> > I went through the code (7.4 beta2) that estimates the cost of an index
> > scan path.  What I need to be sure of is that when running a query in
> > pgsql that uses only the columns that are in an index, the underlying
> > table need not be accessed.  I know that Oracle does this.

PostgreSQL absolutely does not do this.  It is also not possible to do this
due to MVCC.


---------------------------(end of broadcast)---------------------------
TIP 9: the planner will ignore your desire to choose an index scan if your
      joining column's datatypes do not match

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