While working on a Postgres docker container executing some queries I noticed that my index-only scan query is hitting the heap which it shouldn't. After digging deep I found that it's the shared memory that docker allocates by default. Defaults are never enough, very interesting train of thought that I thought I’d share with you  The Blog I found that helped me find it https://blog.makandra.com/2018/11/investigating-slow-postgres-index-only-scans/