Re: surprisingly expensive join planning query

Tomas Vondra <tomas(dot)vondra(at)2ndquadrant(dot)com> writes:
> On Sun, Dec 01, 2019 at 01:27:04PM -0500, Tom Lane wrote:
>> Alternatively, it'd be possible to get rid of the separate List
>> altogether, and just add the rinfo's to "mergeclauses" immediately.
>> The functionality of the separate list could be replaced by a
>> bool variable remembering whether we found any matches in this
>> pass through the loop. I think the code would be a little less
>> clear that way, but this report makes it clear that it's a
>> performance bottleneck, so maybe we should just change it.

> Yes, that might be an option. And it works even on 9.5 for me (per the
> attached patch). I don't think it's much less clear compared to just
> doing an explicit free at the end.

LGTM.

regards, tom lane