> database=> explain select date_trunc('hour', time),count(*) as total from
> test where p1=53 and time > now() - interval '24 hours' group by
> date_trunc order by date_trunc ;
1. Use CURRENT_TIMESTAMP (which is considered a constant by the planner)
instead of now()
2. Create a multicolumn index on (p1,time) or (time,p1) whichever works
better