1 files changed, 41 insertions, 58 deletions

diff --git a/activerecord/lib/active_record/connection_adapters/mysql/database_statements.rb b/activerecord/lib/active_record/connection_adapters/mysql/database_statements.rb
index 13c9b6cbd9..78e7181266 100644
--- a/activerecord/lib/active_record/connection_adapters/mysql/database_statements.rb
+++ b/activerecord/lib/active_record/connection_adapters/mysql/database_statements.rb
@@ -13,19 +13,6 @@ module ActiveRecord
           result
         end
 
-        # Returns a record hash with the column names as keys and column values
-        # as values.
-        def select_one(arel, name = nil, binds = [])
-          arel, binds = binds_from_relation(arel, binds)
-          @connection.query_options.merge!(as: :hash)
-          select_result(to_sql(arel, binds), name, binds) do |result|
-            @connection.next_result while @connection.more_results?
-            result.first
-          end
-        ensure
-          @connection.query_options.merge!(as: :array)
-        end
-
         # Returns an array of arrays containing the field values.
         # Order is the same as that returned by +columns+.
         def select_rows(sql, name = nil, binds = [])
@@ -37,16 +24,14 @@ module ActiveRecord
 
         # Executes the SQL statement in the context of this connection.
         def execute(sql, name = nil)
-          if @connection
-            # make sure we carry over any changes to ActiveRecord::Base.default_timezone that have been
-            # made since we established the connection
-            @connection.query_options[:database_timezone] = ActiveRecord::Base.default_timezone
-          end
+          # make sure we carry over any changes to ActiveRecord::Base.default_timezone that have been
+          # made since we established the connection
+          @connection.query_options[:database_timezone] = ActiveRecord::Base.default_timezone
 
           super
         end
 
-        def exec_query(sql, name = 'SQL', binds = [], prepare: false)
+        def exec_query(sql, name = "SQL", binds = [], prepare: false)
           if without_prepared_statement?(binds)
             execute_and_free(sql, name) do |result|
               ActiveRecord::Result.new(result.fields, result.to_a) if result
@@ -58,7 +43,7 @@ module ActiveRecord
           end
         end
 
-        def exec_delete(sql, name, binds)
+        def exec_delete(sql, name = nil, binds = [])
           if without_prepared_statement?(binds)
             execute_and_free(sql, name) { @connection.affected_rows }
           else
@@ -67,58 +52,56 @@ module ActiveRecord
         end
         alias :exec_update :exec_delete
 
-        protected
-
-        def last_inserted_id(result)
-          @connection.last_id
-        end
-
         private
 
-        def select_result(sql, name = nil, binds = [])
-          if without_prepared_statement?(binds)
-            execute_and_free(sql, name) { |result| yield result }
-          else
-            exec_stmt_and_free(sql, name, binds, cache_stmt: true) { |_, result| yield result }
+          def last_inserted_id(result)
+            @connection.last_id
           end
-        end
 
-        def exec_stmt_and_free(sql, name, binds, cache_stmt: false)
-          if @connection
+          def select_result(sql, name = nil, binds = [])
+            if without_prepared_statement?(binds)
+              execute_and_free(sql, name) { |result| yield result }
+            else
+              exec_stmt_and_free(sql, name, binds, cache_stmt: true) { |_, result| yield result }
+            end
+          end
+
+          def exec_stmt_and_free(sql, name, binds, cache_stmt: false)
             # make sure we carry over any changes to ActiveRecord::Base.default_timezone that have been
             # made since we established the connection
             @connection.query_options[:database_timezone] = ActiveRecord::Base.default_timezone
-          end
 
-          type_casted_binds = binds.map { |attr| type_cast(attr.value_for_database) }
+            type_casted_binds = type_casted_binds(binds)
 
-          log(sql, name, binds) do
-            if cache_stmt
-              cache = @statements[sql] ||= {
-                stmt: @connection.prepare(sql)
-              }
-              stmt = cache[:stmt]
-            else
-              stmt = @connection.prepare(sql)
-            end
-
-            begin
-              result = stmt.execute(*type_casted_binds)
-            rescue Mysql2::Error => e
+            log(sql, name, binds, type_casted_binds) do
               if cache_stmt
-                @statements.delete(sql)
+                cache = @statements[sql] ||= {
+                  stmt: @connection.prepare(sql)
+                }
+                stmt = cache[:stmt]
               else
-                stmt.close
+                stmt = @connection.prepare(sql)
+              end
+
+              begin
+                result = ActiveSupport::Dependencies.interlock.permit_concurrent_loads do
+                  stmt.execute(*type_casted_binds)
+                end
+              rescue Mysql2::Error => e
+                if cache_stmt
+                  @statements.delete(sql)
+                else
+                  stmt.close
+                end
+                raise e
               end
-              raise e
-            end
 
-            ret = yield stmt, result
-            result.free if result
-            stmt.close unless cache_stmt
-            ret
+              ret = yield stmt, result
+              result.free if result
+              stmt.close unless cache_stmt
+              ret
+            end
           end
-        end
       end
     end
   end