You're essentially asking for a random sample of data that is not currently in memory. You're not going to get that without some I/O.
No, that sounds reasonable enough. But do you agree with the statement that my query will just get slower and slower over time as the number of posts increases while the part having status = 1 is constant? (Therefore, as the relevant fraction becomes smaller over time, the "Filter: status = 1" operation becomes slower.)
---------------------------(end of broadcast)--------------------------- TIP 6: explain analyze is your friend
