The Encyclopedia volume stores persistent documents and designs until removed by the user. Temporary documents are not stored in the Encyclopedia volume. The administrator can configure caching to improve viewing performance for a particular environment.

The administrator can configure caching to improve performance of viewing small, temporary, and persistent BIRT documents. iHub caches BIRT documents of a size equal to or smaller than the value appearing in Maximum memory size of each BIRT report archive. When a user requests a document of a size larger than this value, iHub temporarily stores the document on the hard drive.

The total memory size used to cache BIRT document and datamart files value determines how much memory iHub can use to cache documents. Increasing this value caches more BIRT documents in memory, consuming more memory. Decreasing this value temporarily stores more BIRT documents on the hard drive.

To optimize performance, the administrator tries to prevent storing most documents on the hard drive by making configuration decisions based on the size of the average document and the size of the cache.

The administrator can also set the time-out period for temporary and persistent document caches. When the time elapses, iHub clears the cache.

The following snippets from the default acmetadescription.xml include the acmetadescription.xml parameter names, the corresponding display names of the Configuration Console properties, when property changes take effect, and default values:

The Java View service handles on-demand document generation requests and multiple concurrent requests, one at a time. Configuring the size of the buffer that stores the result sets for a data set in a BIRT document can improve the response to on-demand requests to generate BIRT documents. An administrator typically changes the size of this buffer from the default to another value under the following conditions:

Increasing the size of the result set buffer for a BIRT data object query increases the memory used to store the final result set, and decreases the disk space used. If the result set is larger than this value, iHub writes the data to disk.

The following snippet from the default acmetadescription.xml includes the acmetadescription.xml parameter name, the corresponding display name of the Configuration Console property, when a property change takes effect, the default value, and range:

The administrator can configure the cache of images in persistent BIRT documents by setting cache time‑out for images and charts from BIRT designs, documents and datamarts. Increasing this value increases the size of the memory buffers for caching images. Graphic-intensive documents load faster, but iHub uses more memory.

The following snippet from the default acmetadescription.xml includes the acmetadescription.xml parameter name, the corresponding display name of the Configuration Console property, when a property change takes effect, and the default value:

By default, iHub caches a BIRT design, including access privileges. Caching benefits users who access the design concurrently. Users who request access to the same design share the cached design if they have the required privileges. Performance can improve because iHub does not have to repeatedly load the design. Generally, the fewer number of designs iHub needs to load, the better the response time.

By configuring cache time-out for BIRT designs, the administrator can control how long the design remains in cache. A cached design persists in memory until time‑out occurs. Use this time‑out setting to control memory usage.

By configuring the maximum number of BIRT designs, the administrator controls the number of designs in the cache. When the cache reaches this limit, design caching stops. Use this setting to improve load performance.

The following snippets from the default acmetadescription.xml include the acmetadescription.xml parameter names, the corresponding display names of the Configuration Console properties, when property changes take effect, and default values:

By default, iHub caches a BIRT document, including access privileges. Caching benefits users who access the document concurrently. Users who request access to the same document share the cached document if they have the required privileges. Performance can improve because iHub does not have to repeatedly load the document. Generally, the fewer number of documents iHub needs to load, the better the response time. iHub caches BIRT documents in the BIRT document in-memory archive cache. To access the cache, iHub creates a handle. If you enable the BIRT document cache, iHub caches this handle in the BIRT document cache. If you do not enable the BIRT document cache, iHub creates a new handle every time a user chooses to view a document. Enabling the BIRT document cache results in a faster response time but uses more memory, because iHub maintains the BIRT document cache in memory.

The following snippets from the default acmetadescription.xml include the acmetadescription.xml parameter names, the corresponding display names of the Configuration Console properties, when a property change takes effect, and the default values: