Patent ID: 8392406
Filing Date: 2013-03-05
Classification: G06F

Abstract:
1. A computer-implemented method comprising: providing in a computer, a table in a database which uses tables to store information, the table comprising a first plurality of rows in a first partition and a second plurality of rows in a second partition; providing in the computer, a first partition-level height-balanced histogram of the first plurality of rows in the first partition of the table; providing in the computer, a second partition-level height-balanced histogram of the second plurality of rows in the second partition of the table; and combining in the computer, at least the first and second partition-level height-balanced histograms to generate and store in a memory of the computer, a third table-level height-balanced histogram for the table; wherein the third table-level height-balanced histogram comprises multiple buckets; and wherein a first count of rows, in a bucket among the multiple buckets in the third table-level height-balanced histogram, is determined by use of at least N/m, N being total number of rows in the table and m being a second count of the multiple buckets in the third table-level height-balanced histogram.