Re: Binary support for pgoutput plugin

Hi,


On Wed, 5 Jun 2019 at 07:18, Petr Jelinek <petr.jelinek@2ndquadrant.com>
wrote:

> Hi,
>
> On 05/06/2019 00:08, Andres Freund wrote:
> > Hi,
> >
> > On 2019-06-05 00:05:02 +0200, David Fetter wrote:
> >> Would it make sense to work toward a binary format that's not
> >> architecture-specific? I recall from COPY that our binary format is
> >> not standardized across, for example, big- and little-endian machines.
> >
> > I think you recall wrongly. It's obviously possible that we have bugs
> > around this, but output/input routines are supposed to handle a
> > endianess independent format. That usually means that you have to do
> > endianess conversions, but that doesn't make it non-standardized.
> >
>
> Yeah, there are really 3 formats of data we have, text protocol, binary
> network protocol and internal on disk format. The internal on disk
> format will not work across big/little-endian but network binary
> protocol will.
>
> FWIW I don't think the code for binary format was included in original
> logical replication patch (I really tried to keep it as minimal as
> possible), but the code and protocol is pretty much ready for adding that.
>
Yes, I looked through the public history and could not find it. Thanks for
confirming.

>
> That said, pglogical has code which handles this (I guess Andres means
> that by predecessor of pgoutput) so if you look for example at the
> write_tuple/read_tuple/decide_datum_transfer in
>
> https://github.com/2ndQuadrant/pglogical/blob/REL2_x_STABLE/pglogical_proto_native.c
> that can help you give some ideas on how to approach this.
>

Thanks for the tip!


Dave Cramer

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