Campbell Fraser

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Query optimizers depend heavily on statistics representing column distributions to create efficient query plans. In many cases, though, statistics are outdated or non-existent, and the process of refreshing statistics is very expensive, especially for ad-hoc workloads on ever bigger data. This results in suboptimal plans that severely hurt performance. The(More)
SQL Server 2012 introduced two innovations targeted for data warehousing workloads: column store indexes and batch (vectorized) processing mode. Together they greatly improve performance of typical data warehouse queries, routinely by 10X and in some cases by a 100X or more. The main limitations of the initial version are addressed in the upcoming release.(More)
Reliable query optimization greatly depends on accurate Cardinality Estimation (CE), which is inherently inexact as it relies on statistical information. In commercial database systems, cardinality estimation models are sophisticated components that over years of development can become very complex. The code that implements cardinality estimation models,(More)
This paper reports a case study on the facilitations of online student group work assignment within on-campus and distance education. There is prior research that explores the use of technology for distance education. However, research that explores how to facilitate distance education group work assignment through the use of technology is limited. Being(More)
What kind of knowledge activities are required in order for students to conduct online group work activities successfully in distance education? This paper reports on the knowledge activities involved within online group work in distance education. It explains the types of knowledge used in these activities. The research is a qualitative case study set(More)