Re: Bug? ExecChooseHashTableSize() got assertion failed with crazy number of rows

Kouhei Kaigai <kaigai(at)ak(dot)jp(dot)nec(dot)com> wrote:

> long lbuckets;

> lbuckets = 1 << my_log2(hash_table_bytes / bucket_size);

> Assert(nbuckets > 0);

> In my case, the hash_table_bytes was 101017630802, and bucket_size was 48.
> So, my_log2(hash_table_bytes / bucket_size) = 31, then lbuckets will have
> negative number because both "1" and my_log2() is int32.
> So, Min(lbuckets, max_pointers) chooses 0x80000000, then it was set on
> the nbuckets and triggers the Assert().

> Attached patch fixes the problem.

So you changed the literal of 1 to 1U, but doesn't that just double
the threshold for failure? Wouldn't 1L (to match the definition of
lbuckets) be better?

--
Kevin Grittner
EDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company