Re: Logical replication from PG v13 and below to PG v14 (devel version) is not working.

On Thu, Sep 24, 2020 at 4:45 PM Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
>
> On Thu, Sep 24, 2020 at 4:31 PM Dilip Kumar <dilipbalaut(at)gmail(dot)com> wrote:
> >
> > On Thu, Sep 24, 2020 at 11:55 AM Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
> > >
> > > On Tue, Sep 22, 2020 at 5:15 PM Dilip Kumar <dilipbalaut(at)gmail(dot)com> wrote:
> > > >
> > > > On Tue, Sep 22, 2020 at 12:02 PM Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
> > > > >
> > > > >
> > > > > I am not sure if this suggestion makes it better than what is purposed
> > > > > by Dilip but I think we can declare them in define number order like
> > > > > below:
> > > > > #define LOGICALREP_PROTO_MIN_VERSION_NUM 1
> > > > > #define LOGICALREP_PROTO_VERSION_NUM 1
> > > > > #define LOGICALREP_PROTO_STREAM_VERSION_NUM 2
> > > > > #define LOGICALREP_PROTO_MAX_VERSION_NUM LOGICALREP_PROTO_STREAM_VERSION_NUM
> > > >
> > > > Done this way.
> > > >
> > >
> > > - options.proto.logical.proto_version = LOGICALREP_PROTO_VERSION_NUM;
> > > + options.proto.logical.proto_version = MySubscription->stream ?
> > > + LOGICALREP_PROTO_STREAM_VERSION_NUM : LOGICALREP_PROTO_VERSION_NUM;
> > >
> > > Here, I think instead of using MySubscription->stream, we should use
> > > server/walrecv version number as we used at one place in tablesync.c.
> >
> > I am not sure how can we do this?
> >
>
> Have you checked what will function walrcv_server_version() will
> return? I was thinking that if we know that subscriber is connected to
> Publisher version < 14 then we can send the right value.

But, suppose we know the publisher version is < 14 and user has set
streaming on while creating subscriber then still we will send the
right version? I think tablesync we are forming a query so we are
forming as per the publisher's version. But here we are sending which
protocol version we are expecting for the data transfer so I feel it
should be LOGICALREP_PROTO_VERSION_NUM if we expect non-streaming
transfer and LOGICALREP_PROTO_STREAM_VERSION_NUM if we expect the
streaming transfer. Now let the publisher decide whether it supports
the protocol we have asked for or not and if it doesn't support then
let it give error. Am I missing something here?

--
Regards,
Dilip Kumar
EnterpriseDB: http://www.enterprisedb.com