tailieunhanh - LogBase: A Scalable Log-structured Database System in the Cloud

The link between pesticides and cancer has long been a concern. While agriculture has traditionally been tied to pesticide-related illnesses, 19 of 30 commonly used lawn pesticides and 28 of 40 commonly used school pesticides are linked to cancer. Even with the growing body of evidence linking environmental exposures to cancer in recent years, a report released May 6, 2010 by the President’s Cancer Panel finds that the true burden of environmentally- induced cancer is greatly underestimated. The Panel’s report, Reducing Environmental Cancer Risk: What We Can Do Now, concludes that while environmental exposure is not a new front on. | LogBase A Scalable Log-structured Database System in the Cloud Hoang Tam Vo 1 Sheng Wang 2 Divyakant Agrawal t3 Gang Chen 4 Beng Chin Ooi 5 National University of Singapore University of California Santa Barbara Zhejiang University 1 2 5 voht wangsh ooibc @ 3agrawal@ 4cg@ ABSTRACT Numerous applications such as financial transactions . stock trading are write-heavy in nature. The shift from reads to writes in web applications has also been accelerating in recent years. Write-ahead-logging is a common approach for providing recovery capability while improving performance in most storage systems. However the separation of log and application data incurs write overheads observed in write-heavy environments and hence adversely affects the write throughput and recovery time in the system. In this paper we introduce LogBase - a scalable log-structured database system that adopts log-only storage for removing the write bottleneck and supporting fast system recovery. It is designed to be dynamically deployed on commodity clusters to take advantage of elastic scaling property of cloud environments. LogBase provides in-memory multiversion indexes for supporting efficient access to data maintained in the log. LogBase also supports transactions that bundle read and write operations spanning across multiple records. We implemented the proposed system and compared it with HBase and a disk-based log-structured record-oriented system modeled after RAMCloud. The experimental results show that LogBase is able to provide sustained write throughput efficient data access out of the cache and effective system recovery. 1. INTRODUCTION There are several applications that motivate the design and implementation of LogBase such as logging user activity . visit click or ad click from high volume web sites and financial transactions . stock trading . The desiderata for the backend storage systems used in such write-heavy applications include High