Patent ID: 6944633
Filing Date: 2005-09-13
Classification: G06F,Y10S

Abstract:
1. A computer-implemented method of performing a join in a partitioned database system, the method comprising: identifying a join that identifies a first table and a second table, the first table including a plurality of first table rows, each of the plurality of first table rows grouped into one of a plurality of first table partitions, the second table including one or more second table rows, each of the plurality of second table rows grouped into one or more second table partitions; determining that the first table and the second table are joined on equality constraints; and joining the one or more first table rows with the one or more second table rows using a rowkey merge join where equality exists; wherein joining the one or more first table rows with the one or more second table rows using the rowkey merge join comprises: a) identifying a rowkey associated with a first qualifying row in the first table, the first qualifying row in the first table comprising the first row in the first table that satisfies any conditions of the join, the rowkey comprising a partition number and a rowhash associated with the first row in the first table; b) determining whether the rowkey associated with the first row in the first table matches a rowkey associated with a row in the second table; c) identifying a rowkey associated with the next qualifying sequential row in the second table; d) determining whether the rowkey associated with the next qualifying sequential row in the second table matches a rowkey associated with a row in the first table; e) repeating b)–d) until each qualifying row in the first table and each qualifying row in the second table is considered.