Comment 10 for bug 1719333

Reviewed: https://review.openstack.org/507930
Committed: https://git.openstack.org/cgit/openstack/heat/commit/?id=ab46fae9cf386b9578df4dd8ff35d68b281c7c0c
Submitter: Jenkins
Branch: stable/pike

commit ab46fae9cf386b9578df4dd8ff35d68b281c7c0c
Author: Zane Bitter <email address hidden>
Date: Mon Sep 25 10:53:38 2017 -0400

    Speed up show-stack with outputs in legacy path

    When we show a stack including the outputs, we calculate all of the
    resource attributes that are referenced anywhere in the stack. In
    convergence, these are either already cached (and therefore fast) or need
    to be cached (and therefore the initial slowness will pay off in future).
    This isn't the case in the legacy path though, since we are not doing
    caching of attributes in the database in that path. So this is
    unnecessarily calculating all of the referenced attribute values, which are
    potentially very slow to get.

    For legacy stacks, only calculate the attribute values needed to show the
    outputs.

    Change-Id: I35800c7f87b58daf05cbabd05bcbcd75d0c0fadb
    Partial-Bug: #1719333
    (cherry picked from commit 49d833f9aca351102bb1c9140231b809d8b4c519)