[DERBY-1437] Add new LRU Cache Manager

• Type: Improvement
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Component/s: Services
• Assignee: Unassigned
• Reporter: Gokul Soundararajan
• Created: 22/Jun/06 19:37
• Updated: 15/Jun/11 12:43

Description

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.