Purging OBI Server and Presentation Server Cache:

Purging BI Server Cache:

• BI Server cache is stored in the directory: d:\Oracle\OracleBIData\cache • Create the script called PurgeBICache.sql with following command:

Call SAPurgeAllCache ();

• Run the following command to invoke the script and clear the cache: nqcmd -d AnalyticsWeb -u Administrator -p Administrator -s PurgeBICache.sql -o purge_clear.log

• This will clear all the BI server cache entries for all the users.

Purging BI Presentation Server Cache:

        Presentation cache stores the finished report output in the presentation server. This is different from BI server cache. BI server could be leveraged by multiple users and reports depending on whether they are accessing similar or subset of the cached data, though from a different reports.

 Presentation cache is report specific and user specific cache entries residing in the D:\OracleBIData\tmp\ folder.

The expiry of this entry can be governed by following instance-config.xml file in <>\web\config directory:

CacheMinExpireMinutes Default 10

CacheMaxExpireMinutes Default 15

 

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Cache Management Techniques

Cache:

Oracle BI Server can be configured to maintain a disk-based cache of query results sets:
• Saves the results of queries in cache files
• Enables Oracle BI Server to satisfy subsequent query requests without having to access back-end databases

Overhead because of Caching:
• Disk space
– Query cache requires dedicated disk space.
• Administrative tasks:
– Set the cache persistence time appropriately.
– Purge the cache when necessary.
• Keeping the cache up-to-date:
– Evaluate what level of noncurrent information is acceptable.
– Remove stale data.

Cache Management Techniques
• Configuring the cache parameters
• Setting caching and cache persistence for tables
• Using the Cache Manager
• Inspecting SQL for cache entries
• Modifying the Cache Manager column display
• Inspecting the cache reports
• Purging the cache entries manually using the Cache
Manager
• Purging the cache entries automatically
• Using event polling tables
• Seeding the cache

Cache Hit Conditions
A cache hit occurs only when certain conditions are met, such
as the following:
• Query WHERE clause constraints need to be equivalent to the cached results or to a subset of the results.
• All the columns in the SELECT list of a new query must exist in the cached query or they must be able to be calculated from the columns in the query.
• Join conditions must be equivalent.
• Queries that request an aggregated level of information can use cached results at a lower level of aggregation.

 

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