| 主权项 |
1. A computer implemented method for performing a partitioned join, the method comprising:
determining, by one or more computer processors, a first data table and a second data table to be joined, wherein the first data table and the second data table have a join attribute, and wherein data blocks of the first data table are stored on a storage device; determining, by one or more computer processors, an attribute value information of the join attribute for the data blocks of the first data table; defining, by one or more computer processors, at least one partition for the first data table and the second data table using at least the attribute value information on the join attribute, wherein each partition of the at least one partition has a respective partition range of values of the join attribute; and processing, by one or more computer processors, a pair wise partition join on a first partition range of the determined partition ranges comprising:
determining, by one or more computer processors, a first data blocks of the first data table that fully fall under the first partition range using the attribute value information, reading the determined first data blocks from a disk into a memory and feeding the determined first data blocks to the partition join on the first partition range with the second data table; anddetermining, by one or more computer processors, a second data blocks of the first data table that partially fall under the first partition range using the attribute value information and selectively feeding records of the determined second data blocks that fall under the first partition range to the processing of the first partition range with the second data table. |
