Parameter
vmcj/nested_lock_loops
Short text
max loops to get a nested lock
Parameter Description
When requesting VM-wide locks (shared locks), the following points must be considered:
• If another lock is requested within an area protected by a shared lock, and the wrong sequence is used, a deadlock may result.
• If a VM-wide garbage collection is active, a VM that has just requested a shared lock must first contribute to the garbage collection before it can receive the shared lock. To enable this to happen, the lock request is not allowed to block. If a timeout occurs after the first attempt to receive the lock, the VM enters a loop during which control is relinquished for a short time, and the lock request is repeated.
The number of loops can be limited with the parameter vmcj/nested_lock_loops:
-1
Endless attempts are made to set the lock.
>= 0
Maximum number of attempts to set the lock. Each attempt lasts for about one second. If the lock still could not be set after n number of attempts, the lock request is rejected.
Application Area
VMC
Parameter Unit
Number greater than or equal to -1
Default Value
-1
Who is permitted to make changes?
Customer
Operating System Restrictions
None
Database System Restrictions
None
Are other parameters affected or dependent?
None
