Re: pgsql: Support partition pruning at execution time

On 10 April 2018 at 09:58, Alvaro Herrera <alvherre(at)alvh(dot)no-ip(dot)org> wrote:
> I then noticed that support for nfiltered3 was incomplete; hence 0001.
> (I then noticed that nfiltered3 was added for MERGE. It looks wrong to
> me.)
>
> Frankly, I don't like this. I would rather have an instrument->ntuples2
> rather than these "divide this by nloops, sometimes" schizoid counters.
> This is already being misused by ON CONFLICT (see "other_path" in
> show_modifytable_info). But it seems like a correct fix would require
> more code.

+1 for a new field for this and making ON CONFLICT use it.

ntuples2 seems fine. If we make it too specific then we'll end up with
lots more than we need.

I don't think re-using the filter counters are very good when it's not
for filtering.

MERGE was probably just following the example made by ON CONFLICT.

--
David Rowley http://www.2ndQuadrant.com/
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