Amazon Aurora can now execute one of the most common Data Definition Language (DDL) operations – an ALTER command to add a nullable column at the end of a table – nearly instantaneously. This capability, called fast DDL, is available in lab mode. Fast DDL doesn’t require a table copy and does not materially impact other DML statements. Since it doesn’t consume temporary storage for a table copy, it makes DDL statements practical even for large tables on small instance types. Take a look under the hood for how we accomplish this.