On Wed, 2023-08-02 at 01:14 -0400, Isaac Morland wrote:
> I don’t think the fact that an optimization might suddenly not work
> in a certain situation is a reason not to optimize. What would our
> query planner look like if we took that approach?
...
> Instead, we should try to find ways of making the performance more
> transparent. We already have some features for this, but maybe more
> can be done.
Exactly; for the planner we have EXPLAIN. We could try to expose GUC
switching costs that way.
Or maybe users can start thinking of search_path as a performance-
related setting to be careful with.
Or we could try harder to optimize the switching costs so that it's not
so bad. I just started and I already saw some nice speedups; with a few
of the easy fixes done, the remaining opportunities should be more
visible in the profiler.
Regards,
Jeff Davis
