Re: Index Tuning Features

> Simon Riggs <simon@2ndquadrant.com> writes:

>> - RECOMMEND command
>
>> Similar in usage to an EXPLAIN, the RECOMMEND command would return a
>> list of indexes that need to be added to get the cheapest plan for a
>> particular query (no explain plan result though).
>
> Both of these seem to assume that EXPLAIN results, without EXPLAIN
> ANALYZE results to back them up, are sufficient for tuning.  I find
> this idea a bit dubious, particularly for cases of "marginal" indexes.


I think the idea of "virtual indexes" is pretty interesting, but
ultimately a lesser solution to a more fundimental issue, and that would
be "hands on" control over the planner. Estimating the effect of an index
on a query "prior" to creating the index is a great idea, how that is done
is something different than building concensus that it should be done.

Another thing that this brings up is "hints" to a query. Over the years, I
have run into situation where the planner wasn't great.  It would be nice
to try forcing different strategies on the planner and see if performance
caan be improved.