IDUG DB2 Tech Conference EMEA 2011
Clarion Congress Hotel, Prague, Czech Republic
14 - 18 November, 2011

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Understanding and Tuning Page Cleaning in DB2

Session Number: 1892
Track: DB2 9.7 for LUW (C)
Session Type: Podium Presentation
Primary Presenter: Kelly Schlamb [Ibm Canada Ltd.]
Time: Nov 17, 2011 (11:15 AM - 12:15 PM)
Room: Aquarius

Speaker Bio: Kelly Schlamb has been a part of the DB2 for LUW team in the IBM Toronto Lab for 17 years, spending the majority of his career in the DB2 Kernel development group. Kelly was a long time member of the buffer pool services & storage management team, working on various new features, including leading the team that implemented Automatic Storage. The last 5 years in development were spent as the technical lead and manager of the DB2 pureScale Recovery team, responsible for designing and implementing logging, backup/restore, crash recovery, rollforward, and transaction management in the DB2 pureScale environment. Kelly has recently joined the Worldwide Information Management Technical Sales organization where he is now helping to spread the word about DB2 and pureScale
Audience experience level: Beginner
Presentation Category: Data Management
Presentation Platform: Select a Value
Audiences this presentation will apply to: Database Administrators, New Users
Technical areas this presentation will apply to: Database Performance (DB2 for LUW)
Objective 1: Understand synchronous and asynchronous page cleaning in DB2.
Objective 2: Learn how to interpret specific counters in the DB2 snapshot monitor to assess the efficiency of page cleaning in your database.
Objective 3: Learn how several DB2 configuration parameters affect page cleaning behavior.
Objective 4: Learn how to avoid synchronous page writes and how to tune for efficient page cleaning.
Objective 5: Understand how page cleaning is related to the size of log files and the time required for database recovery, and how to choose proper trade-offs.

Abstract:  Transactions that insert, update, or delete rows in a table modify pages in the DB2 buffer pool and leave them behind as "dirty pages". Eventually, DB2 needs to write those dirty pages to their respective table space. This process is known as page cleaning and can have a critical impact on write intensive applications. Insufficient as well as overaggressive page cleaning can degrade performance. There are various conditions that can trigger DB2 to write dirty pages to disk asynchronously. Likewise, a variety of tuning knobs exist to influence when these conditions are met and page cleaning kicks in. This presentation provides an introduction to DB2's page cleaning mechanism and explains the effects of the relevant configuration parameters. You will learn how to monitor DB2's page cleaning behavior, how to detect inefficient page cleaning, and how to take corrective action that improves insert, update, and delete performance.

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