{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,9,24]],"date-time":"2025-09-24T10:20:13Z","timestamp":1758709213150},"reference-count":26,"publisher":"Association for Computing Machinery (ACM)","issue":"2","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Proc. VLDB Endow."],"published-print":{"date-parts":[[2009,8]]},"abstract":"<jats:p>\n            Large enterprises have been relying on parallel database management systems (\n            <jats:italic>PDBMS<\/jats:italic>\n            ) to process their ever-increasing data volume and complex queries. The scalability and performance of a PDBMS comes from load balancing on all nodes in the system. Skewed processing will significantly slow down query response time and degrade the overall system performance. Business intelligence tools used by enterprises frequently generate a large number of outer joins and require high performance from the underlying database systems. Although extensive research has been done on handling skewed processing for inner joins in PDBMS, there is no known research on data skew handling for parallel outer joins. We propose a simple and efficient outer join algorithm called OJSO (Outer Join Skew Optimization) to improve the performance and scalability of parallel outer joins. Our experimental results show that the OJSO algorithm significantly speeds up query elapsed time in the presence of data skew.\n          <\/jats:p>","DOI":"10.14778\/1687553.1687565","type":"journal-article","created":{"date-parts":[[2014,6,24]],"date-time":"2014-06-24T12:17:57Z","timestamp":1403612277000},"page":"1390-1396","source":"Crossref","is-referenced-by-count":33,"title":["Efficient outer join data skew handling in parallel DBMS"],"prefix":"10.14778","volume":"2","author":[{"given":"Yu","family":"Xu","sequence":"first","affiliation":[{"name":"Teradata, San Diego, CA"}]},{"given":"Pekka","family":"Kostamaa","sequence":"additional","affiliation":[{"name":"Teradata, El Segundo, CA"}]}],"member":"320","published-online":{"date-parts":[[2009,8]]},"reference":[{"key":"e_1_2_1_1_1","volume-title":"HIPC, page 367","author":"Alsabti K.","year":"1998","unstructured":"K. Alsabti and S. Ranka . Skew-insensitive parallel algorithms for relational join . In HIPC, page 367 , 1998 . K. 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Goel, and B. R. Iyer. Simplification of outer joins. In CASCON '95: Proceedings of the 1995 conference of the Centre for Advanced Studies on Collaborative research, page 7. IBM Press, 1995."},{"key":"e_1_2_1_4_1","first-page":"441","volume-title":"ICDE","author":"Bhargava G.","year":"1996","unstructured":"G. Bhargava , P. Goel , and B. R. Iyer . Efficient processing of outer joins and aggregate functions . In ICDE , pages 441 -- 449 , 1996 . G. Bhargava, P. Goel, and B. R. Iyer. Efficient processing of outer joins and aggregate functions. In ICDE, pages 441--449, 1996."},{"key":"e_1_2_1_5_1","doi-asserted-by":"publisher","DOI":"10.1145\/319057.319101"},{"key":"e_1_2_1_6_1","doi-asserted-by":"publisher","DOI":"10.5555\/381992.383618"},{"key":"e_1_2_1_7_1","doi-asserted-by":"publisher","DOI":"10.1145\/129888.129894"},{"key":"e_1_2_1_8_1","volume-title":"VLDB","author":"DeWitt D. J.","year":"1992","unstructured":"D. J. DeWitt , J. F. Naughton , D. A. Schneider , and S. Seshadri . 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Bucket spreading parallel hash: A new, robust, parallel hash join method for data skew in the super database computer (sdc). In VLDB, pages 210--221, 1990."},{"key":"e_1_2_1_16_1","first-page":"445","volume-title":"VLDB","author":"Zhou J.","year":"2005","unstructured":"P.-\u00c5. Larson and J. Zhou . View matching for outer-join views . In VLDB , pages 445 -- 456 , 2005 . P.-\u00c5. Larson and J. Zhou. View matching for outer-join views. In VLDB, pages 445--456, 2005."},{"key":"e_1_2_1_17_1","first-page":"56","volume-title":"ICDE","author":"Zhou J.","year":"2007","unstructured":"P.-\u00c5. Larson and J. Zhou . Efficient maintenance of materialized outer-join views . In ICDE , pages 56 -- 65 , 2007 . P.-\u00c5. Larson and J. Zhou. Efficient maintenance of materialized outer-join views. 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