Merge pull request #21317 from greysteil/support-postgres-drop-index-concurrently

Support dropping indexes concurrently in Postgres

activerecord/CHANGELOG.md

+*   Support dropping indexes concurrently in Postgres.
+
+    See http://www.postgresql.org/docs/9.4/static/sql-dropindex.html for more
+    details.
+
+    *Grey Baker*
+
 *   Deprecate passing conditions to `ActiveRecord::Relation#delete_all`
     and `ActiveRecord::Relation#destroy_all`
 

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

@@ -607,10 +607,7 @@ def add_index(table_name, column_name, options = {})
       #   remove_index :accounts, name: :by_branch_party
       #
       def remove_index(table_name, options = {})
-        remove_index!(table_name, index_name_for_remove(table_name, options))
-      end
-
-      def remove_index!(table_name, index_name) #:nodoc:
+        index_name = index_name_for_remove(table_name, options)
         execute "DROP INDEX #{quote_column_name(index_name)} ON #{quote_table_name(table_name)}"
       end
 

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

@@ -447,8 +447,15 @@ def add_index(table_name, column_name, options = {}) #:nodoc:
           execute "CREATE #{index_type} INDEX #{index_algorithm} #{quote_column_name(index_name)} ON #{quote_table_name(table_name)} #{index_using} (#{index_columns})#{index_options}"
         end
 
-        def remove_index!(table_name, index_name) #:nodoc:
-          execute "DROP INDEX #{quote_table_name(index_name)}"
+        def remove_index(table_name, options = {}) #:nodoc:
+          index_name = index_name_for_remove(table_name, options)
+          algorithm =
+            if options.key?(:algorithm)
+              index_algorithms.fetch(options[:algorithm]) do
+                raise ArgumentError.new("Algorithm must be one of the following: #{index_algorithms.keys.map(&:inspect).join(', ')}")
+              end
+            end
+          execute "DROP INDEX #{algorithm} #{quote_table_name(index_name)}"
         end
 
         # Renames an index of a table. Raises error if length of new

activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb

@@ -375,7 +375,8 @@ def primary_key(table_name) #:nodoc:
         pks[0]['name']
       end
 
-      def remove_index!(table_name, index_name) #:nodoc:
+      def remove_index(table_name, options = {}) #:nodoc:
+        index_name = index_name_for_remove(table_name, options)
         exec_query "DROP INDEX #{quote_column_name(index_name)}"
       end
 

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

@@ -51,6 +51,15 @@ def test_add_index
     assert_equal expected, add_index(:people, :last_name, :unique => true, :where => "state = 'active'", :using => :gist)
   end
 
+  def test_remove_index
+    expected = %(DROP INDEX CONCURRENTLY "index_people_on_last_name")
+    assert_equal expected, remove_index(:people, name: "index_people_on_last_name", algorithm: :concurrently)
+
+    assert_raise ArgumentError do
+      add_index(:people, :last_name, algorithm: :copy)
+    end
+  end
+
   private
     def method_missing(method_symbol, *arguments)
       ActiveRecord::Base.connection.send(method_symbol, *arguments)

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

@@ -321,11 +321,11 @@ def test_dump_indexes_for_schema_multiple_schemas_in_search_path
 
   def test_with_uppercase_index_name
     @connection.execute "CREATE INDEX \"things_Index\" ON #{SCHEMA_NAME}.things (name)"
-    assert_nothing_raised { @connection.remove_index! "things", "#{SCHEMA_NAME}.things_Index"}
+    assert_nothing_raised { @connection.remove_index "things", name: "#{SCHEMA_NAME}.things_Index"}
     @connection.execute "CREATE INDEX \"things_Index\" ON #{SCHEMA_NAME}.things (name)"
 
     with_schema_search_path SCHEMA_NAME do
-      assert_nothing_raised { @connection.remove_index! "things", "things_Index"}
+      assert_nothing_raised { @connection.remove_index "things", name: "things_Index"}
     end
   end