In the Real-World Performance Roundtable, Part 2: The Optimizer, Schema Statistics, SQL Tuning at Oracle OpenWorld 2006, I worked an example of how the optimizer can have difficulty estimating the correct cardinality when there is data correlation. (The Zodiac example can be found on pages 46-49 of the presentation.) In Oracle 11g, there has...
The other day I was reading the 11g Database VLDB and Partitioning Guide and came across the below execution plan for a partial partition-wise join between sales and customers. --------------------------------------------------------------------------- | Id | Operation | Name | Pstart| Pstop | --------------------------------------------------------------------------- | 0 | SELECT STATEMENT | | | | | 1 | PX...
Recently, I’ve been quite busy with performance projects and haven’t had the spare time I would like to keep up on my blog. Now that those projects are behind me, I wanted to blog about the use of one feature that made a significant difference in performance on a number of queries for this...
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