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| <?xml version="1.0"?> |
| |
| <document> |
| <properties> |
| <title>Berkeley DB Disk Auxiliary Cache</title> |
| <author email="ASmuts@yahoo.com">Aaron Smuts</author> |
| </properties> |
| |
| <body> |
| <section name="Berkeley DB Disk Auxiliary Cache"> |
| <p> |
| The Berkeley DB Disk Auxiliary Cache is an optional plugin for the |
| JCS. It is primarily intended to provide a secondary store to |
| ease the memory burden of the cache. When the memory cache |
| exceeds its maximum size it tells the cache hub that the item |
| to be removed from memory should be spooled to disk. The cache |
| checks to see if any auxiliaries of type "disk" have been |
| configured for the region. If the "Berkeley DB Disk Auxiliary Cache" |
| is used, the item will be spooled to disk. |
| </p> |
| <p> |
| The Berkeley DB is far slower than the Indexed Disk Cache, especially for puts. |
| This is partially due to the fact that the BDB store its keys on disk. |
| However, any items stored in the BDB will be available on restart, even if |
| the cache is not shutdown properly. |
| </p> |
| <p> |
| The Berkeley DB requires jdk1.4 and above. As such, it is distributed |
| in the jdk14-ext jar. |
| </p> |
| |
| <subsection name="Configuration"> |
| <p> |
| The configuration is simple and is done in the auxiliary |
| cache section of the <code>cache.ccf</code> configuration file. |
| In the example below, I created a Berkeley DB Auxiliary Cache |
| referenced by <code>BDBDC</code>. It uses files located in the |
| "DiskPath" directory. |
| </p> |
| |
| <source><![CDATA[ |
| # ############################################################# |
| # #### Default Region Configuration |
| jcs.default=BDBDC |
| jcs.default.cacheattributes=org.apache.commons.jcs.engine.CompositeCacheAttributes |
| jcs.default.cacheattributes.MaxObjects=100 |
| jcs.default.cacheattributes.MemoryCacheName=org.apache.commons.jcs.engine.memory.lru.LRUMemoryCache |
| |
| # ############################################################# |
| # #### CACHE REGIONS |
| jcs.region.myRegion1=BDBDC |
| jcs.region.myRegion1.cacheattributes=org.apache.commons.jcs.engine.CompositeCacheAttributes |
| jcs.region.myRegion1.cacheattributes.MaxObjects=1000 |
| jcs.region.myRegion1.cacheattributes.MemoryCacheName=org.apache.commons.jcs.engine.memory.lru.LRUMemoryCache |
| |
| # ############################################################# |
| # #### AUXILIARY CACHES |
| # Berkeley DB JE |
| jcs.auxiliary.BDBDC=org.apache.commons.jcs.auxiliary.disk.bdbje.BDBJECacheFactory |
| jcs.auxiliary.BDBDC.attributes=org.apache.commons.jcs.auxiliary.disk.bdbje.BDBJECacheAttributes |
| jcs.auxiliary.BDBDC.attributes.DiskPath=target/ |
| jcs.auxiliary.BDBDC.attributes.MaxPurgatorySize=100000 |
| ]]></source> |
| </subsection> |
| |
| </section> |
| </body> |
| </document> |
