Marcos A Vaz Salles <msalles(at)gmail(dot)com> writes:
> In order to make index selection possible, we
> have extended the PostgreSQL DBMS to allow the simulation of
> hypothetical indexes. We believe these server extensions may be of
> value for addition to the PostgreSQL code base.
This would be of some value if the optimizer's cost estimates were
highly reliable, but unfortunately they are far from being so :-(
Without the ability to measure *actual* as opposed to estimated
costs, I'm not sure you can really do much.
regards, tom lane