Problem With Caching A Report in Answers Using A Script

Answers request causes BI server to crash
July 21, 2009
BI Server Restart
July 27, 2009

The cache is purged but new cache is not created. Customer is not able to cache the reports which contain Database Functions for Columns.
All the cache entries were not created when used a logical query which contains DB functions in it. The query doesn’t get cached and there is no error
produced.
Cache is created when the queries are not using any database functions.

Cause

Queries containing the evaluate function are not qualified to cache. Hence this query is not getting cached. This is expected behavior.
Evaluate is not cacheable because there is no reliable means for OBIEE to interpret the semantics of the string function definition and determine if the
function defined there can be reused under what condition. Take a simple example, Evaluate(‘Today()’ as Date), OBIEE would have no idea this function
returns a result that can be reused till the end of day.

Dynamic repository variables are refreshed by data returned from queries. The same rule applies here. If the query that refreshes the variable is using a
database function and evaluate then the whole query (report) will not be cached as the value of the variable cannot be cached.
If the query that refreshes the variable does not use database functions then it is cached and the report should be cached.
However, when the value of a dynamic repository variable changes, all cache entries associated with a business model that reference the value of the variable,
are purged automatically.

If you see the query in the Cache Manager then it means that is cached. You can check if that particular cached query is used or not by checking the “Last
used” column after the user ran the report. The cache should be used and the value of the “Last Used” column should be updated and different from the value
of the “Created” column.

Solution
Using iBots is an alternative. If you schedule the reports they should appear in the cache until the cache is purged. Keep in mind that reports having the
database functions and evaluate will not be cached either. Also, reports having dynamic repository variables will automatically be purged when the variable
changes.
The iBot should not include queries with database functions and evaluate in order to be cached.

1 Comment

  1. lou yang says:

    Thanks… that’s why the cache not work…. sign.. need to change my report

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