11 2013 档案

摘要:Tuning MethodologyWhen dealing with performance problems, database professionals tend to focus on the technical aspects of the system, such as resource queues, resource utilization, and so on. However, users perceive performance problems simply as waitsthey make a request and have to wait to get the 阅读全文
posted @ 2013-11-27 17:29 Alex Tian 阅读(315) 评论(0) 推荐(0) 编辑
摘要:Summary DescriptionThe SQL language is spoken by most database experts, and all relational database products include some dialect of the SQL standard. Nevertheless, each product has its own particular query-processing mechanism. Understanding the way a database engine processes queries helps softwar 阅读全文
posted @ 2013-11-26 15:36 Alex Tian 阅读(173) 评论(0) 推荐(0) 编辑
摘要:Logical Query Processing Phases Summary(8) SELECT (9) DISTINCT (11) (1) FROM (3) JOIN (2) ON (4) WHERE (5) GROUP BY (6) WITH {CUBE | ROLLUP}(7) HAVING (10) ORDER BY Brief Description of Logical Query Processing Phases Don't worry too much if the description of the steps doesn't seem ... 阅读全文
posted @ 2013-11-25 17:45 Alex Tian 阅读(297) 评论(0) 推荐(0) 编辑

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