Re: compute_query_id and pg_stat_statements

On Tue, May 11, 2021 at 05:41:06PM +0800, Julien Rouhaud wrote:
> On Tue, May 11, 2021 at 10:59:51AM +0200, Magnus Hagander wrote:
> > 
> > That doesn't fundamentally make it impossible, you just have to add it
> > to the list of variables being copied over, wouldn't you? See
> > save_backend_variables()
> 
> Yes, I agree, and that's what I meant by "explicitly handled".  The thing is
> that I don't know if that's the best way to go, as it doesn't solve the "is it
> actually enabled" and/or "which implementation is used".  At least the patch I
> sent, although it's totally a hack, let you know if compute_query_id is enabled
> or not.  I'm fine with implementing it that way, but only if there's a
> consensus.

Actually, isn't that how e.g. wal_buffers = -1 is working?  The original value
is lost and what you get is the computed value.  This is a bit different here
as the value isn't always changed, and can be changed interactively but
otherwise it's the same behavior.