Yesterday, i received an email from first level support about client complaint our system is sending over invalid message and caused their system threw exception.

I checked the spec provided and found that the field length is char(10) but we sent over char(15), okay this is fine i just need to do a super easy minor patching on the field, then everything will solve! But more interesting is when i look at their error log file:

<xx:Object>Exception occured: The conversion of the nvarchar value ‘888000000000008’ overflowed an int column. Maximum integer value exceeded. The statement has been terminated.</xx:Object>

HAHHA, apparently they are using INT data type for char field! Super easy to make their system throw exception in this case 🙂