Sorry, I didn't notice the SELECT * and I said something stupid...
However my reasoning should be still valid: I mean, PG could find the few relevant rows (there's a LIMIT 30) using ONLY the index. It has all the information required inside the index! Then it can simply access to that rows on disk... It cannot take ~1 minute to access a few rows on disk (max 30 rows, actual 0 rows).
Marco Colli <collimarco91@gmail.com> writes: > As you can see it is a *index scan* and not an *index only* scan... I don't > understand why. The index includes all the fields used by the query... so > an index only scan should be possible.
Huh? The query is "select * from ...", so it retrieves *all* columns of the table.