Improvement of Aurora 3
- Multi-threaded replication
- replication lag が下がる = 同期が早くなる。
- supports instant DDL
- This feature significantly speeds up supported schema changes like adding a column, setting or dropping column default values, renaming a table, and more.
- also don’t exclusively lock the tables being changed. Because the instant DDL operations only modify metadata in the data dictionary, without metadata locks on the table
- New index types
- Aurora MySQL 3 now supports descending and invisible index types.
- Descending indexes improve the performance of queries that need to sort and retrieve from indexes in descending order.
- Invisible indexes allow you to test the performance impact of removing an index without actually dropping the index.
MySQL 8.0.x Knowledge
What atomic DDL is;
An atomic DDL statement combines the data dictionary updates, storage engine operations, and binary log writes associated with a DDL operation into a single, atomic operation.