Patent ID: 9141666
Filing Date: 2015-09-22
Classification: G06F

Abstract:
1. A computer-implemented method for updating statistics used by a query optimizer of a database system, the query optimizer determining an execution plan used to return data for a query, wherein the execution plan is determined from statistics for data in the database system, and the computer-implemented method controlling how statistics used by the query optimizer are updated so as to conserve computing resources otherwise used to update the statistics for the data, the computer-implemented method being performed by one or more processors executing computer executable instructions for the computer-implemented method, and the computer-implemented method comprising acts of: storing one or more data tables in a database, at least some of the data tables comprising partitions which define disjoint data ranges of data that do not overlap as between data ranges of the at least some data tables; at least some of the disjoint data ranges having corresponding statistics information stored in a repository of the database; accessing the stored statistics information of the database, and organizing the accessed statistics by generating a statistics tree structure having performing one or more statistics tree transformation operations that transform the statistics tree structure into a form in which the number and arrangement of nodes designed to optimize the statistics tree structure in a manner that conserves computing resources used when updating the statistics used by the query optimizer to generate an execution plan for a received query, the transformation operations for the statistics tree comprising at least one of the following: updating only those statistics corresponding to nodes of the statistics tree structure where a change has occurred which results in changes to one or more of the disjoint data ranges of data for the at least some data tables of the database.