Re: Multivariate statistics and expression indexes

On Tue, Feb 21, 2017 at 01:27:53AM +0100, Tomas Vondra wrote:
> On 02/21/2017 12:13 AM, Bruce Momjian wrote:
> >At the risk of asking a stupid question, we already have optimizer
> >statistics on expression indexes.  In what sense are we using this for
> >multi-variate statistics, and in what sense can't we.
> >
> 
> We're not using that at all, because those are really orthogonal features.
> Even with expression indexes, the statistics are per attribute, and the
> attributes are treated as independent.
> 
> There was a proposal to also allow creating statistics on expressions
> (without having to create an index), but that's not supported yet.

OK, thanks.  I had to ask.

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  Bruce Momjian  <bruce@momjian.us>        http://momjian.us
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