Data Compression for Analytics over Large-scale In-memory Column   Databases
  Data compression schemes have exhibited their importance in column databases by contributing to the high-performance OLAP (Online Analytical Processing) query processing. Existing works mainly concentrate on evaluating compression schemes for disk-resident databases as data is mostly stored on disks. With the continuously decreasing of the price/capacity ratio of main memory, it is the tendencies of the times to reside data in main memory. But the discussion of data compression on in-memory databases is very vague in the literature. In this work, we present an updated discussion about whether it is valuable to use data compression techniques in memory databases. If yes, how should memory databases apply data compression schemes to maximize performance? 
Chunbin Lin, Jianguo Wang, Yannis Papakonstantinou
cs.DB