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Background documentation OMS heap collisions Locate the document in its SAP Library structure

OMS heap collision rate <percentage>%, <number of> collisions during <number of> heap allocations/deallocations

Explanation

This message can occur for liveCache instances only.

Tasks that run in different threads attempt to request or release memory from the Structure linkOMS heap in parallel. This causes collisions.

User Response

Check whether the parameter Structure linkOMS_HEAP_COUNT, which determines the number of OMS heap segments, has an optimum value.

Generally, the risk of collisions rises with the number of processors used (database parameter MAXCPU). Check whether the liveCache can fulfill the requirements of the applications with fewer processors. If not, check whether the CPU on the server is overloaded, and whether the liveCache threads are blocked by other applications running on the server. In this case, the liveCache threads that contain user tasks; should have REAL TIME PRIORITY in the operating system. However, at the same time, the value of MAXCPU must be at least one lower than the number of real CPUs, to avoid operating system blocks.

 

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