ISSUE: Queries with mediumint as column when operated with
long long type of data results in buffer overflow in
store_long function.

The merging rule specified for (MYSQL_TYPE_LONGLONG
MYSQL_TYPE_INT24) is MYSQL_TYPE_LONG. Due to this store_long
function was getting called which resulted in buffer overflow.

SOLUTION:
The correct merging rule for (MYSQL_TYPE_LONGLONG,
MYSQL_TYPE_INT24) should be MYSQL_TYPE_LONGLONG.
So, instead of function store_long, function store_longlong
is called which correctly handles the type MYSQL_TYPE_LONGLONG.

External Bug #23645238 is a duplicate of this issue.