[SR-Users] Changing acc_cdrs time and duration columns from varchar to int/float

Hello, I am planning to enable acc cdr in my kamailio 4.1 server. I am testing in my lab and it is working fine. However, when I check the table definition I see this: mysql> describe acc_cdrs; +------------+------------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +------------+------------------+------+-----+---------+----------------+ | id | int(10) unsigned | NO | PRI | NULL | auto_increment | | start_time | varchar(32) | NO | MUL | | | | end_time | varchar(32) | NO | | | | | duration | varchar(32) | NO | | | | +------------+------------------+------+-----+---------+----------------+ 4 rows in set (0.00 sec) The *_time and duration columns are defined as varchar. Because of this, i need to perform a cast when doing queries: select * from acc_cdrs where cast(start_time as unsigned) >= 1437120622; which would cause extra processing in the db server. So I experimented changing these columns to "int unsigned" and to "float unsigned" and it worked for both without problems (records properly added to acc_cdrs and no errors in kamailio.log): alter table acc_cdrs modify start_time int unsigned; alter table acc_cdrs modify end_time int unsigned; alter table acc_cdrs modify duration int unsigned; alter table acc_cdrs modify start_time float unsigned; alter table acc_cdrs modify end_time float unsigned; alter table acc_cdrs modify duration float unsigned; So I am thinking in doing this in my production server but I would like to know if there is any potential risk of doing this (as I am not sure why it was decided for these fields to be varchar instead of a numeric type). Regards, Takeshi