发明名称 |
SYSTEM, METHOD, AND COMPUTER-READABLE MEDIUM FOR OPTIMIZING PROCESSING OF DISTINCT AND AGGREGATION QUERIES ON SKEWED DATA IN A DATABASE SYSTEM |
摘要 |
A system, method, and computer-readable medium for optimization of query processing in a parallel processing system are provided. Skewed values and non-skewed values are treated differently to improve upon conventional DISTINCT and aggregation query processing. Skewed attribute values on which a DISTINCT selection or group by aggregation is applied are allocated entries in a hash table. In this manner, a processing module may consult the hash table to determine if a skewed attribute value has been encountered during the query processing in a manner that precludes repetitive redistribution of rows with highly skewed attribute values on which a DISTINCT selection or group by aggregation is applied.
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申请公布号 |
US2010131540(A1) |
申请公布日期 |
2010.05.27 |
申请号 |
US20080277343 |
申请日期 |
2008.11.25 |
申请人 |
XU YU;KOSTAMAA OLLI PEKKA |
发明人 |
XU YU;KOSTAMAA OLLI PEKKA |
分类号 |
G06F17/30;G06F7/00 |
主分类号 |
G06F17/30 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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