About Pega 7 case locking

Pega 7 provides two case locking options and capabilities. You make your basic configurations in the Case Designer at the top-level case type. The settings cascade to all the subcase types.

• Default locking – When a case is opened in a Perform harness, it and its parent case are locked. Only one user can view and update the case at a time. You can override the default behavior at the each subcase type level.
• Optimistic locking​ – Multiple users can open a case in a Perform harness at the same time to review or update it. The first user to submit an update "wins;" users who had updated the form but had not submitted changes must refresh the form, re-enter their updates, then submit them.

This article describes how these locking strategies work and how you configure them in the Case Designer.

Approach
To begin, open a top-level case type in the Cases Explorer and open the Details tab. On the Locking option, click the Edit link.

Default Locking
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Sets to standard locking behavior; the system locks a case when it is opened by a user for a period of up to 30 minutes. No other user can open or work on it. You can change the standard time period in the Custom timeout field.
This conservative approach helps ensure that data can be updated in both parent and subcases with transaction integrity. For example, the parent case may contain properties that count or total values in the subcase. Locking both at once helps keep these counts or totals in sync.
Overriding default lockingIf default locking hampers user throughput in your application, you can override the setting at the subcase level. This lets users concurrently make updates to both parent cases and their subcases without conflict.

To override default locking:

1. Open the subcase type in the Case Designer's Details tab.
2. Open the Locking pop-up dialog.
3. Select the Do not lock the parent case when the child case is being performed checkbox and click the Save button.

Note  This setting is not available for optimistic locking since there is no lock on either the parent or the subcase.

Optimistic lockingThe top-level case and all of its subcases can be opened in a Perform user form by multiple users for reviews or updates. This setting applies to all subcases and cannot be overriden at the individual casetype level.

When the first user submits or saves an update, other users who have also opened the case and attempt to submit their updates receive a message indicating that the original form and its data have already been updated; therefore, they cannot submit their updates. In these situations, users can:

• Close their case without submitting the changes.
• Refresh the form to see the other user's updates before submitting their own updates. Users cannot commit changes without using the review option.

 Note :  The system compares .pxLastUpdateTime of the case on clipboard to the DB’s object to determine whether another user has committed an action since the current user has opened the case.

Considerations
​In most configurations, use default locking in order to preserve transaction integrity among cases. Optimistic locking may be called for where multiple users need only open and review cases without having to perform updates.

• If it is likely that a multiple users will attempt updates to cases in one or more case types, frequent update conflicts will likely not be desirable.
• Agents and services such as SLAs and bulk actions can update a case that is being worked by an operator. When the user attempts to save work, the update will fail.
• It is possible to create a condition that accepts updates from two operators at same time, although one user's work will not be committed. Audit trail entries for both updates may be present and might actually interleave.
• If a subcase update attempts to update its parent, the system briefly locks the parent to effect the update. If the parent is locked, the updates are queued until a lock can be obtained.