Re: Execution plan does not use index

[Michael Lewis <mlewis@xxxxxxxxxxx>]

On Tue, Nov 10, 2020, 3:24 PM Peter Coppens <peter.coppens@xxxxxxxxxxx> wrote:

Index is not used for the subquery

explain 

select mv_inner.*

  from measurement_value AS mv_inner

  where mv_inner.timestamp > '2020-11-06'::timestamp - interval '1 day' and mv_inner.timestamp < '2020-11-07'::timestamp + interval '1 day'

offset 0

==>

Seq Scan on measurement_value mv_inner (cost=0.00..7175777.00 rows=1219616 width=1006)
  Filter: (("timestamp" > '2020-11-05 00:00:00'::timestamp without time zone) AND ("timestamp" < '2020-11-08 00:00:00'::timestamp without time zone))

Curious, how accurate is that row count of 1.2 million records for 3 days? How many total records in the table? If you disable sequential scan, does it choose the index and what cost does it show?