table-locking

[2017] Update: MySQL 5.6 has support for online index updates https://dev.mysql.com/doc/refman/8.0/en/innodb-online-ddl-operations.html#online-ddl-index-syntax-notes In MySQL 5.6 and higher, the table remains available for read and write operations while the index is being created or dropped. The CREATE INDEX or DROP INDEX statement only finishes after all transactions that are accessing the table are completed, so that the … Read more