Postgres NOT IN performance

Question

Any ideas how to speed up this query?

Input

EXPLAIN SELECT entityid FROM entity e

LEFT JOIN level1entity l1 ON l1.level1id = e.level1_level1id
LEFT         


        

Answer 1

You might get a better result if you can rewrite the query to use a hash anti-join.

Something like:

with exclude_list as (
  select unnest(string_to_array('1377776,1377792,1377793,1377794,1377795, ...',','))::integer entity_id)
select entity_id
from   entity left join exclude_list on entity.entity_id = exclude_list.entity_id
where  exclude_list.entity_id is null;