feat: optimise latest_pact_consumer_version_orders

Author: bethesque

db/ddl_statements/latest_pact_consumer_version_orders.rb

@@ -0,0 +1,13 @@
+def latest_pact_consumer_version_orders_v1(connection = nil)
+  "select provider_id, consumer_id, max(consumer_version_order) as latest_consumer_version_order
+  from all_pact_publications
+  group by provider_id, consumer_id"
+end
+
+def latest_pact_consumer_version_orders_v2(connection = nil)
+  view = Sequel.as(:latest_pact_publication_ids_for_consumer_versions, :lp)
+  connection.from(view)
+    .select_group(:consumer_id, :provider_id)
+    .select_append{ max(order).as(latest_consumer_version_order) }
+    .join(:versions, { Sequel[:lp][:consumer_version_id] => Sequel[:cv][:id]}, { table_alias: :cv} )
+end

db/migrations/20180722_recreate_views.rb

@@ -35,9 +35,6 @@
         )
 
     create_or_replace_view(:latest_pact_consumer_version_orders,
-      "select provider_id, consumer_id, max(consumer_version_order) as latest_consumer_version_order
-      from all_pact_publications
-      group by provider_id, consumer_id"
-    )
+      latest_pact_consumer_version_orders_v1(self))
   end
 end

db/migrations/20191029_optimise_latest_pact_cv_orders.rb

@@ -0,0 +1,13 @@
+require_relative '../ddl_statements'
+
+Sequel.migration do
+  up do
+    create_or_replace_view(:latest_pact_consumer_version_orders,
+      latest_pact_consumer_version_orders_v2(self))
+  end
+
+  down do
+    create_or_replace_view(:latest_pact_consumer_version_orders,
+      latest_pact_consumer_version_orders_v1(self))
+  end
+end