Обсуждение: [bug report] A sql statements make query hang
Hi,
When we run follow statements make query hang and never return in PostgreSQL 13devel, we consider it might be a bug of PostgreSQL and report it.
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CREATE TEMPORARY TABLE v0 ( v1 INT UNIQUE ) ;
WITH RECURSIVE v0 ( v1 ) AS ( SELECT -128 UNION SELECT v1 + 33 FROM v0 ) SELECT 'x' from v0;
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When we run in mysql, it suddenly return an empty set.
Best,
Yongheng & Rui
Rui Zhong <reversezr33@gmail.com> writes:
> When we run follow statements make query hang and never return in
> PostgreSQL 13devel, we consider it might be a bug of PostgreSQL and report
> it.
> CREATE TEMPORARY TABLE v0 ( v1 INT UNIQUE ) ;
> WITH RECURSIVE v0 ( v1 ) AS ( SELECT -128 UNION SELECT v1 + 33 FROM v0 )
> SELECT 'x' from v0;
That's an infinite recursion, so I'm not sure why you think there's
a server bug here.
In practice, I think you'd get an integer overflow error after
awhile, where "awhile" is defined as INT_MAX/33 recursions.
It might take considerable patience to reach that point though.
(And when you did, it still wouldn't be a bug. The calculation
specified by this query must eventually overflow any finite
arithmetic.)
> When we run in mysql, it suddenly return an empty set.
Hardly requires commentary.
regards, tom lane