OBIEE11g: Managing the Oracle BI Presentation Services Cache Settings

When users run analyses, Presentation Services can cache the results of those analyses. Presentation Services determines if subsequent analyses can use cached results. If the cache can be shared, then subsequent analyses are not stored.
The files for the Presentation Services cache have names such as nQS_xxxx_x_xxxxxx.TMP. The files are created by the ODBC driver but generally do correspond to ODBC requests that the Presentation Services cache keeps open. The files are stored in the following directory:
ORACLE_INSTANCE\tmp\OracleBIPresentationServices\coreapplication_obipsn\obis_temp
The files for the cache are removed whenever Presentation Services shuts down cleanly. If Presentation Services shuts down unexpectedly, then various cache files might be left on disk. You can delete the files when Presentation Services is not running.
The Presentation Services cache is different from the cache that is accessed by the Oracle BI Server. You can change the defaults for the Presentation Services cache by modifying the instanceconfig.xml file to include the cache entries.
The following procedure provides information about configuration changes with which you can manage the Presentation Services cache.


To manually edit the settings for managing the cache:

1. Open the instanceconfig.xml file for editing
   
2. Locate the section in which you must add the elements
   
   Note:

   Avoid specifying values of less than 3 minutes for the elements that affect minutes. At such a low amount of time, refreshes can occur frequently, which can negatively affect performance and cause flickering on the screen.
   
3. Include the elements and their ancestor elements as appropriate, as shown in the following example:
   

   <ServerInstance>
     <Cache>
       <Query>
         <MaxEntries>100</MaxEntries>
         <MaxExpireMinutes>60</MaxExpireMinutes>
         <MinExpireMinutes>10</MinExpireMinutes>
         <MinUserExpireMinutes>10</MinUserExpireMinutes>
       </Query>
     </Cache>
   <ServerInstance>
   

4. Save your changes and close the file.
   
5. Restart Oracle Business Intelligence.
   

Table 7-7 Elements for Configuring the Cache for Presentation Services

Element	Description	Default Value
MaxEntries	Specifies the maximum number of open record sets that Presentation Services keeps open at any one time. The minimum value is 3. For systems under significant loads, you can increase this value to 700 or 1000.	500
MaxExpireMinutes	Specifies the maximum amount of time, in minutes, that an entry in the cache can exist before it is removed. Depending on the number of analyses being run, an entry might be removed before the time limit expires.	60 (one hour)
MinExpireMinutes	Specifies the minimum amount of time, in minutes, that an entry in the cache can exist before it is removed. The setting for CacheMinUserExpireMinutes can force an entry for a particular user to exist for a longer time than that specified by the CacheMaxExpireMinutes element.	10
MinUserExpireMinutes	Specifies the minimum amount of time, in minutes, that an entry in the cache can exist after it has been viewed by a user. For example, if CacheMaxExpireMinutes is set to 60 minutes and a user views the entry during the 59th minute, the entry exists for that user for an additional 10 minutes. The user can continue paging through the data without requiring a new analysis to be run.	10