CREATE TABLE `test_wo_keys` ( `f01` int AUTO_INCREMENT, `f02` bigint, `f03` bigint, `f04` enum('a','b'), `f05` date, `f06` int, `f07` int, `f08` double, `f09` int, `f10` bigint, `f11` double, `f12` enum('a','b','c','d','e'), `f13` int, `f14` int, `f15` varchar(255), `f16` int, `f17` int, `f18` int, `f19` double, `f20` double, `f21` double, `f22` double, `f23` double, `f24` tinyint, `f25` double, `f26` double, `f27` double, `f28` double, `f29` int unsigned, `f30` int unsigned, `f31` bigint, `f32` int unsigned, `f33` bigint, `f34` int unsigned, `f35` int unsigned, PRIMARY KEY `f01` (`f01`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1; show status like '%merge_buffers%'; Variable_name Value Innodb_os_merge_buffers_written 0 Innodb_os_merge_buffers_read 0 Innodb_os_merge_buffers_merged 0 ALTER TABLE test_wo_keys ADD KEY `f06` (`f06`), ADD KEY `f05` (`f05`), ADD KEY `f04` (`f04`), ADD KEY `f23` (`f23`), ADD KEY `f10` (`f10`), ADD KEY `f11` (`f11`), ADD KEY `f09` (`f09`), ADD KEY `f22` (`f22`), ADD KEY `f21` (`f21`), ADD KEY `f07` (`f07`), ADD KEY `f08` (`f08`), ADD KEY `f18` (`f18`), ADD KEY `f19` (`f19`), ADD KEY `f20` (`f20`), ADD KEY `f29` (`f29`,`f31`,`f33`), ADD KEY `f35` (`f35`), ADD KEY `f25` (`f25`), ADD KEY `f26` (`f26`), ADD KEY `f27` (`f27`), ADD KEY `f28` (`f28`); show status like '%merge_buffers%'; Variable_name Value Innodb_os_merge_buffers_written 0 Innodb_os_merge_buffers_read 0 Innodb_os_merge_buffers_merged 0 DROP TABLE test_wo_keys;