The Qlikview Cache

[nikhilgarg]

Hey,

I was going thru the following link:

The QlikView Cache

There i couldn't understand the below point. Can someone help me understanding this?

• Memory is not returned, when the document is unloaded. Cache entries will usually not be purged until the RAM usage is close to or has reached the lower working set limit. QlikView will then purge some entries and re-use the memory for other cache entries. This behavior sometimes makes people believe there is a memory leak in the product. But have no fear – it should be this way. So, you do not need to restart the service to clear the cache.

[#2]

During normal operation, the RAM footprint of the QVS will generally continue to grow up to the max working set limit.   For simplicity's sake, let's say you have 100GB of RAM on the server, and high working set limit of 90%.  When you start the QVS, it might consume a few GB, and over time, the RAM consumed by the QVS would typically continue to grow as the QVS is used and results are added to the cache up to the max working set of 90GB (i.e. 90% of 100GB).  At this point, the QVS would typically begin to remove stale cache entries (it has an algorithm to do this based on a number of inputs) to make way for newer results in the cache, and you would see the RAM usage of the QVS process hover around the 90GB mark.  This is a very simplified description (there are a number of other complexities that can creep in), but is generally what we see in our environments. 

Regards,

Graeme