Re: Timeline following for logical slots

On Tue, Apr 26, 2016 at 4:35 PM, Alvaro Herrera
<alvherre(at)2ndquadrant(dot)com> wrote:
> Craig Ringer wrote:
>> The reason the new src/test/recovery/ tests don't notice this is that using
>> pg_recvlogical from the TAP tests is currently pretty awkward.
>> pg_recvlogical has no way to specify a stop-point or return when there's no
>> immediately pending data like the SQL interface does. So you have to read
>> from it until you figure it's not going to return anything more then kill
>> it and look at what it did return and hope you don't lose anything in
>> buffering.I don't much like relying on timeouts as part of normal
>> successful results since they can upset some of the older and slower
>> buildfarm members. I'd rather be able to pass a --stoppos= or a --n-xacts=
>> option, but it was a bit too late to add those.
>
> Considering that pg_recvlogical was introduced mostly as a way to test
> logical decoding features, I think this is a serious oversight and we
> should patch it. I suppose we could leave it for 9.7, thought I admit I
> would prefer it to introduce it in 9.6. Now everyone throwing stones at
> me in 3 ... 2 ...

If that's a small and relatively contained change, I don't object to
the idea of you making it, provided it's done pretty soon, and
definitely before beta1. If it's going to require substantial
refactoring or can't be done quickly, then, yes, I object.

--
Robert Haas
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