Re: Using null date fields to indicate active/expired records

Brian,

> Approximately 14 billion. Ok, I'm kidding, but can anyone answer my
> question? Although this might be micro-optimization, does it hurt to
> know more about date performance?

No, there's nothing wrong with knowing. What David and I are asserting is
that your decision should be determined by having a correct data model, and
not by counting bits, unless you're in a really extreme situation where you
have already tested and know you have a problem.

Josh's Database Rules #3: the performance loss for slow queries is generally
exceeded by the downtime caused by a bad data model by a factor of 100 or
more.

> There are two parts to my question; one, which is faster, and two, does
> anyone have any advice about using either a single boolean flag or using
> a 1-n type date?

Which is faster depends on your query structure and the distribution of your
data; that's the other reason not to make decisions on this basis now. If
you want a serious answer on this, please post your current table structure
and an explanation of what kind of data is kept in the various fields and how
you query it.

--
-Josh Berkus
Aglio Database Solutions
San Francisco