DaC scan: a novel scan operator for exploiting SSD internal parallelism
Namom Alencar, Ângelo Brayner, Jose Aguiar Filho, Hamilton Lopes · Concurrency and Computation Practice and Experience · 2016
Summary Solid‐state drives (SSDs) have become an attractive alternative for storing large databases. Solid‐state drives do not present mechanical parts in their assembly. Consequently, SSDs have different characteristics and capabilities than magnetic disks Hard Disk Drives (HDDs). One of the most important features of SSDs is the fact that they implement different levels of internal parallelism for executing read/write operations. In database query processing, the table scan operator is responsible for reading an entire table. Generally, a scan operator is utilized whenever there is no index defined on the table to be accessed. This paper introduces a novel scan operator, denotedDaC Scan, for reading database tables stored in SSDs. The key goal of the proposed operator is to explore IO parallelism. Thus, the idea is to makeDaC Scanable to read different regions of a single table simultaneously. For validation ofDaC Scanefficiency, experiments with a prototype have been conducted over the TPC‐H benchmark database, scale factors 10 and 20. The results show thatDaC Scanis efficient, presenting significant gains w.r.t. classical scan operators.