Re: multivariate statistics v14

Hi,

On 03/22/2016 01:46 PM, Tatsuo Ishii wrote:
...
> Sorry, maybe I did not explain clearly. My question is, if put
> patches only 0002 to 0005 into 9.6, does it still give any visible
> benefit to users?

The users will be able to define statistics with the limitation that 
only a single one (the one covering the most columns referenced by the 
clauses) can be used when estimating a query. Which is not perfect, but 
I think it's a valuable improvement.

It might also be possible to split 0006 into smaller pieces, for example 
implementing the "non-overlapping statistics" case first and then 
extending it to more complicated cases. That might increase the change 
of getting at least some of that into 9.6 ...

But considering it's not clear whether the initial chunks are likely to 
make it into 9.6 - I kinda expect a fair amount of comments from TL 
about the preceding parts, who mentioned he might look at the patch this 
week. So I'm not sure splitting 0006 into smaller pieces makes sense at 
this point.

regards

-- 
Tomas Vondra                  http://www.2ndQuadrant.com
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