Thread

Re: BUG #19356: Unexpected result of prepared UPDATE with force_generic_plan

Tender Wang <tndrwang@gmail.com> — 2025-12-26T07:20:58Z

ZhangChi <798604270@qq.com> 于2025年12月26日周五 15:00写道：

> Hi,
>
> Has anyone had a look at this report?
>
> Best,
> Chi
>
> Original
> ------------------------------
> From: PG Bug reporting form <noreply@postgresql.org>
> Date: 2025-12-16 11:06
> To: pgsql-bugs <pgsql-bugs@lists.postgresql.org>
> Cc: 798604270 <798604270@qq.com>
> Subject: BUG #19356: Unexpected result of prepared UPDATE with
> force_generic_plan
>
> The following bug has been logged on the website:
>
> Bug reference:      19356
> Logged by:          Chi Zhang
> Email address:      798604270@qq.com
> PostgreSQL version: 17.6
> Operating system:   ubuntu 24.04 with docker
> Description:
>
> Hi,
>
> In the following test case, the WHERE condition of UPDATE is true; however,
> the value in the table is not updated:
>
> ```
> SET plan_cache_mode = force_generic_plan;
> CREATE TABLE t2(c0 int4range);
>
> INSERT INTO t2(c0) VALUES('[-1372225904,-410785016)'::int4range) ON CONFLICT
> DO NOTHING;
> PREPARE prepare_query (text, int4range, text, text, inet) AS UPDATE t2 SET
> c0=DEFAULT WHERE NOT (((((CAST($1 AS
> int4range))&&(((t2.c0)-($2)))))AND((quote_literal($3) SIMILAR TO
> (($4)||($5))))));
> EXECUTE prepare_query('-2073583882', '[-1190073754,1650158810)'::int4range,
> '?', 'j&Q', '171.191.143.34');
> DEALLOCATE prepare_query;
> SELECT DISTINCT * FROM t2;
>             c0
> --------------------------
>  [-1372225904,-410785016)
> (1 row)
> ```
>
> This is the result of the condition:
> ```
> PREPARE prepare_query (text, int4range, text, text, inet) AS SELECT
> ((((quote_literal($3) SIMILAR TO (($4)||($5))))));
> EXECUTE prepare_query('-2073583882', '[-1190073754,1650158810)'::int4range,
> '?', 'j&Q', '171.191.143.34');
>  ?column?
> ----------
>  f
> (1 row)
> ```
>
>
> The equivalent normal UPDATE can execute correctly `UPDATE t2 SET c0=DEFAULT
> WHERE NOT (((((CAST('-2073583882'::text AS
>
> int4range))&&(((t2.c0)-('[-1190073754,1650158810)'::int4range)))))AND((quote_literal('?'::text)
> SIMILAR TO (('j&Q'::text)||('171.191.143.34'::inet))))));`
>
>
>
I run your SQL on 17.6, I got this:
postgres=# select version();
                                                 version
---------------------------------------------------------------------------------------------------------
 PostgreSQL 17.6 on x86_64-pc-linux-gnu, compiled by gcc (Ubuntu
11.4.0-1ubuntu1~22.04.2) 11.4.0, 64-bit
(1 row)

postgres=# SET plan_cache_mode = force_generic_plan;
CREATE TABLE t2(c0 int4range);
INSERT INTO t2(c0) VALUES('[-1372225904,-410785016)'::int4range) ON CONFLICT
DO NOTHING;
PREPARE prepare_query (text, int4range, text, text, inet) AS UPDATE t2 SET
c0=DEFAULT WHERE NOT (((((CAST($1 AS
int4range))&&(((t2.c0)-($2)))))AND((quote_literal($3) SIMILAR TO
(($4)||($5))))));
EXECUTE prepare_query('-2073583882', '[-1190073754,1650158810)'::int4range,
'?', 'j&Q', '171.191.143.34');
DEALLOCATE prepare_query;
SELECT DISTINCT * FROM t2;
SET
CREATE TABLE
INSERT 0 1
PREPARE
ERROR:  malformed range literal: "-2073583882"
DETAIL:  Missing left parenthesis or bracket.
DEALLOCATE
            c0
--------------------------
 [-1372225904,-410785016)
(1 row)

EXECUTE prepare_query('-2073583882', '[-1190073754,1650158810)'::int4range,
'?', 'j&Q', '171.191.143.34');
This SQL reported error: malformed range literal: "-2073583882", so it did
nothing.

-- 
Thanks,
Tender Wang