SAP Parameter vmcj/nested_lock_loops - max loops to get a nested lock


Short text
max loops to get a nested lock
When requesting VM-wide locks (shared locks), the following points mustbe 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 itcan receive the shared lock. To enable this to happen, the lock requestis not allowed to block. If a timeout occurs after the first attempt toreceive the lock, the VM enters a loop during which control isrelinquished for a short time, and the lock request is repeated.
      The number of loops can be limited with the parametervmcj/nested_lock_loops:
      Endless attempts are made to set the lock.
      >= 0
      Maximum number of attempts to set the lock. Each attempt lasts for aboutone second. If the lock still could not be set after n number ofattempts, the lock request is rejected.

      Work area

      Parameter unit
      Number greater than or equal to -1

      Default value

      Who is allowed

      Limitation for os

      Limitation for db

      Other parameter