> This SELECT causes a sequention scan 'cause your index
> is not HASH type, but likely a BTREE one.
> BTREE index is to interval searches (station = 'SAMI4%')
> not precise searchs. (station = 'SAMI4').
In Postgres, the hash index is slow and inefficient (it's a bit better
in7.3), and I believe btree is generally recommended over hash even for '='
instances.
Chris