DDL replication v5

DDL stands for data definition language, the subset of the SQL language that creates, alters, and drops database objects.

PGD provides automatic DDL replication, which makes certain DDL changes easier. With automatic replication, you don't have to manually distribute the DDL change to all nodes and ensure that they're consistent.

This section looks at how DDL replication is handled in PGD.

• Overview provides a general outline of what PGD's DDL replication is capable of.

• Replication options looks at the options for controlling replication.

• Locking examines how DDL replication uses locks to safely replicate DDL.

• Managing DDL with PGD replication gives best practice advice on why and how to limit the impact of DDL changes so they don't overly affect the smooth running of the cluster.

• Command handling is a reference to all DDL commands, the locks they take, and any special handling involved in their use and execution.

• DDL role manipulation notes issues around manipulating roles over multiple databases in a cluster.

• Workarounds gives a range of options for handling situations where DDL replication may present restrictions, such as altering columns, constraints, and types.

• DDL-like PGD functions details the PGD functions that behave like DDL and therefore behave in a similar way and are subject to similar restrictions.