Will Hartung schrieb am 31.05.2019 um 00:11:
> If you have 10M rows with a “STATUS” column of 1 or 2, and an index
> on that column, then you have a 2 node index with a bazillion row
> pointers. Some systems (I can’t speak to PG in this regard)
> degenerate in this kind of use case since the index is more or less
> designed to work great in unique identifiers than low cardinality
> values. The representation of large record pointer lists may just not
> be handled well as edge cases.
What I very often do in theses cases is to create two partial indexes:
One with "WHERE status = 1" and another with "WHERE STATUS = 2" including
_another_ column in the index that I usually use together with the status
column in the queries.