What other approach? Not using IN: the IN operator is converted to "=
any(array)" by the postgres parser:
=# explain select * from x where id in (1,2,3,4,5); QUERY PLAN ------------------------------------------------------------ Seq Scan on x (cost=0.00..6.58 rows=5 width=51) Filter: (id = ANY ('{1,2,3,4,5}'::integer[]))
It is true that this can be very inefficient for long lists, I've experimented it myself several times, but it's not something you can change at driver level: creating a temp table to join on can be faster even for not very long lists.
-- Daniele
This is the approach (and it does involve very long lists):
Instead of writing = any(array[1,2,3,4]), they wrote = any(values (1), (2), (3), (4), )
and somehow that works more quickly.
Would it be possible to make a python list subclass that converts itself to "values ( ... )" rather than to "array[ ... ]"? I imagine that this might be useful for these gigantic lists.
