Clearing Query and Dashboards Caches
Birst has two caches, query and dashboards, that improve system performance. In some cases you may need to clear one or both of them.
The query cache, also called the results cache, caches the results of database queries. It contains the results of queries keyed by the logical query with which it is associated. There are three types of query caches: memory (per server, limited to small result sets, < 1000 rows), exact disk (shared across all servers), and inexact disk (shared across all servers). All queries against the data store (warehouse) or Live Access go through the query cache. The query cache improves dashboard response since the base query results are cached across multiple users accessing them. In the Query Admin UI, you can clear all the cached queries for a space or for just a specific query. For a discussion of queries see the Community post The Secret Life of Queries.
The dashboards cache contains information about what users have access to what dashboards. It is a cache of which pages each user is allowed to see based on their group membership. In the cases where there are a large number of dashboards with complex permissions, the dashboards cache improves performance.
Tip: The browser cache is not cleared using these commands. It is a best practice for users to also clear their browser cache using the relevant action for their particular browser.
Alternatives: Instead of manually using the UI, you can use the clearcache command in the Command Window to clear both the query and dashboard caches for a space at once.
When to Clear the Dashboard Cache
Space Administrators may need to clear the dashboards cache when:
- Different users are using multiple versions of the product. For example, you are editing a dashboard in 5.21 and the change is not propagating to users on 5.20.
- You make changes to a dashboard and do not see the saved changes you have made.
- You switch between Birst release versions, such as when comparing releases for testing purposes.
For suggestions about managing the dashboard cache, see the Community post Caching and Rendering Pages and Reports.
When to Clear the Query Cache
For a Birst data store (warehouse) space, the query cache is set to never expire and automatically clears when the metadata (dimensions, hierarchies, measures, etc.) changes or when data is processed. An exception is for queries using the Birst Time.*Ago attributes where the expiration is based upon the boundary for the *Ago attribute (end of the day, end of the week, etc.)
For Live Access spaces, Space Administrators control the life of the cache using both the time-to-live (TTL) settings and clear cache features. The default cache expiration date is based upon the minimum value for the TTL for all tables in the query.
Space Administrators may need to clear the query cache when:
- Live Access data is updated. Clear the cache so that data can be refreshed from the source.
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The system does not seem to catch that a dashboard or permission has been changed.
To clear the caches from the Query Admin UI
1. | Go to Admin - Define Sources - Query Admin. |
2. | Click the Cache tab. |
3. | Select one of the following: |
Clear All Query Caches.
Clear Dashboards Cache.
Clear Cache for Query: Type or paste a query in the text box at the top, then click this button.
See Also
Running a Logical Query