I can see how that can be a problem. I run MySQL but other commenters said that Postgres has "schemas" which appear to be more similar to MySQL's "databases".

I can see how that can be a problem. I run MySQL but other commenters said that Postgres has "schemas" which appear to be more similar to MySQL's "databases". In the same way I thought you meant the query result cache, not the query plan cache. In my experience query planning hasn't been a significant bottleneck, but that's got to be workload dependent.