Robert Haas wrote:
On Sat, Sep 5, 2009 at 8:19 PM, Karl Denninger<karl@denninger.net> wrote:
There was a previous thread and I referenced it. I don't have the other one
in my email system any more to follow up to it.
I give up; the attack-dog crowd has successfully driven me off. Ciao.
Perhaps I'm biased by knowing some of the people involved, but I don't
think anyone on this thread has been anything but polite. It would
certainly be great if PostgreSQL could properly estimate the
selectivity of expressions like this without resorting to nasty hacks,
but it can't, and unfortunately, there's really no possibility of that
changing any time soon. Even if someone implements a fix today, the
soonest it will appear in a production release is June 2010. So, any
suggestion for improvement is going to be in the form of suggesting
that you modify the schema in some way. I know that's not really what
you're looking for, but unfortunately it's the best we can do.
As far as I can tell, it is not correct to say that you referenced the
previous thread. I do not see any such reference.
...Robert
I was asking about modifying the schema.
The current schema is an integer being used as a bitmask. If the planner knows how to handle a type of "bit(X)" (and will at least FILTER rather than NESTED LOOP it on a select, as happens for an Integer used in this fashion), that change is easier than splitting it into individual boolean fields.
-- Karl