Phoenix Kiula <phoenix(dot)kiula(at)gmail(dot)com> writes:
> Just want to check why, in an UPDATE sql, the JOIN condition is not making
> use of the index?
> [ whole-table update done with a hash join ]
That's a perfectly good plan. Indexes typically help only when you want
to process just part of a table.
If you don't believe it, you can try forcing a different plan to be
chosen (see enable_hashjoin et al), but more than likely it'll be
slower.
regards, tom lane