> Following the formula outlined
> in http://www.postgresql.org/docs/8.3/static/row-estimation-examples.html
> Both gradrate 10 and gradrate 11 would fall in the first bucket.
> Shouldn't the row estimation be:
> (11 - 8) / (33 - 8) / 10 * 1302 = 15.624
> and
> (10 - 8) / (33 - 8) / 10 * 1302 = 10.416
> instead of 11 and 7?
> Perhaps I am missing something. I'd appreciate if you can point it out.
IIRC, you need to subtract the rows that are mcv's from the row count.
ie, you're not working with the full 1302 rows, only the ones that are
not mcv's.
Best,
Nathan