[flooo]

I'm surprised there is no mention of Postgres' Genetic Query Optimizer (GEQO) here. It kicks in when there is a large number of joins and reduces query planning time at the cost of query execution time.

Another post in this thread mentions adaptive query planning and mistakenly imply that the GEQO is a module for this. My hands have been itching to look into experimenting on some improvements on the GEQO, specifically by improving the genetic algorithms used. When there are many similar queries, so in the adaptive query planning setting, one could also use reinforcement learning to improve query planning over time.