About what you said, that some settings can be configured by Tablespace?
I have already seen this in IBM DB2, but in Postgresql as far as I know, for example the Random_page_cost and Seq_page_cost parameters are configured for the Integer Database and not for Tablespace, ok?.
You or someone can tell me if cost parameters can be configured by Tablespace, this would be useful for me, thinking of a server that has hybrid storage environment (HDD x SSDs), I could leave some in a tablespace with HDD adapted settings and the same way for when I have an SSD disk.