Merge branch 'indexes-for-recent-push-events' into 'master'

Add missing index for getting recent push events

See merge request gitlab-org/gitlab-ce!14273

db/migrate/20170914135630_add_index_for_recent_push_events.rb

+# See http://doc.gitlab.com/ce/development/migration_style_guide.html
+# for more information on how to write migrations for GitLab.
+
+class AddIndexForRecentPushEvents < ActiveRecord::Migration
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+
+  disable_ddl_transaction!
+
+  def up
+    add_concurrent_index_if_not_present(
+      :merge_requests,
+      [:source_project_id, :source_branch]
+    )
+
+    remove_concurrent_index_if_present(:merge_requests, :source_project_id)
+  end
+
+  def down
+    add_concurrent_index_if_not_present(:merge_requests, :source_project_id)
+
+    remove_concurrent_index_if_present(
+      :merge_requests,
+      [:source_project_id, :source_branch]
+    )
+  end
+
+  def add_concurrent_index_if_not_present(table, columns)
+    return if index_exists?(table, columns)
+
+    add_concurrent_index(table, columns)
+  end
+
+  def remove_concurrent_index_if_present(table, columns)
+    return unless index_exists?(table, columns)
+
+    remove_concurrent_index(table, columns)
+  end
+end

db/schema.rb

@@ -11,7 +11,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 20170913131410) do
+ActiveRecord::Schema.define(version: 20170914135630) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -892,7 +892,7 @@ ActiveRecord::Schema.define(version: 20170913131410) do
   add_index "merge_requests", ["head_pipeline_id"], name: "index_merge_requests_on_head_pipeline_id", using: :btree
   add_index "merge_requests", ["milestone_id"], name: "index_merge_requests_on_milestone_id", using: :btree
   add_index "merge_requests", ["source_branch"], name: "index_merge_requests_on_source_branch", using: :btree
-  add_index "merge_requests", ["source_project_id"], name: "index_merge_requests_on_source_project_id", using: :btree
+  add_index "merge_requests", ["source_project_id", "source_branch"], name: "index_merge_requests_on_source_project_id_and_source_branch", using: :btree
   add_index "merge_requests", ["target_branch"], name: "index_merge_requests_on_target_branch", using: :btree
   add_index "merge_requests", ["target_project_id", "iid"], name: "index_merge_requests_on_target_project_id_and_iid", unique: true, using: :btree
   add_index "merge_requests", ["title"], name: "index_merge_requests_on_title", using: :btree