Alter MySQL table without locking

In case you are not sure if an ALTER TABLE will copy and/or block the table, and you want to make sure your DDL statement won’t cause such problems, you can add new alter specifications to the statement: ALGORITHM and LOCK.

ALTER TABLE i88ca ENGINE=InnoDB, LOCK=NONE;

ALGORITHM [=] {DEFAULT|INPLACE|COPY}

LOCK [=] {DEFAULT|NONE|SHARED|EXCLUSIVE}