How Zoomdata Caches Data
Zoomdata uses different caching methods for the different types of data with which it works:
- For aggregated result sets, Zoomdata leverages Spark to cache aggregated result data. See How Zoomdata Uses Apache Spark.
- For streaming data, the result data is cached and persisted in PostgreSQL.
- A Zoomdata visualization cache is used to enhance performance in scenarios where large numbers of users are concurrently viewing the same shared visualizations.
|Cached data is shared between users only if they have the same data access permissions and security context.|
|When caching is enabled, Zoomdata does not requery the data source to obtain the data unless the cache is cleared or unless a refresh schedule is defined in the data source configuration. Read about the Refresh Tab and Using the Zoomdata Scheduler.|
By default, data caching is enabled for all data sources. The Zoomdata cache stores all the results of aggregated requests from your data source. When a chart is created the request is first sent to the Zoomdata cache. If the required results are found in the data cache, they are visualized on your chart.
If the required results are not found in the Zoomdata data cache, the data flow is as follows:
The request is sent to the Zoomdata cache.
When the required results are not found in the Zoomdata data cache, the request is sent to the data source.
The results from the data source are sent to the Zoomdata data cache and stored there.
The chart displays the requested data.
Review the following links to learn how you can control Zoomdata data caching.
- Clearing the Cache for a Data Source Configuration
- Disabling Data Caching for a Data Source
- Using the Zoomdata Scheduler
You can force Zoomdata to bypass the visualization cache and query the underlying data source by selecting Refresh All from a Zoomdata dashboard menu.