On Mon, 12 May 2025, 05:08 Andrei Lepikhov, <lepihov@xxxxxxxxx> wrote:
Thanks for this puzzle!
I suppose, in case generic planning is much faster than custom one,
there are two candidates exist:
1. Touching the index during planning causes too much overhead - see
get_actual_variable_range
2. You have a massive default_statistics_target for a table involved.
This is just an artifact of the fact that runtime pruning is not factored into the costs. Note the cost of the generic plan. The plan_cache_mode GUC is about the only way to overrule the choice to use the custom plan.
David
