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help / color / mirror / Atom feedFrom: David Rowley <[email protected]>
To: Tender Wang <[email protected]>
Cc: Andres Freund <[email protected]>
Cc: John Naylor <[email protected]>
Cc: PostgreSQL Developers <[email protected]>
Subject: Re: More speedups for tuple deformation
Date: Fri, 20 Mar 2026 14:18:12 +1300
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On Fri, 20 Mar 2026 at 01:56, David Rowley <[email protected]> wrote:
>
> On Fri, 20 Mar 2026, 01:39 Tender Wang, <[email protected]> wrote:
>> 1197 pg_assume(attlen > 0 || attlen == -1);
>> (gdb) p attlen
>> $1 = -2
>
>
> Thanks for the report. I'll look in detail in the morning when I'm at my computer again. I guess i'll need to add an extra parameter (that will be constant folded away during the inlining) to the deformed function to specify if cstrings can exist in the tuple, which seemingly needs to be true when deforming minimal tuples. I'd rather not lose that optimisation with heap tuples.
I've pushed a fix for this. A more simple recreator was:
with cte as materialized (select relname::cstring as relname from
pg_class) select relname from cte;
David
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Subject: Re: More speedups for tuple deformation
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