## OMS Heap Collisions

### 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 OMS heap in parallel. This causes an increase in the number of collisions.

### User Response

Check whether the liveCache database parameter OMS_HEAP_COUNT, which determines the number of OMS heap segments, has an optimum value. See Concepts of the Database System, liveCache database parameters.

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