Query Processing and Optimization
Query Processing and Optimization
Query Processing and Optimization
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<strong>Query</strong> <strong>Optimization</strong><br />
• Aim: Transform query into faster, equivalent query<br />
equivalent query 1<br />
query<br />
equivalent query 2<br />
...<br />
equivalent query n<br />
faster<br />
query<br />
• Heuristic (logical) optimization<br />
• <strong>Query</strong> tree (relational algebra) optimization<br />
• <strong>Query</strong> graph optimization<br />
• Cost-based (physical) optimization<br />
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