Re: pg_advisor schema proof of concept

Fabien COELHO <coelho@cri.ensmp.fr> writes:
>>> (1) should it use pg_catalog.* or information_schema.*?
>> 
>> Not sure portability is important, but using information_schema will
>> presumably make it less likely that things will change between versions.

> Another issue I found is that, although all the contents of
> information_schema can be found in pg_catalog (as it derives from it!) not
> all of pg_catalog may be found in information_schema...

This is necessarily so, as the information_schema by definition covers
only concepts standardized by the SQL spec.  Since the SQL spec
considers things like indexes to be implementation details, it is simply
not possible for information_schema to tell you everything you want to
know to give performance advice.

>> If plpgsql works OK, I say stick with it.

> Hmmm. I'm not very happy with plpgsql,

I don't know where you are planning on going with this.  If it's only to
be a contrib tool, it's okay to depend on plpgsql.  But we couldn't
incorporate it into the base system because plpgsql isn't part of the
base system.
        regards, tom lane