Re: [COMMITTERS] pgsql: Provide much better wait information in pg_stat_activity.

On Thu, Mar 10, 2016 at 8:31 PM, Joel Jacobson <joel(at)trustly(dot)com> wrote:
> This is an excellent feature, thanks!
> But can we please keep the old boolean waiting column?
> I see no reason to break backward-compatibility. Or maybe I'm missing something.

Well, this was discussed. If we keep the Boolean "waiting" column, then either:

1. We make it true only for heavyweight lock waits, and false for
other kinds of waits. That's pretty strange.
2. We make it true for all kinds of waits that we now know how to
report. That still breaks compatibility.

I do understand that changing this is backward-incompatible and a lot
of people are going to have to update their monitoring tools. But I
think that's the best alternative. If we choose option #1, we're
going to be saddled with a weird backward-compatibility column
forever, and ten years from now we'll be explaining that even if
waiting = false you might still be waiting depending on the value of
some other column. If we choose option #2, it won't be
backward-compatible and some people's queries will still break, just
less obviously. Neither of those things seems very appealing.

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company