Can multi indexing speed up "AND" of comparisons?
A multi-column index cannot be used for both conditions. For example, an index on (a, b) could be used for the condition a &gt; 30, but not for b &lt; 20.

If one of the conditions alone is selective enough and the other does not reduce the result set considerably, just create an index for that condition.

If you need index support for both conditions because neither of them is selective enough on its own, create two indexes, one for each condition. Then PostgreSQL can use a bitmap index scan on both indexes and a &ldquo;bitmap or&rdquo; to combine the results.