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Use

Caching stores in memory for a preconfigured amount of time content that has been retrieved by an iView request. Successive identical requests first access the cache, rather than resubmitting the query to the data source, and if the cache has not expired, the iView displays the information stored there. Caching improves response time and overall system performance by reducing the load on the information source.

While you would usually use the portal cache to improve the response time of content that does not change frequently, applying caching to content that is updated often is also worthwhile, because time is still saved when generating the content.

The browser has a similar mechanism to that of the portal cache, whereby it can store content on the client side and display it as long as it is valid. This further improves response time by reducing the load on the portal, because the browser uses its stored content instead of requesting it from the portal.

Integration

The caching mechanism is part of the portal runtime and operates according to specific application and iView settings. Activating the various levels of caching entails configuring iView properties that:

  • Allow caching in the client browser

  • Set the cache level

  • Set the validity period of the cache

  • Automatically refresh iViews from cache (BW 2.x / 3.x iViews only)

Caution

The Enable Client-Side Caching property is an application cache property that administers the client browser cache. You can use this property to override your iView cache settings. For information about setting application caching properties, see Configuring Application Caching .

Allow Client-Side Caching

This property is used to define whether an iView's content can be cached in the client browser, as well as in the portal cache. If caching an iView on the portal improves performance, then allowing client-side caching further enhances it.

The only drawback to client-side caching concerns iViews that display sensitive or private content, which you would not want to store locally on the browser machine.

The property values are:

Selected

Enable browser cache settings to be defined per iView.

This is the default value.

Deselected

Disable the browser cache for all iViews, regardless of individual iView settings.

Cache Level

You determine the cache level according to the content of the iView, the speed of retrieval, and the configured time of loading. The four cache levels are:

None

iView content is never cached. Each time the iView is launched, it accesses the content source. This level is appropriate for iViews retrieving information that is constantly changing and being updated, such as a news bulletin iView, or a ticker to a stock exchange.

This is the default value.

Session

iView content is cached for the current session. Each new logon empties the cache and the iView must access the source. An iView retrieving secured content would likely use this level.

User

iView content is cached per user. New users who launch the iView receive content from the data source. An iView representing a user's daily tasks is appropriate for this cache level.

Shared

iView content retrieved by first user is cached for all users. This level is suitable for iViews displaying information relevant to all users, such as company announcements.

Roles

iView content is cached for all users with the same combination of roles (one instance per role combination). This level is used specifically for caching the Top-Level Navigation iView in the Classic Framework Page . For more information, see Configuring Properties Specific to the Classic Framework Page .

Note

Another possibility, which would be compatible with all the cache levels except None , is to set the iView Cache Validity period (see below) to -1 , creating an always-cached situation. An iView whose content never changes, such as a Welcome iView, does not require updating.

To set an iView's cache level, in the Property Editor of the iView in focus, browse to the Cache Level property and choose the level that you want to assign.

Cache Validity

This setting defines the expiration time of iView content stored in cache. Once the cache has expired, the iView must access the data source for its content.

Note
  • Refreshing an iView from the Options menu forces it to retrieve updated content from the source, even if the cache is still valid.

  • Refreshing a page from the Options menu forces iViews to update their content from the source, even if their caches are still valid.

  • iViews whose cache level is set to Shared are not affected, since all users receive identical content that cannot be individually updated.

Cache validity is respected, regardless of any particular cache level except for None . For example, if the cache level is Session , and the cache validity is set to two hours, the iView content is retrieved from source the first time a user logs on. Then content comes from the cache for the next two hours only, even if the session lasts four hours.

Note

Synchronize cache validity and cache level as logically as possible.

To set an iView's cache validity, in the Property Editor of the iView in focus, browse to the Cache Validity Period property, and enter the time frame that you need. Cache validity is measured in milliseconds.

Business Intelligence iViews

Formerly, the portal had to issue separate requests to the cache and to the BI back end application to display BI content. Now the portal serves as a proxy between BI and the browser. The portal can request and retrieve BI content, including SAP items such as icons, and store both the iViews and the images in the cache. The portal also authenticates all BI content, thereby resolving security and performance issues.

The Time Interval to Refresh iView property, available to BW 2.x / 3.x iViews only , tells the portal to automatically query the server for new content every specified number of seconds and refresh a cached iView.

The values are:

Selected

Portal queries the server automatically; iView displays refreshed content.

Deselected

Portal does not query the server automatically; iView displays what is in cache.

Caution

Caching is not supported for SAP NetWeaver BI 7.0 iViews.

Page Caching

The portal supports a page caching mechanism that caches an entire page with its embedded iViews. No configuration is necessary. The mechanism automatically determines:

  • Whether the page can be cached

  • The cache level, according to the type of iViews comprising the page

The validity period remains viable until any of the iViews are changed.