Re: postgres reorders expressions when inlining

Поиск
Список
Период
Сортировка
От Tom Lane
Тема Re: postgres reorders expressions when inlining
Дата
Msg-id 553278.1672326872@sss.pgh.pa.us
обсуждение исходный текст
Ответ на postgres reorders expressions when inlining  (Floris Van Nee <florisvannee@Optiver.com>)
Список pgsql-bugs
Floris Van Nee <florisvannee@Optiver.com> writes:
> I recently ran into some behavior with inlining that seemed strange to me. I managed to break it down into a small
reproducibleexample that I've added. I originally ran into it in more complicated queries that involved inlining of SQL
functionsinstead of subqueries, but it reproduces with subqueries too so that's the example I've added. Tested on v15. 

> create table t1 as select a, b from generate_series(0, 5) a, generate_series(0, 10) b;
> select * from (
>    select a, b, c
>    from t1
>    left join lateral
>    (
>       select 1 / b as c
>    ) c on true
>    where b <> 0
> ) as o
> where o.c is not null

> The SELECT query leads to a division by zero. Plan:

This is not a bug.  We make no ordering guarantees about WHERE clause
execution; if we did, it would cripple the planner's ability to
optimize.

            regards, tom lane



В списке pgsql-bugs по дате отправления:

Предыдущее
От: "David G. Johnston"
Дата:
Сообщение: Re: postgres reorders expressions when inlining
Следующее
От: PG Bug reporting form
Дата:
Сообщение: BUG #17734: Doc bug: "initial database user" used where "bootstrap superuser" is meant