Re: Changeset Extraction v7.6.1

On 2014-02-21 08:16:59 -0500, Robert Haas wrote:
> On Fri, Feb 21, 2014 at 6:07 AM, Andres Freund <andres@2ndquadrant.com> wrote:
> > I can sympathize with the "too much during init" argument, but I don't
> > see how moving stuff to the first call would get rid of the problems. If
> > we fail later it's going to be just as confusing.
> 
> No, it isn't.  If you fail during init the use will expect the slot to
> be gone.  That's the reason for all of this complexity.  If you fail
> on first use, the user will expect the slot to still be there.

The primary case for failing is a plugin that either doesn't exist or
fails to initialize, or a user aborting the init. It seems odd that a
created slot fails because of a bad plugin or needs to wait till it
finds a suitable snapshot record. We could add an intermediary call like
pg_startup_logical_slot() but that doesn't seem to have much going for
it?

Greetings,

Andres Freund

-- Andres Freund                       http://www.2ndQuadrant.com/PostgreSQL Development, 24x7 Support, Training &
Services