Re: add queryEnv to ExplainOneQuery_hook

On Wed, Mar 14, 2018 at 05:36:26PM +1300, Thomas Munro wrote:
> Hmm. I suppose we could have invented a new extended hook with a
> different name and back-patched it so that PG10 would support both.
> Then binary compatibility with existing compiled extensions wouldn't
> be affected AFAICS, but you could use the new extended hook in (say)
> 10.4 or higher. Then for PG11 (or later) we could remove the old hook
> and just keep the new one. I suppose that option is still technically
> open to us, though I'm not sure of the committers' appetite for messing
> with back branches like that.

The interactions between both hooks would not be difficult to define: if
the original hook is not defined, just do not trigger the second. Still
that's too late for v10, so I would rather let it go. New features are
not backpatched.
--
Michael