Adaptive query parallelization in multi-core column stores

With the rise of multi-core CPU platforms, their optimal utilization for in-memory OLAP workloads using column store databases has become one of the biggest challenges. Some of the inherent limi- tations in the achievable query parallelism are due to the degree of parallelism dependency on the data skew, the overheads incurred by thread coordination, and the hardware resource limits. Finding the right balance between the degree of parallelism and the multi-core utilizati

Stethoscope: A platform for interactive visual analysis of query execution plans

Searching for the performance bottleneck in an execution trace is an error prone and time consuming activity. Existing tools oer some comfort by providing a visual representation of trace for analysis. In this paper we present the Stethoscope, an interactive visual tool to inspect and analyze columnar database query performance, both online and online. It's unique interactive animated interface capitalizes the large dataflow graph representation of a query execution plan, augmented with query execution trace information. We demonstrate features of Stethoscope for both online and online analysis of long running queries. It helps in understanding where time goes, how optimizers perform, and how parallel processing on multi-core systems is exploited

Exploring employment opportunities through microtasks via cybercafes

Microwork in cybercafés is a promising tool for poverty alleviation. For those who cannot afford a computer, cybercafés can serve as a simple payment channel and as a platform to work. However, there are questions about whether workers are interested in working in cybercafés, whether cybercafé owners are willing to host such a set up, and whether workers are skilled enough to earn an acceptable pay rate? We designed experiments in internet/cyber cafes in India and Kenya to investigate these issues. We also investigated whether computers make workers more productive than mobile platforms? In surveys, we found that 99% of the users wanted to continue with the experiment in cybercafé, while 8 of 9 cybercafé owners showed interest to host this experiment. User typing speed was adequate to earn a pay rate comparable to their existing wages, and the fastest workers were approximately twice as productive usi