Report Application Server .NET SDK Developer Guide

Caching with RAS

RAS print job sharing

If many users view the same report, with the same logon information and parameters, RAS shares the print job between those users. RAS opens new print jobs and report documents only when necessary. This conserves server resources and leaves room for added scalability and performance.

For example, when a user opens a document that requires no database logon or parameter values, the server adds that document to the cache, and uses the name and location of the report as a unique key. If another user opens the same report, RAS runs the currently cached job, rather than open a second print job. After both users close the report, the print job remains in the cache until it expires, so that future requests for the report may reuse the cached copy without opening a new job.

However, most reports require a database logon or some parameter-specified values, which may be provided by users when they view the report, or by the ASP .NET code. RAS is unable to share print jobs for reports that require different values. For example, when a user opens a report, a print job is spawned and added to the cache, with a key that contains the logon and parameter values for that use. When a second user opens the report, a new print job is spawned with the logon and parameter values for the second user. Now two reports exist in the cache, one for each set of logon and parameter values. To conserve resources, when all the copies of the report are closed, only one remains in the cache.

Each time a user opens the report, the logon and parameters that are stored in the cache key for that report are updated with the values for that user. This ensures that each user is only able to see the data that is permitted by the logon and parameters provided.

Because reports that are modified cannot be shared with other users, modified reports are not cached. Therefore, if most users modify the reports they use, caching provides no performance benefit.

When a user modifies a cached report while no other user has it open, the item is removed from the cache, and that user is assigned exclusive rights to the print job. If another user has the cached report in use, a new print job is spawned for the modified report, but it is not cached.

Caching with RAS

RAS print job sharing

See Also