Re: Hypothetical Indexes - Mailing list pgsql-hackers

From Tom Lane
Subject Re: Hypothetical Indexes
Date
Msg-id 6710.1097614963@sss.pgh.pa.us
Whole thread Raw
In response to Hypothetical Indexes  (Marcos A Vaz Salles <msalles@gmail.com>)
Responses Re: Hypothetical Indexes
Re: Hypothetical Indexes
List pgsql-hackers
Marcos A Vaz Salles <msalles@gmail.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


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