"Robert Haas" <robertmh...@gmail.com> writes: > I had this idle thought too, but I didn't write it down because...
>> ought to be, but it seems like it ought to be possible to determine >> that given a desired maximum error in the overall estimate. I'm also >> not very clear on what the "total frequency" computations (matchfreq2 >> and unmatchfreq2 in the current code) ought to look like if we are using >> a variable subset of the inner list. > ...of this exact concern, which I think is an insurmountable problem. Maybe so. If we stick to the other design (end both lists at a preset frequency threshold) then the math clearly goes through the same as before, just with num_mcvs that are determined differently. But can we prove anything about the maximum error added from that? regards, tom lane -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers