Horton

Re: ERROR: XX000: could not find memoization table entry (reproducible)

David Rowley <dgrowleyml@gmail.com>

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From: David Rowley <dgrowleyml@gmail.com>
To: "pgsql-bugs@lists.postgresql.org" <pgsql-bugs@lists.postgresql.org>
Cc: Emmanuel Touzery <emmanuel.touzery@plandela.si>
Date: 2025-10-22T21:04:55Z
Lists: pgsql-bugs

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  1. Fix incorrect zero extension of Datum in JIT tuple deform code

On Thu, 23 Oct 2025 at 00:27, David Rowley <dgrowleyml@gmail.com> wrote:
> v_tmp_loaddata = LLVMBuildZExt(b, v_tmp_loaddata, TypeDatum, "");

> Will look more tomorrow.

This seems to be a 1 liner fix. Basically, the zero extend should be a
signed extend. i.e, use LLVMBuildSExt().

Using [1] to get the extra debug output.

set jit_Above_Cost=0;
drop table if exists b;
create table b (a char, b smallint, c int);
insert into b values('-100'::char,-123,-1234);
insert into b values('123'::char,1234,12345);
set jit=1;
select * from b where c <> 0;
set jit=0;
select * from b where c <> 0;

With the patch, I get:

NOTICE:  scan tuple = (a,b,c) (-,-123,-1234)
(124262785167352,18446744073709551493,18446744073709550382)
NOTICE:  scan tuple = (a,b,c) (1,1234,12345) (124262785167320,1234,12345)
 a |  b   |   c
---+------+-------
 - | -123 | -1234
 1 | 1234 | 12345
(2 rows)

SET
NOTICE:  scan tuple = (a,b,c) (-,-123,-1234)
(124262785167352,18446744073709551493,18446744073709550382)
NOTICE:  scan tuple = (a,b,c) (1,1234,12345) (124262785167320,1234,12345)
 a |  b   |   c
---+------+-------
 - | -123 | -1234
 1 | 1234 | 12345
(2 rows)

And without, I get:

NOTICE:  scan tuple = (a,b,c) (-,-123,-1234) (135890207272952,65413,4294966062)
NOTICE:  scan tuple = (a,b,c) (1,1234,12345) (135890207272920,1234,12345)
 a |  b   |   c
---+------+-------
 - | -123 | -1234
 1 | 1234 | 12345
(2 rows)

SET
NOTICE:  scan tuple = (a,b,c) (-,-123,-1234)
(135890207272952,18446744073709551493,18446744073709550382)
NOTICE:  scan tuple = (a,b,c) (1,1234,12345) (135890207272920,1234,12345)
 a |  b   |   c
---+------+-------
 - | -123 | -1234
 1 | 1234 | 12345
(2 rows)

David

[1] https://www.postgresql.org/message-id/attachment/183414/debug_scan_data.diff