PostgreSQL, Support for materialized views. [Dave Lee & Yves Senn]

Expand the query used in #table_exists? to include materialized views in the
kinds of relations it searches.

activerecord/CHANGELOG.md

@@ -1,3 +1,7 @@
+*   Enable support for materialized views on PostgreSQL >= 9.3.
+
+    *Dave Lee*
+
 *   The PostgreSQL adapter supports custom domains. Fixes #14305.
 
     *Yves Senn*

activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb

@@ -104,14 +104,11 @@ def table_exists?(name)
           schema, table = Utils.extract_schema_and_table(name.to_s)
           return false unless table
 
-          binds = [[nil, table]]
-          binds << [nil, schema] if schema
-
           exec_query(<<-SQL, 'SCHEMA').rows.first[0].to_i > 0
               SELECT COUNT(*)
               FROM pg_class c
               LEFT JOIN pg_namespace n ON n.oid = c.relnamespace
-              WHERE c.relkind in ('v','r')
+              WHERE c.relkind IN ('r','v','m') -- (r)elation/table, (v)iew, (m)aterialized view
               AND c.relname = '#{table.gsub(/(^"|"$)/,'')}'
               AND n.nspname = #{schema ? "'#{schema}'" : 'ANY (current_schemas(false))'}
           SQL

activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb

@@ -454,6 +454,10 @@ def supports_ranges?
         postgresql_version >= 90200
       end
 
+      def supports_materialized_views?
+        postgresql_version >= 90300
+      end
+
       def enable_extension(name)
         exec_query("CREATE EXTENSION IF NOT EXISTS \"#{name}\"").tap {
           reload_type_map

activerecord/test/cases/adapters/postgresql/view_test.rb

@@ -1,11 +1,15 @@
 require "cases/helper"
 
-class ViewTest < ActiveRecord::TestCase
-  self.use_transactional_fixtures = false
+module ViewTestConcern
+  extend ActiveSupport::Concern
+
+  included do
+    self.use_transactional_fixtures = false
+    mattr_accessor :view_type
+  end
 
   SCHEMA_NAME = 'test_schema'
   TABLE_NAME = 'things'
-  VIEW_NAME = 'view_things'
   COLUMNS = [
     'id integer',
     'name character varying(50)',
@@ -14,17 +18,19 @@ class ViewTest < ActiveRecord::TestCase
   ]
 
   class ThingView < ActiveRecord::Base
-    self.table_name = 'test_schema.view_things'
   end
 
   def setup
+    super
+    ThingView.table_name = "#{SCHEMA_NAME}.#{view_type}_things"
+
     @connection = ActiveRecord::Base.connection
     @connection.execute "CREATE SCHEMA #{SCHEMA_NAME} CREATE TABLE #{TABLE_NAME} (#{COLUMNS.join(',')})"
-    @connection.execute "CREATE TABLE #{SCHEMA_NAME}.\"#{TABLE_NAME}.table\" (#{COLUMNS.join(',')})"
-    @connection.execute "CREATE VIEW #{SCHEMA_NAME}.#{VIEW_NAME} AS SELECT id,name,email,moment FROM #{SCHEMA_NAME}.#{TABLE_NAME}"
+    @connection.execute "CREATE #{view_type.humanize} #{ThingView.table_name} AS SELECT * FROM #{SCHEMA_NAME}.#{TABLE_NAME}"
   end
 
-  teardown do
+  def teardown
+    super
     @connection.execute "DROP SCHEMA #{SCHEMA_NAME} CASCADE"
   end
 
@@ -35,7 +41,7 @@ def test_table_exists
 
   def test_column_definitions
     assert_nothing_raised do
-      assert_equal COLUMNS, columns("#{SCHEMA_NAME}.#{VIEW_NAME}")
+      assert_equal COLUMNS, columns(ThingView.table_name)
     end
   end
 
@@ -47,3 +53,15 @@ def columns(table_name)
     end
 
 end
+
+class ViewTest < ActiveRecord::TestCase
+  include ViewTestConcern
+  self.view_type = 'view'
+end
+
+if ActiveRecord::Base.connection.supports_materialized_views?
+  class MaterializedViewTest < ActiveRecord::TestCase
+    include ViewTestConcern
+    self.view_type = 'materialized_view'
+  end
+end