If you’ve been working with MySQL for some time, you have probably heard the terms “table-level locking” and “row-level locking”. These terms refer to the lock granularity in MySQL — in this tutorial ...
MySQL uses Metadata Locks (MDL) to protect table definitions while queries are running. Any query that accesses a table (even a simple SELECT) acquires an MDL shared lock, while DDL operations (such ...
before 5.6, DDL has 2 implementations: COPY and INPLACE(INPLACE is just for index add and remove); in 5.6, online DDL is introduced; online DDL also has COPY and INPLACE implementations, so online DDL ...