In the JADE language, you can use the
Share | Reserve | Update | Exclusive | |
---|---|---|---|---|
Share | Yes | Yes | Yes | No |
Reserve | Yes | No | No | No |
Update | Yes | No | No | No |
Exclusive | No | No | No | No |
More than one shared lock can coexist for the object at any time but only one exclusive lock is allowed. Additionally, a reserve lock can coexist with any number of shared locks but is incompatible with another reserve lock or with an exclusive lock. If the object to be locked is already locked in an incompatible manner by another user or sub-user, an exception is raised.
The lock types and their global constant definitions (if applicable) are listed in the following table.
|
Integer | Description |
---|---|---|
Get_Lock | 0 | Waiting to acquire a lock and forcing all other lock requests to be queued |
Share_Lock | 1 | Shared lock. |
Reserve_Lock | 2 | Reserve lock. |
Exclusive_Lock | 3 | Exclusive lock |
Update_Lock | 4 | Update lock |
The lock duration global constant definitions are listed in the following table.
|
Integer |
---|---|
Transaction_Duration | 0 |
Session_Duration | 1 |
Persistent_Duration (reserved for future use) | 2 |
The lock timeout global constant definitions are listed in the following table.
|
Integer Value |
---|---|
LockTimeout_Immediate | -1 |
LockTimeout_Infinite | Max_Integer (#7FFFFFFF) |
LockTimeout_Process_Defined | -2 (use the process‑defined default lock request timeout) |
LockTimeout_Server_Defined | 0 (use the server-defined default) |
You can specify a default lock timeout for a background process in the BackgroundProcessServerTimeout parameter in the [
You should not change the BackgroundProcessServerTimeout parameter value unless the background process is having locking problems. Before you increase this value, examine the application to determine which objects are being locked and whether locks are being held for too long. For example, new nodes cannot sign on if the system.nodes dictionary is locked by the application. It is better to change the application to minimize the locking of system collections.