Re: Add connection active, idle time to pg_stat_activity

Hello,

thanks for the helpful review. I have incorporated most of the
suggestions into the patch. I have also rebased and tested the patch
on top of the current master (2cd2569c72b89200).

> + int64 active_time_diff = 0;
> + int64 transaction_idle_time_diff = 0;
>
> I think here we can use only a single variable say "state_time_diff" for
> example, as later only one of those two is incremented anyway.

I have written it this way to avoid cluttering the critical section
between PGSTAT_(BEGIN|END)_WRITE_ACTIVITY.
With two variable one can leave only actual increments in the section
and check conditions / call TimestampDifference outside of it.

Regards,
Sergey