Re: "large" IN/NOT IN subqueries result in query returning wrong data

"George Pavlov" <gpavlov@mynewplace.com> writes:
> select count(*) from t2 where t2.name not in (
>   select t1.name from t1 limit 261683) 
> --> 13
> select count(*) from t2 where t2.name not in (
>   select t1.name from t1 limit 261684) 
> --> 0

> What is so magical about 261683?

Most likely, the 261684'th row of t1 has a NULL value of name.
Many people find the behavior of NOT IN with nulls unintuitive,
but it's per SQL spec ...
        regards, tom lane