Oracle Apps DBA: Keeping E-Business Suite Alive · Module 11 · Performance: finding the actual problem
Where time actually goes
Lesson 114 of 184 · 2 min
CPU, waiting for disk, waiting for a lock, waiting for the network, or waiting for another user. FIVE VERY DIFFERENT PROBLEMS. A session is either working or waiting, and if it is waiting, WHAT it is waiting for is the diagnosis. These five have almost nothing in common except that the user says the system is slow. ON CPU MEANS IT IS ACTUALLY WORKING, AND THAT IS USUALLY THE STATEMENT'S FAULT. Too much work being done — a bad plan, a missing index, a query written to read far more than it needs. The fix is the SQL, and adding CPU buys a proportional and expensive improvement to something that should not be running at all. WAITING FOR DISK MEANS IT IS READING TOO MUCH. Often the same underlying cause as the first, seen from the other side. Faster storage helps and is treating the symptom; reading less is the…
The full lesson is part of the course
The video, the complete written lesson and the module quiz are included in Oracle Apps DBA: Keeping E-Business Suite Alive, with a certificate on completion and a fourteen-day refund window.
In this module: Module 11 · Performance: finding the actual problem
- 1Measure before you tuneFree preview
- 2"The system is slow": turning that into a question
- 3Where time actually goes
- 4AWR and ASH, used properly
- 5A baseline is what makes a report meaningful
- 6Finding the expensive SQL
- 7Execution plans, enough to act
- 8Statistics: the commonest real cause
- 9Locking and blocking
- 10When it is the application, not the database
- 11What breaks: four performance investigations that went wrong
- 12Lab briefing · Diagnose three slow systems