Performance Tuning for Content Manager

Chapter 8. Tuning DB2 for Content Manager 181

8.3 Regular routine maintenance

In this section, we describe what you need to do as routine maintenance to

ensure that your system is performing at the optimal level. The maintenance

tasks include:

 Keeping up with the latest software fix packs

 Monitoring system performance using the DB2 snapshot

 Keeping database statistics and execution plans up to date by running

runstats and rebind commands

 Reorganizing tables as necessary

 Pruning log file regularly

 Pruning diagnostics file

 Cleaning up the event log

8.3.1 Keeping up with the latest software fix packs

Software bugs are found and software enhancements are continually being

developed. DB2 is no exception. It is extremely important to keep your software up

to the latest fix pack level so that you get the benefit of these software changes.

When calls to external support are placed, one of the first things they ask is

whether your software is at the latest fix pack level. If not, they typically ask you to

update to the latest version of the software before they continue to troubleshoot

your problem to avoid trying to solve a problem that has already been solved.

Check for new fix packs at least quarterly and whenever you see a recurring

problem that other tuning suggestions cannot fix.

Fix packs for DB2 can be found at:

http://www.ibm.com/software/data/db2/udb/support/

Always read the README.TXT file before installing the fix pack to be sure that all

prerequisites are known.

8.3.2 Monitoring system performance using DB2 snapshot

System monitoring helps you understand what is happening to the system and

what kind of action you might need to take. Monitor your system on a regular

basis to ensure that it is running healthy, and to profile system usage and

performance. To do this, we recommend using the DB2 monitoring tool snapshot.

Chapter 11, “Performance monitoring, analysis, and tracing” on page 281 goes

into great detail about the use of snapshot and other monitoring tools, and the

182 Performance Tuning for Content Manager

content of this section is derived from the way a particular client monitors their

system.

How to take a snapshot

1. DB2 monitors must be set on before they can collect data. It is not necessary

to turn on all of the monitors for regular maintenance. At a minimum, have the

DFT_MON_BUFPOOL, DFT_MON_LOCK, and DFT_MON_SORT turned on.

The other switches provide a great deal of data and could be turned on to

investigate a specific problem. The switches can be turned on as follows:

a. Click Programs → IBM DB2 → General Administration Tools →

Control Center.

b. Change the following database instance parameters state to on:

DFT_MON_BUFPOOL

DFT_MON_LOCK

DFT_MON_SORT

DFT_MON_STMT

DFT_MON_TABLE

DFT_MON_TIMESTAMP

DFT_MON_UOW

HEALTH_MON

You can also turn on all monitoring switches through a DB2 command line:

update monitor switches using BUFFERPOOL on, LOCK on, SORT on,

STATEMENT on, TIMESTAMP on, TABLE on, UOW on

The database monitor switches must be turned on for sufficient time to allow

DB2 to collect meaningful data.

2. When you start database monitors, you also have to increase the database

manager monitor heap size (MON_HEAP_SZ) to allow enough memory

allocation to get the monitoring results:

a. Click Programs → IBM DB2 → General Administration Tools →

Control Center.

b. Change the database instance parameter MON_HEAP_SZ to at least

2048.

3. Run snapshot from DB2 command window:

a. Click Start → Run.

b. Type db2cmd.

c. Type the following command:

db2 get snapshot for all databases > fname.txt

• fname is the name of the file the monitoring results will be saved in.