---
title: The Inline Cache
---
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An inline cache holds region entries for a client application.

## Description of an Inline Cache

A cache is formed from a region within a <%=vars.product_name%> cluster,
and the cache sits between the client application and a
backing data store.

<img src="../images/inline-cache.png" id="inline-cache-png" class="image" />

The client application's cache lookup is a region get
operation, and a cache write is a region put operation. 

When the cache (region) has the requested region entry,
it quickly responds with the value for a lookup operation.
This is a cache hit.
If the requested region entry is not in the region,
it is a cache miss,
and code that has been deployed to the server acquires the
entry from the data store.
The acquired region entry is written to the region
such that future lookups will cause a cache hit.

## Implementation and Configuration