Re: [HACKERS] logical decoding of two-phase transactions

On 2018-08-01 21:55:18 +0200, Petr Jelinek wrote:
> On 01/08/18 16:00, Nikhil Sontakke wrote:
> > 
> >> I was wondering if anything else would be needed for user-defined
> >> catalog tables..
> >>
> > 
> > We don't need to do anything else for user-defined catalog tables
> > since they will also get accessed via the systable_* scan APIs.
> > 
> 
> They can be, but currently they might not be. So this requires at least
> big fat warning in docs and description on how to access user catalogs
> from plugins correctly (ie to always use systable_* API on them). It
> would be nice if we could check for it in Assert builds at least.

Yea, I agree. I think we should just consider putting similar checks in
the general scan APIs. With an unlikely() and the easy predictability of
these checks, I think we should be fine, overhead-wise.

Greetings,

Andres Freund