Siebel Analytics Server Administration Guide > Query Caching >

Monitoring and Managing the Cache

To manage the changes in the underlying databases and to monitor cache entries, you need to develop a cache management strategy. You need a process to invalidate cache entries when the data in the underlying tables that compose the cache entry have changed, as well as a process to monitor, identify, and remove any undesirable cache entries.

Choosing a Cache Management Strategy

The choice of a cache management strategy depends on the volatility of the data in the underlying databases and the predictability of the changes that cause this volatility. It also depends on the number and types of queries that comprise your cache, as well as the usage those queries receive. This section provides an overview of the various approaches to cache management.

Disable Caching for the System

You can disable caching for the whole system by setting the ENABLE parameter to NO in the NQSConfig.INI file and restarting the Siebel Analytics Server. Disabling caching stops all new cache entries and stops any new queries from using the existing cache. Disabling caching allows you to enable it at a later time without losing any entries already stored in the cache.

Temporarily disabling caching is a useful strategy in situations where you might suspect having stale cache entries but want to verify if they are actually stale before purging those entries or the entire cache. If you find that the data stored in the cache is still relevant, or after you have safely purged problem entries, you can safely reenable the cache. If necessary, purge the entire cache or the cache associated with an entire business model before enabling the cache again.

Caching and Cache Persistence Timing for Specified Physical Tables

You can specify a cachable attribute for each physical table; that is, if queries involving the specified table can be added to the cache to answer future queries. To enable caching for a particular physical table, select the table in the Physical layer of the Siebel Analytics Server Administration Tool and select the option Make table cachable in the General tab of the Physical Table properties dialog box. You can also use the Cache Persistence Time settings to specify how long the entries for this table should persist in the query cache. This is useful for OLTP data sources and other data sources that are updated frequently, potentially down to every few seconds.

Once caching is enabled for a table, any query involving the table is added to the cache. All tables are cachable by default, but some tables may not be good candidates to include in the cache unless you use the Cache Persistence Time settings. For example, perhaps you have a table that stores stock ticker data, which is updated every minute. You could use the Cache Persistence Time settings to purge the entries for that table every 59 seconds.

To disable caching for a particular physical table, select the table in the Physical layer of the Siebel Analytics Server Administration Tool and clear the option Make table cachable in the General tab of the Physical Table dialog box. Once caching is disabled for a table, any query involving the table is not added to the cache.

Configure Siebel Analytics Server Event Polling Tables

Siebel Analytics Server event polling tables store information about updates in the underlying databases. An application (such as an application that loads data into a data mart) could be configured to add rows to an event polling table each time a database table is updated. The Analytics server polls this table at set intervals and invalidates any cache entries corresponding to the updated tables. Event polling tables can be your sole method of cache management or can be used in conjunction with other cache management schemes. For more information on event polling tables, see Setting Up Event Polling Tables on the Physical Databases.


 Siebel Analytics Server Administration Guide 
 Published: 23 June 2003