Hello to all,
In repeatable read isolation level, when we issue:

Select * from new where c1 between 12 and 17 for update;

this range will be locked by innodb by using next-key locks.

But, why is is preventing any other session to insert any value beyond that
range; any value above the range and any value below the range. I am unable
to understand this.

Best Regards,
Geetanjali Mehra
Senior Oracle and MySQL DBA Corporate Trainer and Database Security
Specialist