QlikView relies on the cache for some of the content in the documents that visualize the data, as it is generated on the server-side. If the cache where to be turned off, the content would have to be retrieved every time the page is refreshed, which will cause the performance to degrade.
The risk highlighted, to have potential sensitive data stored locally, could be mitigated by policies for how workstations are to be handled by employees. Same thing goes for accessing sensitive data on public machines. It's a policy that should be enforced anyway, regardless of QlikView cache settings.
Environment:
IIS Active Cache stores static content, elements that does not change during the session for a user. It does not store any sensitive information as in charts or values. Neither does it store any logon credentials the user has provided. It might store the Display name the user sees in the AccessPoint. As stated previously, if you want to eliminate any risk of storing data, IIS allows you to disable the Cache for a more locked down environment, how big the performance impact will be depends on the volume of Documents and the complexity of them.
Resolution:
QlikView does not provide the option to disable caching, but there are several options for users who want to set no-cache/no-store:
Note: QlikView doesn't support below scenarios. Please do it at your own risk.
- Use IIS as WebServer instead of QlikView Web Server.
The possibility of using IIS to achieve the extra layer of security can be below, for example
http://support2.microsoft.com/kb/247404
http://www.iis.net/configreference/system.webserver/staticcontent/clientcache
- Modify htm and add
<meta http-equiv="Cache-control" content="no-cache">
<meta http-equiv="Cache-control" content="no-store">
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