[development] User Status [WAS: User last access]

[David Timothy Strauss]

I couldn't care less about the SQL92 standard (or any other SQL standard).

What I care about is:
* What we do is space efficient on MySQL
* What we do is fast on MySQL
* What we do works on other databases

SQL92 doesn't answer any of those questions for me.

Consequently, I have a few goals if we implement status bits for user accounts:
* Not having one byte per bit
* Not having O(n) searches for common bit-status user queries, if we have such queries
* Ability to run on other databases, without significant regard to performance or space efficiency

"Make the common case fast."
<http://en.wikipedia.org/wiki/Amdahl%27s_law>

----- "Ivan Sergio Borgonovo" <mail at webthatworks.it> wrote:

> On Sat, 3 May 2008 19:12:46 +0000
> "David Strauss" <david at fourkitchens.com> wrote:
> 
> > But they probably support another bit-based format.
> 
> The smallest thing you can find in SQL92 I think is boolean.
> As said most DB support bit packing and some have aggregate functions
> over boolean fields.
> 
> char doesn't look as a good choice because on UTF8 may have some
> overhead, it is ordered according to locale and in need it misses
> interesting aggregate functions.
> I don't know SQL standards and enough implementations to know if you
> can avoid both problems in most DB.
> Some DB let you define collation and encoding on a field base... some
> don't even let you define the encoding/collation on a table base.
> 
> The smallest SQL92 int is 2 bytes (smallint) someone may think it is
> too large but it is very well handled by modern CPU and is not
> affected by locale nor encoding... if you've more statuses...
> 
> -- 
> Ivan Sergio Borgonovo
> http://www.webthatworks.it