Working with Report Manager - Learning SQL Server Reporting Services 2012 - page 229

You can also schedule the subscription by using the other two options
in Step.6 .
This will, however, make an event (timer) driven subscription.
The previous subscription was edited to a timed one and ran once.
The subscription status changed as shown in the following screenshot.
However, the GMAIL has not yet (last checked at 09:17 A.M.) delivered
the report in PDF.
Data-driven Subscriptions are only supported in Enterprise
and Business Intelligence Editions of SQL Server 2012.
In the next section Report caching will be described.
Report caching
You can cache a copy of a processed report on the Report Server and serve a cached
copy from the server. Since the cached information is retrieved from the temporary
location where it was stored the first time it was requested, the turn-around is very
fast as no data is queried again. The idea of report caching is very much analogous
to Web page caching.
This can be turned on for individual reports by the user. There is a cache lifetime
that can be specified as you do not need the same report forever. In addition, it can
affect resources. The report cache can also bring in problems of security breaches and
to mitigate this, the report should only be available to the user or group that created
the cache in the first place. Hence, the user who creates the cache must have the
report data source configured to store his credentials.
The Report cache is a step before the final rendering and therefore it is in an
intermediate format internal to reporting services and can be rendered in a chosen
format at the time of printing or using a cached copy. The cached report has a finite
lifetime after which it is removed. It may also be removed if the underlying report
is updated to reflect new information.