Merge lp:~cjwatson/launchpad/db-recipe-build-ordering into lp:launchpad/db-devel

[Colin Watson]

Add NULLS LAST to SourcePackageRecipe.*builds indexes.

This goes with https://code.launchpad.net/~cjwatson/launchpad/recipe-build-ordering/+merge/340534.

[William Grant (wgrant)]

review: Approve (db)

=== added file 'database/schema/patch-2209-73-1.sql'
--- database/schema/patch-2209-73-1.sql	1970-01-01 00:00:00 +0000
+++ database/schema/patch-2209-73-1.sql	2018-03-02 18:02:42 +0000
@@ -0,0 +1,18 @@
+-- Copyright 2018 Canonical Ltd.  This software is licensed under the
+-- GNU Affero General Public License version 3 (see the file LICENSE).
+
+SET client_min_messages=ERROR;
+
+DROP INDEX sourcepackagerecipebuild__recipe__started__finished__created__idx;
+DROP INDEX sourcepackagerecipebuild__recipe__started__finished__idx;
+
+CREATE INDEX sourcepackagerecipebuild__recipe__started__finished__created__idx
+    ON SourcePackageRecipeBuild (
+        recipe, GREATEST(date_started, date_finished) DESC NULLS LAST,
+        date_created DESC, id DESC);
+CREATE INDEX sourcepackagerecipebuild__recipe__started__finished__idx
+    ON SourcePackageRecipeBuild (
+        recipe, GREATEST(date_started, date_finished) DESC NULLS LAST,
+        id DESC);
+
+INSERT INTO LaunchpadDatabaseRevision VALUES (2209, 73, 1);