Re: Command Triggers patch v18

Robert Haas <robertmhaas(at)gmail(dot)com> writes:
> I think we're talking past each other. If someone executes DDL
> command A and the command trigger executes DDL command B which fires
> another command trigger, then the command trigger for A needs to see
> the information relevant to A both before and after the command
> trigger for B executes. So you can't just store all the context
> information in a flat global variable, because otherwise when the
> trigger for B executes it will clobber the values for A. You need to
> do a save/restore so that when the execution of the trigger on A
> resumes, it still sees the right stuff.

Agreed. I was trying to say that we won't have all of this in 9.2.

>> Yeah, just omit the WHEN clause then.
>
> Well, that's "absolutely everything" rather than just "all DDL".
> What's the use case for that?

You can still filter in the trigger code. A use case is forbidding any
command that's not purely data related to happen in certain cases, like
live server migrations.

--
Dimitri Fontaine
http://2ndQuadrant.fr PostgreSQL : Expertise, Formation et Support