Titlebook: Oracle SQL Tuning with Oracle SQLTXPLAIN; Stelios Charalambides Book 20131st edition Stelios Charalambides 2013

perpetual

How Skewness Can Make Your Execution Times Variable,ased optimizer. It makes a difference as to what the optimizer decides to do. It is so important that Oracle created new features such as Adaptive Cursor Sharing just to handle the consequences of skewness.

顽固

Troubleshooting Query Transformations,ate execution plans that are both easy to generate and that run fast. The optimizer uses a number of “tricks” along the way to improve the speed of execution and implements the execution plan in a way that gives the same results as your unmodified SQL. These “tricks” (or heuristics) sometimes includ

附录

Forcing Execution Plans Through Profiles,ion time pressures to get something done, any way that works is good enough. The idea is to get the business back up and running, then sit at your leisure and work out what went wrong, figure out how to stop it from happening again, and develop a plan to implement the permanent fix in a controlled m

软弱

勤劳

Dynamic Sampling and Cardinality Feedback,been told there are 2 or 3 books in the study, and that there is an index in the desk if you need it. Naturally with 2 or 3 books or even a dozen books, there’s no point in using the index in the desk, you’ll just look at the book titles one by one and quickly find all of the books with “Vienna” in

antiandrogen

conduct

Comparing Execution Plans,t plan as a guide to bring the bad execution plan into compliance. In Chapter 6 we talked about using SQL Profiles to apply a plan onto another database’s SQL, in order to have an emergency option. Suppose, however, you have more time to consider the difference and try to fix it properly, rather tha

放纵

Building Good Test Cases,spects have been eliminated and a more thorough investigation may be required. In cases like these it is useful to build a test case to allow experimentation away from the main environment. If you are investigating a problematic SQL in a test environment, normally you would try and make the environm

impale

Using XPLORE to Investigate Unexpected Plan Changes,the test case utility and how that could build an entire environment for testing SQL, system parameter, optimizer settings, objects statistics, enough of the settings in fact to make the optimizer behave as if it was on the source system. Once you achieve that state you have a superb environment to

破裂

Trace Files, TRCANLZR and Modifying SQLT behavior,ret 10046 files is outside the scope of this book. The standard guide for this is Cary Millsap’s book . (O’Reilly 2003). (This book is a little dated now, but still contains useful information on 10046 trace files.) How to more easily collect these trace files, however, and format them so they are e