|   | CMU-CS-03-124 Computer Science Department
 School of Computer Science, Carnegie Mellon University
 
    
     
 CMU-CS-03-124
 
Lachesis: Robust Database Storage ManagementBased on Device-specific Performance Characteristics
 
Jiri Schindler, Anastassia Ailamaki, Gregory R. Ganger 
March 2003  
To appear in a revised form in theProceedings of the Conference on Very Large Databases,
 VLDB03, Berlin, Germany, September 9-12, 2003.
 CMU-CS-03-124.ps
 CMU-CS-03-124.pdf
 Keywords: Database storage management, performance evaluation
 Database systems work hard to tune I/O performance, but they do not 
always achieve the full performance potential of modern disk drives. 
Their abstracted view of storage components hides useful 
device-specific characteristics, such as disk track boundaries and 
advanced built-in firmware algorithms. This paper presents a new 
storage manager architecture, called Lachesis, that exploits a few 
observable device-specific characteristics to achieve more robust 
performance. Most notably, it enables efficiency nearly equivalent to 
sequential streaming even in the presence of competing I/O traffic. 
With automatic adaptation to device characteristics, Lachesis simplifies 
manual configuration and restores optimizer assumptions about the 
relative costs of different access patterns expressed in query plans. 
Based on experiments with both IBM DB2 and an implementation inside 
the Shore storage manager, Lachesis improves performance of TPC-H 
queries on average by 10% when running on dedicated hardware. More 
importantly, it speeds up TPC-H by up to 3X when running concurrently 
with an OLTP workload, which is simultaneously improved by 7%.
 
21 pages 
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