Index Sample Size

Posted Leave a commentPosted in Indexes, Oracle, Table stats

Recently i was asked a question, what would be the sample size percentage for indexes when tables stats are gathered with estimate percent of 5 and cascade set to true.My answer to it was 5 within a second.I had this believe that the sample size percentage for an index is same to the estimate_percent given […]

Optimizer Statistics Whitepaper

Posted Leave a commentPosted in 10gR2, 11gR2, method_opt, optimizer, Oracle

The CBO team has released two white papers on Optimizer.The first paper was released in Nov 2011, which was titled “Understanding Optimizer Statistics” and this month Apr 2012, they have released “Best Practices for Gathering Optimizer Statistics”. I would say its a must read. https://blogs.oracle.com/optimizer/entry/lies_damned_lies_and_statistics https://blogs.oracle.com/optimizer/entry/lies_damned_lies_and_statistics1 Also Timur Akhmadeev has started Poll on the METHOD_OPT […]