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.
Host	The host name of the server for which the test is to be configured.
Port	The port number to which the server is listening.
DatabaseName	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.
Username	Since users with the SYSDBA privilege alone are allowed access to system tables, specify the name of such a user against Username.
Password	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.	MB	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.	MB
Memory allocation rate	Indicates the number of memory allocations per second.	Allocations/Sec	A higher rate indicates higher and faster memory utilization.
Memory release rate	Indicates the number of memory releases per second.	Releases/Sec
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.	Attempts/Sec	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.	Collisions/Sec
Spinloop rate	Indicates the rate at which attempts were made to acquire a spinlock without prior release of the CPU.	Attempts/Sec
Yieldloop rate	Indicates the rate at which attempts were made to acquire a spinlock after prior release of the CPU.	Attempts/Sec
Errors rate	Indicates the rate at which errors were detected and automatically corrected.	Errors/Sec