Metadata cache spinlocks (configured by the open index hash spinlock ratio, open index spinlock ratio, and open object spinlock ratio parameters) use the round-robin assignment method.
This figure shows one example of the round-robin assignment method and shows the relationship between spinlocks and index metadata descriptors.
Suppose there are 400 index metadata descriptors, or 400 rows, in the index descriptors internal table. You have set the ratio to 100. This means that there are 4 spinlocks: Spinlock 1 protects row 1; Spinlock 2 protects row 2, Spinlock 3 protects row 3, and Spinlock 4 protects row 4. After that, Spinlock 1 protects the next available index descriptor, Index Descriptor 5, until every index descriptor is protected by a spinlock. This round-robin method of descriptor assignment reduces the chances of spinlock contention.