Subject: Re: Stability of queryid in minor versions

From: "David G. Johnston" <[email-masked]>
Date: Sun, 14 Apr 2024 18:36:19 -0700

On Sun, Apr 14, 2024 at 4:20 PM David Rowley <[email-masked]> wrote:

>
> I've drafted a patch which I think improves things, but it probably
> needs more work and opinions.
>
>
Seems we can improve things by simply removing the "rule of thumb" sentence
altogether.  The prior paragraph states the things the queryid depends upon
at the level of detail the reader needs.

The sentence "Two servers participating in replication based on physical
WAL replay can be expected to have identical queryid values for the same
query." apparently assumes that to participate both servers must share the
same machine architecture.  I am under the impression that this is only an
advisory, not a requirement.  Rather, two servers participating in physical
replication will be ensured that the catalog metadata and major versions
are identical.  This is not the case for servers related via logical
replication.

David J.

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From: David Rowley <[email-masked]>
Date: Mon, 15 Apr 2024 14:03:02 +1200

On Mon, 15 Apr 2024 at 13:37, David G. Johnston
<[email-masked]> wrote:
> Seems we can improve things by simply removing the "rule of thumb" sentence altogether.  The prior paragraph states the things the queryid depends upon at the level of detail the reader needs.

I don't think that addresses the following, which I mentioned earlier:

> but not stable across *major* versions does *not* mean stable across
> *minor* versions. The reader is just left guessing if that's true.

David

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From: "David G. Johnston" <[email-masked]>
Date: Sun, 14 Apr 2024 19:23:33 -0700

On Sun, Apr 14, 2024 at 7:03 PM David Rowley <[email-masked]> wrote:

> > Seems we can improve things by simply removing the "rule of thumb"
> sentence altogether.  The prior paragraph states the things the queryid
> depends upon at the level of detail the reader needs.
>
The base assumption here is that changes in the things we don't mention do
not influence the queryid.  We didn't mention minor versions, changing them
doesn't influence the queryid.

Now, reading that entire paragraph is a bit of a challenge IMO, and agree,
as I subsequently noted, that the sentence you pointed out could be
reworked.  I stand by my statement that removing the sentence about "rule
of thumb" altogether is a win.  The prior paragraph should be sufficient -
it is technically at the moment but am not opposed to rewording.

David J.