Re: bad estimation together with large work_mem generates terrible slow hash joins

On 10/02/2014 03:20 AM, Kevin Grittner wrote:
> My only concern from the benchmarks is that it seemed like there
> was a statistically significant increase in planning time:
>
> unpatched plan time average: 0.450 ms
> patched plan time average:   0.536 ms
>
> That *might* just be noise, but it seems likely to be real.  For
> the improvement in run time, I'd put up with an extra 86us in
> planning time per hash join; but if there's any way to shave some
> of that off, all the better.

The patch doesn't modify the planner at all, so it would be rather 
surprising if it increased planning time. I'm willing to just write that 
off as noise.

- Heikki