>> >> > One more problem with low ndistinct values is that the condition might very well
>> >> > hit no rows at all. But Idea 1 will largely overestimate the number of hits.
>>
>> Thats a good point, but I don't see a clear solution. Maybe we could
>
> I think that MCVs are the solution, right?
Only if they cover the entire range of values in the table.
> A low ndistinct means that those values will likely be MCVs.
Yes, but I don't think thats the point.
If we query on values that aren't in the table, the planner will
always overestimate the expected number of returned rows because it (
implicitly ) assumes that every query will return at least 1 record.
