range columns including datetime column

[Rob Voyer]

I have a large reporting table that is difficult to manage (disk space problems) so I am trying to partition it using range columns including a datetime column. When I insert or select, it doesn't respect the partitions and particularly the datetime values. Here is my create table statement:

CREATE
TABLE sessions_grouped_partitioned
(
period SMALLINT NOT NULL,
START DATETIME NOT NULL,
group_by_type SMALLINT NOT NULL,
group_by_value_1 VARCHAR(30),
group_by_value_2 VARCHAR(30) NOT NULL,
group_by_value_3 VARCHAR(30) NOT NULL,
id bigint unsigned NOT NULL AUTO_INCREMENT,
PRIMARY KEY (id, period, START),
UNIQUE INDEX groupByOneTwoThree (period, START, group_by_type, group_by_value_1, group_by_value_2, group_by_value_3),
INDEX groupByTwoOneThree (period, START, group_by_value_2, group_by_value_1, group_by_value_3)
)
ENGINE=InnoDB DEFAULT CHARSET=utf8

PARTITION BY RANGE COLUMNS(period,start) (
PARTITION p123 VALUES LESS THAN (4, '2015-01-01 00:00:00'),
PARTITION p45_1205 VALUES LESS THAN (6,'2012-06-01 00:00:00'),
PARTITION p45_1206 VALUES LESS THAN (6,'2012-07-01 00:00:00'),
PARTITION p45_1207 VALUES LESS THAN (6,'2012-08-01 00:00:00'),
PARTITION p45_1208 VALUES LESS THAN (6,'2012-09-01 00:00:00'),
PARTITION p45_1209 VALUES LESS THAN (6,'2012-10-01 00:00:00'),
PARTITION p45_1210 VALUES LESS THAN (6,'2012-11-01 00:00:00'),
PARTITION p45_1211 VALUES LESS THAN (6,'2012-12-01 00:00:00'),
PARTITION p45_1212 VALUES LESS THAN (6,'2013-01-01 00:00:00'),
PARTITION p45_1301 VALUES LESS THAN (6,'2015-01-01 00:00:00')
);

I can get rows to go into only the first two partitions (p123 and p45_1205). I read someone's post elsewhere that they had a similar problem. They mentioned changing their my.cnf file but didn't specify exactly what they changed. Hoping there is an obvious solution! I just upgraded to 5.5.27 so I could do this easily without having to change my current table structure.

I have also tried using MAXVALUE above instead of far out values like 2015 but that causes an error in creating the table. Thanks