Indexing Null Values in PostgreSQL

Question

I have a query of the form:

select m.id from mytable m
left outer join othertable o on o.m_id = m.id
    and o.col1 is not null and o.col2 is not null and o.col3         


        

Answer 1

Did you try to create a combined index on othertable(m_id, col1, col2, col3)?

You should also check the execution plan (using EXPLAIN) rather than checking the system tables for the index usage.

PostgreSQL 9.0 (currently in beta) will be able to use and index for a IS NULL condition. That feature got postponed