On 7/1/2024 06:54, Tomas Vondra wrote:
It's an interesting are for experiments, no doubt about it. And if you choose to explore it, that's fine. But it's better to be aware it may not end with a commit. For the multi-dimensional case, I propose we first try to experiment with the various algorithms, and figure out what works etc. Maybe implementing them in python or something would be easier than C.
Curiously, trying to utilize extended statistics for some problematic cases, I am experimenting with auto-generating such statistics by definition of indexes [1]. Doing that, I wanted to add some hand-made statistics like a multidimensional histogram or just a histogram which could help to perform estimation over a set of columns/expressions. I realized that current hooks get_relation_stats_hook and get_index_stats_hook are insufficient if I want to perform an estimation over a set of ANDed quals on different columns. In your opinion, is it possible to add a hook into the extended statistics to allow for an extension to propose alternative estimation?
[1] https://github.com/danolivo/pg_index_stats -- regards, Andrei Lepikhov Postgres Professional
