Re: pgsql: Change timeline field of IDENTIFY_SYSTEM to int8

Peter Eisentraut <peter(dot)eisentraut(at)enterprisedb(dot)com> writes:
> On 04.07.22 07:55, Tom Lane wrote:
>> But what about whatever code is reading the output? And what if
>> that code isn't v16? I can't believe that we can make a wire
>> protocol change as summarily as this.

> I think a client will either just read the string value and convert it
> to some numeric type without checking what type was actually sent, or if
> the client API is type-aware and automatically converts to a native type
> of some sort, then it will probably already support 64-bit ints. Do you
> see some problem scenario?

If the result of IDENTIFY_SYSTEM is always sent in text format, then
I agree that this isn't very problematic. If there are any clients
that fetch it in binary mode, though, this is absolutely a wire
protocol break for them ... and no, I don't believe an unsupported
claim that they'd adapt automatically.

> I'm seeing a bigger problem now, which is that our client code doesn't
> parse bigger-than-int32 timeline IDs correctly.

Yup.

regards, tom lane