Thread

BUG #19356: Unexpected result of prepared UPDATE with force_generic_plan

PG Bug reporting form <noreply@postgresql.org> — 2025-12-16T03:06:11Z

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))))));`