SELECT MAX(EventDetails.EventProperties.value.System.TotalMemory)-MIN(EventDetails.EventProperties.value.System.TotalMemory)
FROM 'file://C:\Users\Steven.Dawkins\Documents\visual studio 2013\Projects\HermesToJsoql\HermesToJsoql\bin\Debug\Events\Hermes_20150403.jsonl'
WHERE SubCategory = 'Heartbeat'