| Measurement |
Description |
Measurement Unit |
Interpretation |
| ContainerExclusiveLocks |
Indicates the rate of Exclusive lock requests on Containers during the last measurement period. |
Locks/second |
A high value indicates that there is high locking activity in the database server.
|
| ContainerSharedLocks |
Indicates the rate of Shared locks requests on Containers during the last measurement period. |
Locks/second |
A high value indicates that there is high locking activity in the database server.
|
| ContainerCollusionLocks |
Indicates the rate of lock collisions on Containers during the last measurement period. |
Collisions/second |
A lock collision occurs when tasks running in different threads attempt to access a global storage area in parallel. The synchronization required for this often leads to an increased collision rate.
Note:
One exception to this in SAP liveCache databases is high collision rates in the OMSVDIR and CNSTVIEW regions (). This is normal for certain actions, such as a simultaneous CIF queue transfer.
You need to act if the collision rate rises above 10%. Generally, the risk of collision rises with the number of processors used (MaxCPUs general database parameter). In multiprocessor systems, you should therefore check whether the database system can fulfill the needs of the applications with fewer CPUs.
If high collision rates occur in multiprocessor central systems (database system and application running on the same computer), check whether the computer’s CPU is overloaded, and whether the database threads are blocked by other applications. In this case, the database threads that contain user tasks should have received REAL TIME PRIORITY in the operating system. To avoid operating system blocks however, the value of MaxCPUs must be at least one lower than the number of actual CPUs.
|
| ContainerTimeOutLocks |
Indicates the rate at which lock requests timed-out instead of being granted on Containers during the last measurement period. |
Timeouts/second |
A high value for this measure indicates that many statements were cancelled, as they could not acquire a lock on a resource for a long time. This may be due to another extent lock holding the resource (An extent lock is the one which locks multiple resources).
|
| SchemaExclusiveLocks |
Indicates the rate of Excluisve lock requests on Schemas during the last measurement period. |
Locks/second |
A high value indicates that there is high locking activity in the database server.
|
| SchemaSharedLocks |
Indicates the rate of Shared locks requests on Schemas during the last measurement period. |
Locks/second |
A high value indicates that there is high locking activity in the database server.
|
| SchemaCollusionLocks |
Indicates the rate of lock collisions on Schemas during the last measurement period. |
Collisions/second |
|
| SchemaTimeOutLocks |
Indicates the rate at which lock requests timed-out instead of being granted on Schemas during the last measurement period. |
Timeouts/second |
A high value for this measure indicates that many statements were cancelled, as they could not acquire a lock on a resource for a long time. This may be due to another extent lock holding the resource (An extent lock is the one which locks multiple resources).
|
| ObjectExclusiveLocks |
Indicates the rate of Exclusive lock requests on Objects during the last measurement period. |
Locks/second |
A high value indicates that there is high locking activity in the database server.
|
| ObjectSharedLocks |
Indicates the rate of Shared locks requests on Objects during the last measurement period. |
Locks/second |
A high value indicates that there is high locking activity in the database server.
|
| ObjectCollusionLocks |
Indicates the rate of lock collisions on Schemas during the last measurement period. |
Collisions/second |
|
| ObjectTimeOutLocks |
Indicates the rate at which lock requests timed-out instead of being granted on Objects during the last measurement period. |
Timeouts/second |
A high value for this measure indicates that many statements were cancelled, as they could not acquire a lock on a resource for a long time. This may be due to another extent lock holding the resource (An extent lock is the one which locks multiple resources).
|