| From: | Andres Freund <andres(at)2ndquadrant(dot)com> |
|---|---|
| To: | Robert Haas <robertmhaas(at)gmail(dot)com> |
| Cc: | Erik Rijkers <er(at)xs4all(dot)nl>, "pgsql-hackers(at)postgresql(dot)org" <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: Changeset Extraction v7.6.1 |
| Date: | 2014-02-21 13:27:33 |
| Message-ID: | 20140221132733.GB28858@alap3.anarazel.de |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-hackers |
On 2014-02-21 08:16:59 -0500, Robert Haas wrote:
> On Fri, Feb 21, 2014 at 6:07 AM, Andres Freund <andres(at)2ndquadrant(dot)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
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