On 2019-Feb-13, Alvaro Herrera wrote:
> It definitely is ... plans have changed from using IndexOnly scans to
> Seqscans, which is likely fallout from the visibilitymap_count() change.
I think the problem here is that "unsigned long" is 32 bits in this
machine:
checking whether long int is 64 bits... no
and we have defined pg_popcount64() like this:
static int
pg_popcount64_sse42(uint64 word)
{
return __builtin_popcountl(word);
}
so it's counting bits in the lower half of the uint64.
If that's correct, then I think we need something like this patch. But
it makes me wonder whether we need a configure test for
__builtin_popcountll() and friends. I wonder if there's any compiler
that implements __builtin_popcountl() but not __builtin_popcountll() ...
and if not, then the test for __builtin_popcountl() should be removed,
and have everything rely on the one for __builtin_popcount().
--
Álvaro Herrera https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
