On 2017/06/23 6:28, Alvaro Herrera wrote:
Ashutosh Bapat wrote:
On Mon, Jun 5, 2017 at 8:22 AM, atorikoshi
I found below formula to compute selectivities, but
I think the last Probability 'P(b=?)' should be 'P(c=?)'.
P(a=?,b=?,c=?) = P(a=?,b=?) * (d + (1-d)*P(b=?))
Attached patch fixes it, and it also adds some spaces
following another formula which is on line 86 and
computes P(a=?, b=?).
Agree. Also using "d" for "degree of functional dependence (b=>c) as
well is confusing. We are already using "d" for "degree of functional
dependence (a=>b). Here' patch to use "d'" instead of "d".
Since the surrounding text uses single quotes to talk about each letter,
I thought it was better to use a new letter (e) so that we don't require
the "prime" notation, which would end up being either inconsistent,
confusing, stupid-looking, or combinations thereof.
Also, your proposed text had a slight mistake: it's not (b=>c) that
d' is for, but (a,b=>c).
Pushed with those corrections.
Thanks for the reports and patches!
NIPPON TELEGRAPH AND TELEPHONE CORPORATION
NTT Open Source Software Center
Sent via pgsql-hackers mailing list (email@example.com)
To make changes to your subscription: