cluster - what is gen_clust_index used for in mysql?

It seems I have a deadlock in mysql (running innodb) that's due in part to a lock on gen_clust_index, however, this isn't a table that I've created.

So... what's the short and sweet description of gen_clust_index and it's use and purpose in mysql.

Answer

Whenever you create a table with the InnoDB storage engine, an internal clustered index is generated under its hood. This is especially true if an InnoDB table has no Primary Key and no Unique Indexes.

Click here for MySQL Description of That Hidden Clustered Index

I hope this was short and sweet !!!