Re: [HACKERS] Date operations - Mailing list pgsql-hackers

> Question 3:
> Because this query gets hit a lot, would it make sense to create an
> index
>  CREATE INDEX tbl_robot_logs_at_age_idx ON tbl_robot_logs
>   ( AGE(at) );

Nope, since "age" is calculated from "now", which is alway changing.
You can't make a useful index on a non-constant expression or
function.
                       - Tom