|
Problem IC68267
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Status: Closed |
Control dynamic downward adjustment of FCM resources |
| product: |
DB2 FOR LUW / DB2FORLUW / 970 - DB2 |
| Problem description: |
Customers with large DPF environments like are experiencing
significant performance issues and
apparent hangs due to contention when FCM resources are tuned
automatically. The system
controller thread (db2sysc) will adjust FCM resources downward
after 30 minutes or more of low
workload. During relatively quiet times, the resources can get
adjusted down to very low values.
This causes problems on systems with large workload bursts. When
the workload increases dramatically,
the FCM resources need to be adjusted upwards quickly and this
is when performance issues due to latch
contention in the dynamic adjustment code occurs. This problem
gets worse on large DPF
instances with many logical partitions configured. |
| Problem Summary: |
Control dynamic downward adjustment of FCM resources |
| Local Fix: |
Large DPF customers can set FCM resources to large fixed values.
However, the downside is that this may cause node failures in
cases when db2fcmr/db2fcms EDUs run out of FCM buffers/channels. |
| available fix packs: |
DB2 Version 9.7 Fix Pack 3 for Linux, UNIX, and Windows
DB2 Version 9.7 Fix Pack 3a for Linux, UNIX, and Windows
DB2 Version 9.7 Fix Pack 4 for Linux, UNIX, and Windows
DB2 Version 9.7 Fix Pack 5 for Linux, UNIX, and Windows
DB2 Version 9.7 Fix Pack 6 for Linux, UNIX, and Windows
DB2 Version 9.7 Fix Pack 7 for Linux, UNIX, and Windows
DB2 Version 9.7 Fix Pack 8 for Linux, UNIX, and Windows
DB2 Version 9.7 Fix Pack 9 for Linux, UNIX, and Windows
DB2 Version 9.7 Fix Pack 9a for Linux, UNIX, and Windows
DB2 Version 9.7 Fix Pack 10 for Linux, UNIX, and Windows
|
| Solution |
Customers with large DPF environments like are experiencing
significant performance issues and
apparent hangs due to contention when FCM resources are tuned
automatically. The system
controller thread (db2sysc) will adjust FCM resources downward
after 30 minutes or more of low
workload. During relatively quiet times, the resources can get
adjusted down to very low values.
This causes problems on systems with large workload bursts. When
the workload increases dramatically,
the FCM resources need to be adjusted upwards quickly and this
is when performance issues due to latch
contention in the dynamic adjustment code occurs. This problem
gets worse on large DPF
instances with many logical partitions configured. |
| Workaround |
Upgrade to DB2 V9.7 FP3 |
| Timestamps |
Date - problem reported :
Date - problem closed :
Date - last modified :
| 01.05.2010
01.11.2011
01.11.2011 |
| Problem solved at the following versions (IBM BugInfos) |
|
| Problem solved according to the fixlist(s) of the following version(s) |
| 9.7.0.3
|
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| 9.7.0.3
|
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