Product overview > Cache > Database integration



Sparse and complete cache

WebSphere eXtreme Scale can be used as a sparse cache or a complete cache. A sparse cache only keeps a subset of the total data, while a complete cache keeps all of the data. and can be populated lazily, on-demand. Sparse caches are normally accessed using keys (instead of indexes or queries) since the data is only partially available.

When a key is not present (a cache miss), the next tier is invoked and the data is fetched and inserted into the respective cache tier. If using a query or index, only the currently loaded values are accessed and the requests are not forwarded to the other tiers. A complete cache contains all of the required data and can be accessed using non-key attributes with indexes or queries.

A complete cache is preloaded with data prior to applications' using it, and can effectively function as a database replacement. After data is loaded, it can be treated similarly to a database. Since all of the data is available, queries and indexes can be used to find and aggregate data.


Parent topic:

Database integration: Write-behind, in-line, and side caching


Related concepts

Side cache and in-line cache

In-line caching

Write-behind caching

Loaders

Data pre-loading and warm-up

Map preloading

Database synchronization techniques

Invalidate stale cache data

Indexing