Pega Locking Interview Questions

1. How you can force release a lock ?

Ans.  Lock information is held in the memory of each node, rather than in the database, for improved performance. However, even in a multinode system, a requestor can force the release of locks held by any session with the same Operator ID and same user name (pyUserName) through the PublicAPI method: LockManager.unlock(StringMap, boolean)

 

2. What debugger you will use to troubleshoot Lock related issues ?

Ans. com.pega.pegarules.engine.database.LockManagerImpl

 

3. What is soft lock?
Ans. An expired or “soft” lock remains held by a requestor session until the session releases it or until the requester session ends, but a soft lock can be stolen — broken and acquired — by another requester who opens the instance. In that case, any updates by the first user that are not committed are lost.

 

4. How long a lock can be held?

Ans. Generally, a thread that acquires a lock retains it until the instance is saved again with a Commit method (which may complete an Obj-Save or Obj-Delete method). However the system automatically expires locks held longer than a specified timeout period. You can change the default timeout interval of 30 minutes to a longer or shorter period. This value is stored in the Data-Admin-System data instance.

 

5. What is lock string?

Ans. A lock string uniquely identifies a lock. For instances that belong to classes not associated with a class group, the text string consists of the class name concatenated with the key parts of the object (determined on the Keys area of the Basics tab of the Class form, or the Locking tab of the Class form).

 

6. What is the significance of lockInfo Page ?

Ans. If a method failed to acquire a lock because the object is already locked, information on this page identifies the current requestor session that holds the lock. By convention, this page is named LockInfo in standard rules.

 

7. What are the methods that require acquiring a lock?
Ans. Obj-Open, Obj-Open-by-Handle, and Obj-Refresh-and-Lock

 

8. A system admin wants to know whether there is any report which helps him to get the lock details or not. Can you assist him on this ?

Ans. To view all locks held by any requester, select Designer Studio > Process and Rules > Tools > Work Admin > All Locks, and drill down to identify the details of the locked object. Hold the mouse pointer over a row of the drill-down detail to identify the Operator ID of the requester holding the lock.

 

9. When can a requester acquire a lock?

Ans. A requestor can lock an open instance if all of the following are true: The instance belongs to a concrete class that has Allow Locking? selected in the class rule.
AND the instance has ever been saved and committed to the PegaRULES database. The requestor has an access role that conveys the privilege needed.

 

10. What do you mean by locking?
Ans. Locks are exclusive to one Thread, and operate system-wide in a multinode system


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