DB2 UDB for z/OS Version 8 Performance Topics - IBM Redbooks

Another use is during back out of a long running process that issues a ROLLBACK. DB2
Archive Log Accelerator compresses the archive log as an effort to reduce the times to
recover from such situations.
Preliminary measurements are listed in Table 10-1.
Table 10-1 RECOVER and Archive Log Accelerator
RECOVER from
active log has ET of
335 sec.
Stripes
These measurements are for RECOVER with PTF UQ90143 for PQ88896 applied.
RECOVER with ALA, striping and compression, shows an elapsed time improvement of
almost 30%. Increasing the number of stripes did not improve elapsed time.
For more information about this DB2 tool, see:
http://www.ibm.com/software/data/db2imstools/
DB2 Archive Log Accelerator V2.1 fully exploits DB2 V8.
10.6 DB2 Query Monitor
RECOVER from
archive log
CPU/ET (sec.)
Monitoring and tuning the SQL activity in a DB2 subsystem is important especially when
problems occur that affect the response times. You may need to identify problematic SQL
statements and focus on improving the response times of important transactions. DB2 Query
Monitor allows you to view current and historical query activity within your DB2 subsystems
and make important decisions affecting its performance.
For more information about this DB2 tool, see
http://www.ibm.com/software/data/db2imstools/
Here is a list of features of Query Monitor V2.1:
► Data collection and activity viewing features
► SQL statement resource consumption
► Object access statistics with granularity down to the object level
► Current active statements in DB2
► Pinpoint SQL from many different views:
– Plan
– Program
– User
– SQL statement
► Ability to exclude workloads or specific SQLCODEs
► Set exception limits and thresholds
► Define alert notification thresholds
368 DB2 UDB for z/OS Version 8 Performance Topics
With ALA
CPU/ET (sec.)
With ALA and
compression
CPU/ET (sec.)
1 183/460 177/444 176/323
2 N/A 176/439 176/330
4 N/A 176/435 176/324
non-ext ds 177/543 N/A N/A