Re: Changeset Extraction v7.6.1

On Fri, Feb 21, 2014 at 8:27 AM, Andres Freund <andres(at)2ndquadrant(dot)com> wrote:
> 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?

Well, we can surely detect a plugin that fails to initialize before
creating the slot on disk, right?

I'm not sure what "fails to initialize" entails.

--
Robert Haas
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