On Thu, 23 Jan 2020 at 00:00, Tom Lane wrote:
> The problem is that the planner's initial analysis of the query tree
> concludes that the scan of "tab" has to return "x", because it looks
> through the tree for plain Vars, and "x" is what it's going to find.
> This conclusion is in fact true for a
Malthe writes:
> Referencing the example given in the documentation for index-only
> scans [0], we consider an index:
> CREATE INDEX tab_f_x ON tab (f(x));
> This index currently will not be used for an index-scan for the
> following query since the planner isn't smart enough to know that "x"
> is
Referencing the example given in the documentation for index-only
scans [0], we consider an index:
CREATE INDEX tab_f_x ON tab (f(x));
This index currently will not be used for an index-scan for the
following query since the planner isn't smart enough to know that "x"
is not needed:
SELECT f(x)
