Db Oms Stats Test

Object management system (OMS) is a type of data management. Only SAP liveCache database instances use OMS. SAP liveCache is an enhancement of the MaxDB relational database system. In SAP liveCache, the actual data structures and data streams (such as networks and relationships) can be mapped more easily and effectively. A large part of the data in a SAP liveCache database instance is managed in objects. This object data is called OMS data. OMS data is managed in containers that are assigned to precisely one persistent C++ class of the object type, and is edited in the OMS intermediate layer. The OMS data pages are in the data cache. The Db Oms Stats test measures how well the SAP liveCache manages objects using OMS.

Target of the test : A MaxDB server

Agent deploying the test : An internal agent

Outputs of the test : One set of results for every liveCache object on the MaxDB server being monitored.

Configurable parameters for the test
Parameter Description

Test Period

How often should the test be executed.


The host name of the server for which the test is to be configured.


The port number to which the server is listening.


The test connects to a database on MaxDB and extracts performance statistics from the system tables in the database. Therefore, provide the name of a database in the DatabaseName text box.


Since users with the SYSDBA privilege alone are allowed access to system tables, specify the name of such a user against Username.


Provide the Password that corresponds to the specified Username.

Confirm Password

Confirm the password by retyping it here.

Measurements made by the test
Measurement Description Measurement Unit Interpretation

Heap used

Indicates the liveCache memory that is been used currently.


The memory requirements in the OMS heap are very high for the running DB procedures. If the memory utilization in the OMS heap reaches 100% of its limit, there is the risk of errors in the DB procedures (Out of Memory Exceptions), or that OMS version data is swapped from the OMS heap to the global data cache (OMS version is unloaded). It is recommended that you configure the general database parameter CACHE_SIZE and the liveCache parameter OMS_HEAP_LIMIT in such a way that it prevents swapping at the operating system level and errors in DB procedures.  

Reserved size

Indicates the memory managed by the allocator.



Memory allocation rate

Indicates the number of memory allocations per second.


A higher rate indicates higher and faster memory utilization.

Memory release rate

Indicates the number of memory releases per second.



Spinlock rate

When a requested lock is not available, then the process will spin and try again to acquire the lock. This is known as a Spinlock. This measure indicates the number of attempts that were made per second to acquire a spinlock.


A consistent increase in this rate indicates that some locks have been held for too long a time.

Collision rate

Indicates the rate at which attempts to get a spinlock failed.



Spinloop rate

Indicates the rate at which attempts were made to acquire a spinlock without prior release of the CPU.



Yieldloop rate

Indicates the rate at which attempts were made to acquire a spinlock after prior release of the CPU.



Errors rate

Indicates the rate at which errors were detected and automatically corrected.