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How Caching Works with Denodo?

Hi, How Denodo Cache the data when fetching it from Data Source? What's the Space it consume while caching? What's the retention period of Cache, when it flushes the Cache? Can we define the data that needs to be fully cache, partial cache or no cache? When downstream systems are fetching data, does it fetch from the Cache or from the Data Source?
user
22-06-2022 19:45:43 -0400

1 Answer

Hello, Denodo includes a cache functionality which stores data locally once queried from the actual datasource, thus reducing the need to read data from source every time. Reference : [Cache Module](https://community.denodo.com/docs/html/browse/8.0/en/vdp/administration/cache_module/cache_module) Caching is done with the RDBMS principles on a database. By default it uses an internal Derby database deployed on the same server as VDP. But it is recommended to use an appropriate external database for caching the data. The lifecycle of cached data depends on the configurations done while defining the cache for the particular view. The Time to live defines the lifetime of a cache and the Maintenance task then deletes expired records. Reference : [Configuring the Cache](https://community.denodo.com/docs/html/browse/8.0/en/vdp/administration/server_configuration/configuring_the_cache/configuring_the_cache) The cache modes can be defined at a view level to determine whether to store the cache with Full or Partial mode. Caching can be disabled for a particular view as well. Reference : [Cache Modes](https://community.denodo.com/docs/html/browse/8.0/en/vdp/administration/cache_module/cache_modes/cache_modes) Once defined and executed, any further query would first attempt to fetch data from the cache. And depending on the cache mode defined, it could check the original data source if required. I would also check the useful [best practices](https://community.denodo.com/kb/en/view/document/Best%20Practices%20to%20Maximize%20Performance%20III%3A%20Caching) guide for more information and guidance. Hope this helps.
Denodo Team
23-06-2022 11:39:24 -0400
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