Least expected cost query optimization: an exercise in utility

Details Least expected cost query optimization: an exercise in utility Least expected cost query optimization: an exercise in utility

1999-09-21

arxiv.org/abs/cs/9909016v1

Computer Science

Databases

This paper appears in Proceedings of the Eighteenth Annual ACM Symposium on Principles of Database Systems, 1999, pp. 138--147

Scientific paper

We identify two unreasonable, though standard, assumptions made by database query optimizers that can adversely affect the quality of the chosen evaluation plans. One assumption is that it is enough to optimize for the expected case---that is, the case where various parameters (like available memory) take on their expected value. The other assumption is that the parameters are constant throughout the execution of the query. We present an algorithm based on the ``System R''-style query optimization algorithm that does not rely on these assumptions. The algorithm we present chooses the plan of the least expected cost instead of the plan of least cost given some fixed value of the parameters. In execution environments that exhibit a high degree of variability, our techniques should result in better performance.

Affiliated with

Also associated with

No associations

Rating

Least expected cost query optimization: an exercise in utility does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Least expected cost query optimization: an exercise in utility, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Least expected cost query optimization: an exercise in utility will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-153222