Oracle GoldenGate 12c supports up to 5,000 concurrent Extract and Replicat processes per instance. The actual amount of physical memory that is used by a process is controlled by the operating system up to its soft limit within the global system cache, not the GoldenGate program. However, the GoldenGate cache manager can be configured to reduce the process memory consumption if required.
The CACHEMGR parameter of the Extract or Replicat controls the amount of virtual memory and temporary disk space that is available to cache uncommitted transactions that are being processed by GoldenGate. As the cache manager adjusts itself internally, most production environments do not require changes to this parameter. However, if performance issues are evident, look at the statistics generated by the SEND EXTRACT or SEND REPLICAT GGSCI commands when used with the CACHEMGR CACHESTATS option. The statistics show the size of the memory pool, the paging frequency, the size of the transactions, and other information that creates a system profile, as shown in the following code:
GGSCI (db12server01) 1> SEND EXTRACT EOLTP01, CACHEMGR CACHESTATS Sending CACHEMGR request to EXTRACT EOLTP01 ... CACHE OBJECT MANAGER statistics CACHE MANAGER VM USAGE vm current = 256K vm anon queues = 256K vm anon in use = 0 vm file = 0 vm used max = 256K ==> CACHE BALANCED CACHE CONFIGURATION cache size = 64G cache force paging = 96G buffer min = 64K buffer max (soft) = 8M pageout eligible size = 8M =========================================================================== RUNTIME STATS FOR SUPERPOOL CACHE Transaction Stats trans active = 0 max concurrent = 177 non-zero total = 33 trans total = 3.87K CACHE File Caching filecache rqsts = 0 bytes to disk = 0 file retrieves = 0 objs filecached = 0 queue entries = 0 queue processed = 0 queue entry not needed = 0 queue not signaled = 0 fc requesting obj = 0 CACHE MANAGEMENT buffer links = 0 anon gets = 0 forced unmaps = 0 cnnbl try = 0 cached out = 0 ..