> Starting with PostgreSQL 9.6, foreign keys are also used to help with > join selectivity estimations. I see you have a suitable foreign key > from the schema you posted. You might want to add that to the list of > reasons to upgrade.
Apologies for the delay in response. I've had "PostgreSQL 9.6.3, compiled by Visual C++ build 1800, 64-bit" setup at home for a while and after importing the data across I'm still seeing the same behaviour. Even after upgrading my local install of PG to "PostgreSQL 12.2, compiled by Visual C++ build 1914, 64-bit" and I'm still seeing the same behaviour. Plans for PG12:- Query A: https://explain.depesz.com/s/zrVD Query B: https://explain.depesz.com/s/ZLWe The settings for my home setup are left at default, nothing special. Indy
