Network Deployment (Distributed operating systems), v8.0 > Administer applications and their environment > Administer Dynamic caching > Administer the dynamic cache service


Use the dynamic cache service


Overview

Use the dynamic cache service to improve application performance by caching the output of servlets, web services, and WAS commands into memory.

The dynamic cache service is enabled by default.

Before configuring, define a cache policy for your application, defining rules for...

To configure the dynamic cache service...


Set cache policy using cachespec.xml

This example puts all of the steps together for configuring the dynamic cache service with the cachespec.xml file, showing the use of the cache ID generation rules, dependency IDs, and invalidation rules.

Suppose that a servlet manages a simple news site. This servlet uses the query parameter "action" to determine if the request views (query parameter "view") news or updates (query parameter "update") news (used by the administrator). Another query parameter "category" selects the news category. Suppose that this site supports an optional customized layout stored in the user's session using the attribute name "layout". Here are example URL requests to this servlet:

The following steps illustrate how to configure the dynamic cache service for this example with the cachespec.xml file:

  1. Define the <cache-entry> elements that are necessary to identify the servlet. In this case, the URI for the servlet is "newscontroller", so this is the cache-entry <name> element. Because this example caches a servlet or JSP file, the cache entry class is "servlet". 
    <cache-entry>
    <name> /newscontroller </name>
    <class>servlet  </class>
</cache-entry>

  2. Define cache ID generation rules. This servlet caches only when action=view, so one component of the cache ID is the parameter "action" when the value equals "view". The news category is also an essential part of the cache ID. The optional session attribute for the user's layout is included in the cache ID. The cache entry is now: 
    <cache-entry>

    <name> /newscontroller </name>
    <class>servlet  </class>

    <cache-id>
        <component id="action" type="parameter">
            <value>view </value>
            <required>true </required>
        </component>
        <component id="category" type="parameter">
            <required>true </required>
        </component>
        <component id="layout" type="session">
            <required>false </required>
        </component>
    </cache-id>
</cache-entry>

  3. Define dependency ID rules.

    For this servlet, a dependency ID is added for the category. Later, when the category is invalidated due to an update event, all views of that news category are invalidated. Following is an example of the cache entry after adding the dependency ID: 

    <cache-entry>

    <name>newscontroller </name>
    <class>servlet  </class>

    <cache-id>
        <component id="action" type="parameter">
            <value>view </value>
            <required>true </required>
        </component>
        <component id="category" type="parameter">
            <required>true </required>
        </component>
        <component id="layout" type="session">
            <required>false </required>
        </component>
    </cache-id>

    <dependency-id>category
        <component id="category" type="parameter">
            <required>true </required>
        </component>
    </dependency-id>

</cache-entry>

  4. Define invalidation rules.

    Because a category dependency ID is already defined, define an invalidation rule to invalidate the category when action=update.

    To incorporate the conditional logic, add "ignore-value" components into the invalidation rule. These components do not add to the output of the invalidation ID, but only determine whether or not the invalidation ID creates and runs. The final cache-entry now looks like the following: 

    <cache-entry>
  
    <name>newscontroller </name>
    <class>servlet  </class>

    <cache-id>
        <component id="action" type="parameter">
            <value>view </value>
            <required>true </required>
        </component>
        <component id="category" type="parameter">
            <required>true </required>
        </component>
        <component id="layout" type="session">
            <required>false </required>
        </component>
    </cache-id>

    <dependency-id>category
        <component id="category" type="parameter">
            <required>true </required>
        </component>
    </dependency-id>

    <invalidation>category

        <component id="action" type="parameter" ignore-value="true">
            <value>update </value>
            <required>true </required>
        </component>

        <component id="category" type="parameter">
            <required>true </required>
        </component>

    </invalidation>

</cache-entry>


What to do next

You might want to enable dynamic cache disk offload. This option moves cache entries that are expired from memory to disk for potential future access. Refer to the Configuring dynamic cache disk offload for more information about enabling disk offload.


Related

Dynamic cache service settings
Configure servlet caching
Configure portlet fragment caching
Configure portlet fragment caching with wsadmin.sh
Configure caching for Struts and Tiles applications
Configure dynamic cache disk offload
Configure Edge Side Include caching
Configure external cache groups
Configure servlet caching
Configure cache replication
Task overview: Using the dynamic cache service to improve performance
Use the DistributedMap and DistributedObjectCache interfaces for the dynamic cache
Configure cacheable objects with the cachespec.xml file

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