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From "Gokul Soundararajan (JIRA)" <derby-...@db.apache.org>
Subject [jira] Created: (DERBY-1437) Add new LRU Cache Manager
Date Thu, 22 Jun 2006 12:38:31 GMT
Add new LRU Cache Manager
-------------------------

         Key: DERBY-1437
         URL: http://issues.apache.org/jira/browse/DERBY-1437
     Project: Derby
        Type: Improvement

  Components: Services  
    Reporter: Gokul Soundararajan
 Assigned to: Gokul Soundararajan 


In databases, caching plays an important role in performance. To obtain high performance,
we need to cache pages from disk in memory to reduce access time. The problem stated is that
the existing replacement algorithm performs poorly so we need to research new algorithms for
page replacement and implement it in Apache Derby. The benefit of a better algorithm is improved
performance.

In this project, I first have to look at existing work to quantify the different replacement
algorithms used in databases. I have run simulation experiments on several cache replacement
algorithms from FIFO, Clock, Clock-Pro, TwoQueue, CAR, and CART. CAR/CART are patented by
IBM so we cannot implement them in Derby. Two Queue has a large synchronization overhead (seen
by Postgres community). Clock-Pro performs well and is being implemented in Linux. Oystein
and I have agreed to implement Clock-Pro inside Derby. See the wiki for more details and simulation
results: http://wiki.apache.org/db-derby/DerbyLruCacheManager

I will implement it in Derby. In addition, I will implement unit tests. Finally, I will perform
experiments showing the benefit of the new algorithm over the existing algorithm. 

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