A Partial Histogram Maintenance Mode

Abstract

Although histogram has been introduced into the optimizer of the relational database to assist cardinality estimates for more than thirty years, the issue of histogram maintenance is not addressed well. The application of the query feedback information provides a new way of thinking for the histogram maintenance. But it is not mature until now and inefficiency is the main problem. The query feedback-based histogram maintenance approach adopts the entire update mode and the whole histogram will be updated in each maintenance process. This mode brings huge computation for the maintenance process and becomes the most important reason for its inefficiency. Therefore, we propose the partial update mode in this paper to replace the entire update mode and try to improve the maintenance efficiency by limiting the updating range and decreasing the computation in each maintenance process.