adb <adb@Beast.COM> writes:
> If I have a table with a key column stored as text and
> another table with a key column stored as an int4 and
> I join the two by casting the in4 column to text, will the existing
> index on the int4 key be used?
Nope. Indexes are associated with a particular datatype and only work
for comparison operators of that datatype. The index on the first
table's text column could possibly be used in this scenario, but not
the one on the int4 column.
regards, tom lane