I got rid of __len__ on DecoratedResultSet. Instead, I added IHasMilestones.has_milestones, since this is what len() was being used to test for, and a database count is much more intensive than finding a single unsorted matching row.

I made the changes to to the db function, and I discovered why my configuration in security.cfg wasn't granting execute to public. It expects me to specify "timestamp without time zone" instead of just "timestamp". A GRANT statement with just "timestamp" works, so it must just be the introspection that security.py does to figure out whether it is dealing with a function or a table.

I have included a new full diff below, since it is less confusing than the incremental diff and not much bigger.

-Edwin


=== added file 'database/schema/patch-2208-01-0.sql'
--- database/schema/patch-2208-01-0.sql	1970-01-01 00:00:00 +0000
+++ database/schema/patch-2208-01-0.sql	2010-08-19 17:15:22 +0000
@@ -0,0 +1,9 @@
+-- Copyright 2010 Canonical Ltd.  This software is licensed under the
+-- GNU Affero General Public License version 3 (see the file LICENSE).
+SET client_min_messages=ERROR;
+
+CREATE INDEX milestone_dateexpected_name_sort
+ON Milestone
+USING btree (milestone_sort_key(dateexpected, name));
+
+INSERT INTO LaunchpadDatabaseRevision VALUES (2208, 01, 0);

=== modified file 'database/schema/security.cfg'
--- database/schema/security.cfg	2010-08-10 05:49:16 +0000
+++ database/schema/security.cfg	2010-08-19 23:52:51 +0000
@@ -17,6 +17,7 @@
 public.person_sort_key(text, text)         = EXECUTE
 public.calculate_bug_heat(integer)         = EXECUTE
 public.debversion_sort_key(text)           = EXECUTE
+public.milestone_sort_key(timestamp without time zone, text) = EXECUTE
 public.null_count(anyarray)                = EXECUTE
 public.valid_name(text)                    = EXECUTE
 public.valid_bug_name(text)                = EXECUTE

=== modified file 'database/schema/trusted.sql'
--- database/schema/trusted.sql	2010-08-06 09:32:02 +0000
+++ database/schema/trusted.sql	2010-08-19 19:50:52 +0000
@@ -1705,3 +1705,30 @@
 
     return int(total_heat)
 $$;
+
+-- This function is not STRICT, since it needs to handle
+-- dateexpected when it is NULL.
+CREATE OR REPLACE FUNCTION milestone_sort_key(
+    dateexpected timestamp, name text)
+    RETURNS text
+AS $_$
+    # If this method is altered, then any functional indexes using it
+    # need to be rebuilt.
+    import re
+    import datetime
+
+    date_expected, name = args
+
+    def substitude_filled_numbers(match):
+        return match.group(0).zfill(5)
+
+    name = re.sub(u'\d+', substitude_filled_numbers, name)
+    if date_expected is None:
+        # NULL dates are considered to be in the future.
+        date_expected = datetime.datetime(datetime.MAXYEAR, 1, 1)
+    return '%s %s' % (date_expected, name)
+$_$
+LANGUAGE plpythonu IMMUTABLE;
+
+COMMENT ON FUNCTION milestone_sort_key(timestamp, text) IS
+'Sort by the Milestone dateexpected and name. If the dateexpected is NULL, then it is converted to a date far in the future, so it will be sorted as a milestone in the future.';

=== modified file 'lib/lp/registry/browser/__init__.py'
--- lib/lp/registry/browser/__init__.py	2010-06-12 03:37:58 +0000
+++ lib/lp/registry/browser/__init__.py	2010-08-19 23:22:43 +0000
@@ -76,7 +76,7 @@
     @property
     def milestone_table_class(self):
         """The milestone table will be unseen if there are no milestones."""
-        if len(self.context.all_milestones) > 0:
+        if self.context.has_milestones:
             return 'listing'
         else:
             # The page can remove the 'unseen' class to make the table

=== modified file 'lib/lp/registry/browser/configure.zcml'
--- lib/lp/registry/browser/configure.zcml	2010-07-16 16:58:55 +0000
+++ lib/lp/registry/browser/configure.zcml	2010-08-19 17:00:32 +0000
@@ -1655,6 +1655,13 @@
     </browser:pages>
     <browser:page
         for="lp.registry.interfaces.productseries.IProductSeries"
+        class="lp.registry.browser.productseries.ProductSeriesDetailedDisplayView"
+        template="../templates/productseries-detailed-display.pt"
+        facet="overview"
+        permission="zope.Public"
+        name="+detailed-display"/>
+    <browser:page
+        for="lp.registry.interfaces.productseries.IProductSeries"
         class="lp.registry.browser.productseries.ProductSeriesRdfView"
         facet="overview"
         permission="zope.Public"

=== modified file 'lib/lp/registry/browser/productseries.py'
--- lib/lp/registry/browser/productseries.py	2010-08-03 12:41:29 +0000
+++ lib/lp/registry/browser/productseries.py	2010-08-19 17:07:50 +0000
@@ -10,6 +10,7 @@
     'ProductSeriesBreadcrumb',
     'ProductSeriesBugsMenu',
     'ProductSeriesDeleteView',
+    'ProductSeriesDetailedDisplayView',
     'ProductSeriesEditView',
     'ProductSeriesFacets',
     'ProductSeriesFileBugRedirect',
@@ -436,6 +437,19 @@
         return None
 
 
+class ProductSeriesDetailedDisplayView(ProductSeriesView):
+
+    @cachedproperty
+    def latest_milestones(self):
+        # Convert to list to avoid the query being run multiple times.
+        return list(self.context.milestones[:12])
+
+    @cachedproperty
+    def latest_releases(self):
+        # Convert to list to avoid the query being run multiple times.
+        return list(self.context.releases[:12])
+
+
 class ProductSeriesUbuntuPackagingView(LaunchpadFormView):
 
     schema = IPackaging

=== modified file 'lib/lp/registry/browser/tests/productseries-views.txt'
--- lib/lp/registry/browser/tests/productseries-views.txt	2010-07-30 20:00:59 +0000
+++ lib/lp/registry/browser/tests/productseries-views.txt	2010-08-19 17:00:32 +0000
@@ -307,7 +307,7 @@
 specifications that will be unassigned, and release files that will be
 deleted are available.
 
-    >>> view.milestones
+    >>> list(view.milestones)
     []
     >>> view.bugtasks
     []

=== modified file 'lib/lp/registry/interfaces/milestone.py'
--- lib/lp/registry/interfaces/milestone.py	2010-04-24 11:19:53 +0000
+++ lib/lp/registry/interfaces/milestone.py	2010-08-20 02:51:36 +0000
@@ -225,6 +225,8 @@
     """An interface for classes providing milestones."""
     export_as_webservice_entry()
 
+    has_milestones = Bool(title=_("Whether the object has any milestones."))
+
     milestones = exported(
         CollectionField(
             title=_("The visible and active milestones associated with this "

=== modified file 'lib/lp/registry/model/milestone.py'
--- lib/lp/registry/model/milestone.py	2010-08-02 02:13:52 +0000
+++ lib/lp/registry/model/milestone.py	2010-08-20 04:00:43 +0000
@@ -21,8 +21,13 @@
 from sqlobject import (
     AND, BoolCol, DateCol, ForeignKey, SQLMultipleJoin, SQLObjectNotFound,
     StringCol)
-from storm.locals import And, Store
-
+
+
+from storm.expr import And
+from storm.store import Store
+
+
+from canonical.cachedproperty import cachedproperty
 from canonical.database.sqlbase import SQLBase, sqlvalues
 from canonical.launchpad.webapp.sorting import expand_numbers
 from lp.app.errors import NotFoundError
@@ -63,6 +68,9 @@
 class HasMilestonesMixin:
     implements(IHasMilestones)
 
+    _milestone_order = (
+        'milestone_sort_key(Milestone.dateexpected, Milestone.name) DESC')
+
     def _getMilestoneCondition(self):
         """Provides condition for milestones and all_milestones properties.
 
@@ -74,11 +82,15 @@
             "Unexpected class for mixin: %r" % self)
 
     @property
+    def has_milestones(self):
+        return self.all_milestones.any() is not None
+
+    @property
     def all_milestones(self):
         """See `IHasMilestones`."""
         store = Store.of(self)
         result = store.find(Milestone, self._getMilestoneCondition())
-        return sorted(result, key=milestone_sort_key, reverse=True)
+        return result.order_by(self._milestone_order)
 
     @property
     def milestones(self):
@@ -87,7 +99,7 @@
         result = store.find(Milestone,
                             And(self._getMilestoneCondition(),
                                 Milestone.active == True))
-        return sorted(result, key=milestone_sort_key, reverse=True)
+        return result.order_by(self._milestone_order)
 
 
 class Milestone(SQLBase, StructuralSubscriptionTargetMixin, HasBugsBase):

=== modified file 'lib/lp/registry/model/projectgroup.py'
--- lib/lp/registry/model/projectgroup.py	2010-08-02 02:13:52 +0000
+++ lib/lp/registry/model/projectgroup.py	2010-08-20 03:46:39 +0000
@@ -54,7 +54,7 @@
 from lp.services.worlddata.model.language import Language
 from lp.registry.model.mentoringoffer import MentoringOffer
 from lp.registry.model.milestone import (
-    Milestone, ProjectMilestone, milestone_sort_key)
+    Milestone, ProjectMilestone)
 from lp.registry.model.announcement import MakesAnnouncements
 from lp.registry.model.pillar import HasAliasMixin
 from lp.registry.model.product import Product
@@ -381,10 +381,25 @@
         result.group_by(Milestone.name)
         if only_active:
             result.having('BOOL_OR(Milestone.active) = TRUE')
-        milestones = shortlist(
+        # MIN(Milestone.dateexpected) has to be used to match the
+        # aggregate function in the `columns` variable.
+        result.order_by(
+            'milestone_sort_key(MIN(Milestone.dateexpected), Milestone.name) '
+            'DESC')
+        return shortlist(
             [ProjectMilestone(self, name, dateexpected, active)
              for name, dateexpected, active in result])
-        return sorted(milestones, key=milestone_sort_key, reverse=True)
+
+    @property
+    def has_milestones(self):
+        """See `IHasMilestones`."""
+        store = Store.of(self)
+        result = store.find(
+            Milestone.id,
+            And(Milestone.product == Product.id,
+                Product.project == self,
+                Product.active == True))
+        return result.any() is not None
 
     @property
     def milestones(self):

=== modified file 'lib/lp/registry/stories/productseries/xx-productseries-series.txt'
--- lib/lp/registry/stories/productseries/xx-productseries-series.txt	2010-05-24 20:23:19 +0000
+++ lib/lp/registry/stories/productseries/xx-productseries-series.txt	2010-08-19 17:00:32 +0000
@@ -29,7 +29,7 @@
     >>> series_trunk = find_tag_by_id(content, 'series-trunk')
     >>> print extract_text(series_trunk)
     trunk series Focus of Development
-    Milestones: 1.0    Releases: 0.9.2, 0.9.1, 0.9
+    Latest milestones: 1.0    Latest releases: 0.9.2, 0.9.1, 0.9
     Bugs targeted: None
     Blueprints targeted: 1 Unknown
     The "trunk" series represents the primary line of development rather ...
@@ -46,7 +46,7 @@
     >>> series_1_0 = find_tag_by_id(content, 'series-1-0')
     >>> print extract_text(series_1_0)
     1.0 series Active Development
-    Releases: 1.0.0
+    Latest releases: 1.0.0
     Bugs targeted: 1 New
     Blueprints targeted: None
     The 1.0 branch of the Mozilla web browser. Currently, this is the ...

=== modified file 'lib/lp/registry/templates/object-milestones.pt'
--- lib/lp/registry/templates/object-milestones.pt	2009-11-07 00:49:26 +0000
+++ lib/lp/registry/templates/object-milestones.pt	2010-08-20 04:02:09 +0000
@@ -28,7 +28,7 @@
   <tal:milestones define="milestones context/all_milestones">
     <table id="milestones" class="listing"
       tal:define="has_series context/series|nothing"
-      tal:condition="milestones">
+      tal:condition="context/has_milestones">
       <thead>
         <tr>
           <th>Version</th>
@@ -45,7 +45,7 @@
       </tbody>
     </table>
 
-    <tal:no-milestones condition="not: milestones">
+    <tal:no-milestones condition="not: context/has_milestones">
       <p>There are no milestones associated with
         <span tal:replace="context/title" />
       </p>

=== modified file 'lib/lp/registry/templates/productseries-macros.pt'
--- lib/lp/registry/templates/productseries-macros.pt	2010-05-24 20:23:19 +0000
+++ lib/lp/registry/templates/productseries-macros.pt	2010-08-19 17:00:32 +0000
@@ -4,48 +4,6 @@
   xmlns:i18n="http://xml.zope.org/namespaces/i18n"
   omit-tag="">
 
-<metal:detailed_display define-macro="detailed_display">
-  <tal:comment replace="nothing">
-    This macro expects two variables to be defined:
-      - 'series': The ProductSeries
-      - 'is_focus': A boolean saying whether this is the series in which
-                    development is focused.
-  </tal:comment>
-
-  <strong><a tal:attributes="href series/fmt:url"
-             tal:content="series/name" >
-      1.0
-    </a> series
-  </strong>
-  <em tal:condition="is_focus">Focus of Development</em>
-  <em tal:condition="not: is_focus" tal:content="series/status/title">
-    This series' status
-  </em>
-  <div>
-    <tal:milestones condition="series/milestones">
-      Milestones:
-      <tal:milestone repeat="milestone series/milestones">
-        <a tal:attributes="href milestone/fmt:url" tal:content="milestone/name"
-          >name</a><tal:comma condition="not:repeat/milestone/end">,</tal:comma>
-      </tal:milestone>
-    </tal:milestones>
-    <tal:release repeat="release series/releases">
-      <tal:release-start condition="repeat/release/start">
-        <tal:comment condition="nothing">
-          Releases may be a list or an resultset. We cannot easily know if there
-          releases until the first one is returned.
-        </tal:comment>
-        <tal:space condition="series/milestones"> &nbsp &nbsp </tal:space>
-        Releases:
-      </tal:release-start>
-      <a tal:attributes="href release/fmt:url" tal:content="release/version"
-        >version</a><tal:comma condition="not:repeat/release/end">,</tal:comma>
-    </tal:release>
-  </div>
-  <metal:extra define-slot="extra" />
-</metal:detailed_display>
-
-
 <metal:branch_display define-macro="branch_display">
   <tal:comment condition="nothing">
     This macro expects two variables to be defined:

=== modified file 'lib/lp/registry/templates/productseries-status.pt'
--- lib/lp/registry/templates/productseries-status.pt	2009-07-21 18:17:49 +0000
+++ lib/lp/registry/templates/productseries-status.pt	2010-08-19 17:00:32 +0000
@@ -8,8 +8,7 @@
     is_focus context/is_development_focus;
     spec_count_status view/specification_status_counts;"
   >
-  <metal:series use-macro="series/@@+macros/detailed_display">
-    <div metal:fill-slot="extra">
+  <div tal:replace="structure context/@@+detailed-display"/>
       <div>
         <tal:not-obsolete
           condition="not: view/is_obsolete"
@@ -42,6 +41,4 @@
       <tal:summary
         condition="series/summary"
         content="structure context/summary/fmt:text-to-html" />
-    </div>
-  </metal:series>
 </div>