Sideways Information Passing for Push-Style Query Processing

In many modern data management settings, data is queried from a central node or nodes, but is stored at remote sources. In such a setting it is common to perform "pushstyle" query processing, using multithreaded pipelined hash joins and bushy query plans to compute parts of the query in parallel; to avoid idling, the CPU can switch between them as delays are encountered. This works well for simple select-projectjoin queries, but increasingly, Web and integration applications require more complex queries with multiple joins and even nested subqueries. As we demonstrate in this paper, push-style execution of complex queries can be improved substantially via sideways information passing; push-style queries provide many opportunities for information passing that have not been studied in the past literature. We present adaptive information passing, a general runtime decision-making technique for reusing intermediate state from one query subresult to prune and reduce computation of...

• Type: Conference
• Year: 2008
• Where: ICDE
• Authors: Zachary G. Ives, Nicholas E. Taylor
• Keywords: Bushy Query Plans, Complex Queries, Database, ICDE 2008, Information Passing