|
Problem IC64403
|
Status: Closed |
System controller EDU (DB2SYSC) held up due to contention for th e FCM dynamic update latch causes apparent performance slowdown. |
| product: |
DB2 FOR LUW / DB2FORLUW / 950 - DB2 |
| Problem description: |
Multiple logical nodes on the same machine share the same FCM
resource pools. The system controller EDU (db2sysc) on each
logical node wakes up periodically to determine if FCM
resource tuning is necessary. The system controller EDUs
contend for the FCM dynamic update latch in order to perform
the tuning. The remaining system controller EDUs and agent EDUs
can end up waiting for the latch until tuning completes and the
latch
is released. This can lead to performance slowdowns. |
| Problem Summary: |
****************************************************************
* USERS AFFECTED: *
* ALL ESE + DPF users *
****************************************************************
* PROBLEM DESCRIPTION: *
* Multiple logical nodes on the same machine share the *
* same FCM resource pools. The system controller EDU (db2sysc) *
* on each logical node wakes up periodically to determine if *
* FCM resource tuning is necessary. The system controller *
* EDUs contend for the FCM dynamic update latch in order to *
* perform the tuning. The remaining system controller EDUs and *
* agent EDUs can end up waiting for the latch until tuning *
* completes and the latch is released. This can lead to *
* performance slowdowns. *
****************************************************************
* RECOMMENDATION: *
* Upgrade to v95 fixpack 6 or higher. *
**************************************************************** |
| Local Fix: |
|
| available fix packs: |
DB2 Version 9.5 Fix Pack 6a for Linux, UNIX, and Windows
DB2 Version 9.5 Fix Pack 7 for Linux, UNIX, and Windows
DB2 Version 9.5 Fix Pack 8 for Linux, UNIX, and Windows
DB2 Version 9.5 Fix Pack 9 for Linux, UNIX, and Windows
DB2 Version 9.5 Fix Pack 10 for Linux, UNIX, and Windows
|
| Solution |
FCM self-tuning should use a best-effort approach --if a
db2sysc cannot get the latch to perform the operation, it will
retry in
the next tuning interval. The system controller EDUs should not
be held up for
a long period of time.
This issue is fixed in v95 fixpack 6. Customer should not see
performance slowdown due to db2sysc waiting behind the tuning
latch. |
| Workaround |
not known / see Local fix |
| BUG-Tracking |
forerunner : APAR is sysrouted TO one or more of the following: IC65712 IC80198
follow-up : |
| Timestamps |
Date - problem reported :
Date - problem closed :
Date - last modified :
| 06.11.2009
05.03.2010
05.03.2010 |
| Problem solved at the following versions (IBM BugInfos) |
9.5.FP6
|
| Problem solved according to the fixlist(s) of the following version(s) |
