Support dropping indexes concurrently in Postgres

See http://www.postgresql.org/docs/9.4/static/sql-dropindex.html
for more details.

3 files changed, 12 insertions, 7 deletions

diff --git a/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb b/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
index a30945d0ee..4653904105 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
@@ -607,10 +607,7 @@ module ActiveRecord
       #   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
 
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb b/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb
index a3fc8fbc51..26ef23a0d9 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb
@@ -447,8 +447,15 @@ module ActiveRecord
           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
diff --git a/activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb b/activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb
index 358039723f..24fc67938d 100644
--- a/activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb
@@ -375,7 +375,8 @@ module ActiveRecord
         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