do the following (see this link for more details: https://docs.microsoft.com/en-us/azure/sql-database/sql-database-automatic-tuning)
- CREATE INDEX – identifies indexes that may improve performance of your workload, creates indexes, and automatically verifies that performance of queries has improved.
- DROP INDEX – identifies redundant and duplicate indexes daily, except for unique indexes, and indexes that were not used for a long time (>90 days). Please note that at this time the option is not compatible with applications using partition switching and index hints.
- FORCE LAST GOOD PLAN – identifies SQL queries using execution plan that is slower than the previous good plan, and queries using the last known good plan instead of the regressed plan.
Personally I don’t enable the option where it is allowed a “free-for-all” when creating/dropping indexes and forcing certain query plans. I like controlling the change, especially for production databases. To force this concept I wanted to use Extended Events to know when / if someone changed my settings for automatic tuning against my database.
Click through for the script.