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DC.exe uses a large amount of memory

Question: I have experienced that the Data Collector (DC.exe) uses a large amount of memory.


Answer: The Data Collector will reserve larger amounts of working memory when receiving many data changes, especially changes that must be inserted into historical data (i.e. the data contains time-stamps backwards in time)


If your IGSS configuration permits updating of BCL files with historical data, the period which the Data Collector is permitted to update the BCL files with historical data may be too large, which will result in the Data Collector attempting to update BCL files further back in time. This will decrease the performance of the Data Collector and increase the memory used as the Data Collector will use as much memory as the size of the current BCL files.

By default, the Data Collector is set up to allow updating historic data into BCL files in a 27 hour period, but this default setting can be either increased or decreased.


If the period is increased, the Data Collector will retain BCL files in the system memory in anticipation of updating them with historical data values, increasing memory usage. The period cannot be decreased more than 24 hours, as the Data Collector will always retain the 4 BCL files for the past 24 hours in the system memory.


Open the System Configuration form and click the Configuration tab. In the Online field in the Historical values to BCL files group, you can set a new period. The values in the Online field are measured in seconds and thus 3600 seconds is one hour. The default value is 100,000 which results in a 27 hour period.


Additionally, you can also adjust the amount of log files to be cached in the memory at all times. Caching files increases performance as the application does not have to constantly read and write to the hard drive, but if your Data Collector is not receiving historical data to update the BCL files, caching old files is not necessary and will result in a larger memory usage.


By default, the application will cache 26 files, one for each hour of data but you can reduce this amount in order to reduce memory usage. This is also the maximum amount of log files that can be cached.


You can reduce the cached files by changing the MaxLoadedLogFiles registry key found in HKEY_CURRENT_USER \ Software \ 7-Technologies \ IGSS32 \ V9.00.00 \ DC_HKLM \ MaxLoadedLogFiles on the local machine.