Use cases for creating event triggers

In addition to an audit trail, the following can be valid use cases for an event trigger:

• Replicating DDL changes to a remote location
• Cascading a DDL
• Preventing changes to tables, except during a predefined window
• Providing limited DDL capability to developers / support staff using security definer functions
• Disabling certain DDL commands based on a criteria
• Performance analysis to see how long a command takes between ddl_command_start and ddl_command_end

Note that the event trigger support for PL/pgsql is not yet complete in 9.3. There are several features that are being worked upon and will be available in future PostgreSQL versions, hopefully. These are a few of the most notable features that are missing so far:

• There's no information about the object that a DDL targets
• There's no access to the command string
• There's no support for the generated commands

A command such as CREATE TABLE foo (id serial PRIMARY KEY) will also result in the CREATE...