Hardcover: pages 1st edition June 15, Sybex The perfect way to prepare for the Oracle9i Performance Tuning exam! Provides indepth coverage of official exam objectives and hundreds of challenging review questions. CD-ROM included. Loaded with hundreds of practice questions, it lets you test yourself chapter by chapter or according to objective areas. Also included is a complete electronic version of the book.
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Define the problem clearly and then formulate a tuning goal. Second Examine the host system and gather Oracle statistics. Fifth Identify the changes to be made and then implement those changes. Sixth Determine whether the objectives identified in step one have been met. If they have, stop tuning. If not, repeat steps five and six until the tuning goal is met. Interestingly, the emphasis on identifying which step an action falls under went away with Oracle9i, and recitation of the principles is not a testable item.
When it comes to instance tuning, the steps are even further reduced in Oracle10g. The steps have been expanded, but overall, remain the same. Perform the following initial standard checks: a. Get candid feedback from users.
This process is key in future capacity planning. Get a full set of operating system, database, and application statistics from the system when the performance is both good and bad. If these are not available, then get whatever is available. Missing statistics are analogous to missing evidence at a crime scene: They make detectives work harder and it is more time-consuming. Sanity-check the operating systems of all machines involved with user performance.
By sanity-checking the operating system, you look for hardware or operating system resources that are fully utilized. List any over-used resources as symptoms for analysis later.
In addition, check that all hardware shows no errors or diagnostics. Check for the top ten most common mistakes with Oracle, and determine if any of these are likely to be the problem. List these as symptoms for later analysis. These are included because they represent the most likely problems. ADDM automatically detects and reports nine of these top ten issues. Build a conceptual model of what is happening on the system using the symptoms as clues to understand what caused the performance problems.
Propose a series of remedy actions and the anticipated behavior to the system, then apply them in the order that can benefit the application the most.
ADDM produces recommendations each with an expected benefit. A golden rule in performance work is that you only change one thing at a time and then measure the differences. Unfortunately, system downtime requirements might prohibit such a rigorous investigation method. If multiple changes are applied at the same time, then try to ensure that they are isolated so that the effects of each change can be independently validated.
Otherwise, look for more bottlenecks, and continue refining the conceptual model until your understanding of the application becomes more accurate. Repeat the last three steps until performance goals are met or become impossible due to other constraints. The performance tuning guide for Oracle10g Release 2 The Change is Part of the Problem The change from a top-down structured approach to a principle-based "make it stop hurting" one is part of the problem.
Gathering statistics is obviously important because how else do you know if you have improved or worsened the problem? Still, to some degree with either approach, you are left with the original two questions: what do I look for, and how do I make it better? If the structured approach left you scratching your head, the principled approach only adds to the confusion.
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BIJU THOMAS ORACLE 11G PDF