Read lock table information programmatically; remove locks; query and adjust lock table parameters.
An important feature of any multi-process system is concurrency control, the ability to prevent different processes from changing a specific element of data at the same time, resulting in corruption. Thus ObjectScript
and InterSystems SQL
each provide commands for working with locks
, which you use for concurrency control.
class provides a way to control concurrent access to objects, namely, the concurrency
argument to %OpenId()
and other methods of this class. These methods ultimately use the ObjectScript LOCK command. All persistent objects inherit these methods.
Internally, the in-memory lock table
contains the current locks, along with information about the processes that hold those locks. You can use the Management Portal to view the lock table and (if necessary) remove locks; see Monitoring Locks
in the Monitoring Guide
In addition, InterSystems provides the following tools:
Enables you to read lock table information. This class provides details and examples.
Enables you to remove locks. Also enables you to query and adjust lock table parameters. This class provides methods like the following: