Re: benchmarking the query planner

On Thu, 2008-12-11 at 17:45 -0500, Tom Lane wrote:
> Simon Riggs <simon@2ndQuadrant.com> writes:
> > I would like it even more if there was a data type specific default.
> > Currently we have a special case for boolean, but that's it.
> 
> No, we don't (or if we do I'd be interested to know where). 

Your commit, selfuncs.c, 7 Jul.

>  I don't see
> much value in a data-type-dependent default anyway --- would you make
> different defaults for int4, int8, and float8, and on what grounds?
> The actual data contents of three such columns could easily be exactly
> equivalent.

I would prefer distinct type or domain specific defaults, but until we
have that I would settle for datatype specific defaults. 

Defaults, not only permissible settings.

Most people don't keep same data in float8 as they do in int4, but
neither of those were ones I was thinking about. I see 3 main classes:
* data with small number of distinct values (e.g. boolean, smallint)
* data with many distinct values
* data with where every value is typically unique (e.g. text)

-- Simon Riggs           www.2ndQuadrant.comPostgreSQL Training, Services and Support