How to purge the Query Cache
For the Presentation Server cache, see Cache
To disable completly the query cache, you must set to the ENABLE cache parameter the value NO in the file nqsconfig.
[CACHE]
ENABLE = NO;
For one session, you have to set the session system variable with the value 1:
For one session, you have to set this request variables with the value 1:
Example in the advanced tab of an answer :
SET VARIABLE DISABLE_CACHE_HIT=1;
Note : Replace OracleBI_Home by your own directory.
Create a file PurgeAllCache.sql and add the SAPurgeAllCache ODBC Function :
{call SAPurgeAllCache()};
And save it in a directory (for instance OracleBI_Home\Cache).
Then from a command dos, call nqcmd with this statement :
OracleBI_Home\server\Bin\nqcmd.exe -d AnalyticsWeb -u Administrator -p Password
-s "OracleBI_Home\Cache\PurgeAllCache.sql" -o "OracleBI_Home\Cache\PurgeAllCache.log"
You will retrieve then in the PurgeAllCache.log :
{call SAPurgeAllCache()}
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RESULT_CODE RESULT_MESSAGE
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1 [59118] Operation SAPurgeAllCache succeeded!
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Row count: 1
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Processed: 1 queries
You can also use the ODBC Bi Server cache Function in a script that can call the job manager.
When failed:
call SAPurgeAllCache()
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RESULT_CODE RESULT_MESSAGE
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59115 [59115] Operation not performed because caching is not enabled.
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Row count: 1
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In the Server Administration Guide, section “Understanding and Creating Repository Variables”, you can read that :
When the value of a dynamic repository variable changes, all cache entries associated with a business model that
reference the value of that variable will be purged automatically.
This means that the query cache will be purged when the variable is refreshed. By creating a Dynamic Repository Variable that selects a specific value from a table you can easily easily trigger a cache purge.
For instance, from an ETL process :
The use of an Oracle BI Server event polling table (event table) is a way to notify the Oracle BI Server that one or more physical tables have been updated. The Oracle BI Server cache system reads rows from, or polls, the event table, extracts the physical table information from the rows, and purges stale cache entries that reference those physical tables.
More … OBIEE 10G/11G - Event Pooling table (Event Table) to purge the cache after ETL process
You can purge the cache automatically for a particular table, by setting the Cache Persistence Time field in the Physical Table.