Getting duplicate primary key for auto increment column

Question

I have a MySQL Innodb table with 'id' as auto increment primary key column.

My Scripts are doing following operations:

1. insert ignore into tablename set x='a', y='b'
2. update ignore tablename set x='a', y='b' where id = 'smthing'
3. delete from tablename where id = 'smthing'

Now after running the script when I insert something manually (insert into tablename set x='ax', y='bx') I get the following error:

Duplicate Entry for Auto Increment Value. 

On check I see that Auto Increment is trying to put the highest possible value of int that MySql will support as new value even and it already exist in db.

The table has two index: id+x, id+y though idk if this is related to this issue.

Answer 1

I reached the max possible value of an int column. Problem resolved by altering table and setting big int than int.

The signed range of MIDINT is –8388608 to 8388607. The unsigned range is 0 to 16777215

Reference: http://help.scibit.com/mascon/masconMySQL_Field_Types.html