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From: Michael Paquier <[email protected]>
To: Sami Imseih <[email protected]>
Cc: Lukas Fittl <[email protected]>
Cc: zengman <[email protected]>
Cc: pgsql-hackers <[email protected]>
Cc: Julien Rouhaud <[email protected]>
Subject: Re: Refactor query normalization into core query jumbling
Date: Sat, 28 Mar 2026 10:42:09 +0900
Message-ID: <[email protected]> (raw)
In-Reply-To: <CAA5RZ0ui6JSDPQDs2RW7eBDvrH_t_xg8bhUM8FaxawU8wDoMFg@mail.gmail.com>
References: <CAA5RZ0ui6JSDPQDs2RW7eBDvrH_t_xg8bhUM8FaxawU8wDoMFg@mail.gmail.com>



> On Mar 28, 2026, at 2:09, Sami Imseih <[email protected]> wrote:
> I agree that ComputeConstantLengths should be in core. This one is
> not a gray area IMO. The query jumble already records constant locations,
> but leaves the lengths unset. ComputeConstantLengths is just the
> completion of that  work. There could be no other interpretation,
> unlike generate_normalized_query, of what the lengths should be.

This is an interesting remark. One problem with any patches presented yet is that we don’t attach the lengths as part of the in-core query jumbling procedure: we plug the lengths later using the same structure as the query jumbling. It seems to me that this is half-baked overall. I think that we don’t want to pay the extra length computation in the core query jumbling at the end, then why does it make sense to include the lengths in the JumbleState structure at all? Shouldn’t we use a different structure filled inside PGSS for this purpose rather than reuse the same thing for PGSS and the in-core part (don’t have the code in front of me now).
--
Michael

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