|
Problem IC74916
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Status: Closed |
PROCESSING DELAY OCCURING EVERY 2 HOURS WHEN HEALTH MONITOR IS ENABLED |
| product: |
DB2 FOR LUW / DB2FORLUW / 950 - DB2 |
| Problem description: |
Systems with Health Monitor enabled (HEALTH_MON = ON) may
experience delays in transaction processing every 2 hours. This
is due to health monitor's "backup evaluation" process, which
needs to query the history file.
The history file processing is inefficient, resulting in holding
a lock on the history file for a long time if the file is large.
If the log writer needs to write to a new log file during this
period, it will wait for the backup evaluation to complete, as
this event must be added into the history file, and the log
writer must acquire the history file lock to do so. Commit and
rollback activity, and possibly other database operations, will
be blocked until the log writer can add the history file entry
and continue normal processing.
The two-hour interval between delays is a near-certain match for
this problem. In addition, a call stack of the db2 log writer
process (db2loggw) will be similar to the following:
sqloNLCKLock
sqluhLock
sqluhAllocateHandleVerifyHistoryFiles
sqluhOpen
sqluhBeginBatch
sqluhInsertSingle
sqlpAddNewLogToHistFile
sqlpgOpenNextExt |
| Problem Summary: |
****************************************************************
* USERS AFFECTED: *
* Systems with Health Monitor enabled (HEALTH_MON = ON) *
****************************************************************
* PROBLEM DESCRIPTION: *
* See Error Description *
****************************************************************
* RECOMMENDATION: *
* Upgrade to Version 9.5 Fix Pack 8 or see Circumvention *
**************************************************************** |
| Local Fix: |
Various workarounds exist:
1. Disable Health Monitor altogether:
db2 update dbm cfg using health_mon off ( dynamic if
issued over an instance attachment )
2 Disable the "backup required" health indicator:
db2 update alert configuration for database on <database>
using db.db_backup_req set thresholdschecked no
3. Prune history log |
| available fix packs: |
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 |
Problem first fixed in DB2 Version 9.5 Fix Pack 8 |
| Workaround |
not known / see Local fix |
| BUG-Tracking |
forerunner : APAR is sysrouted TO one or more of the following: IC74970
follow-up : |
| Timestamps |
Date - problem reported :
Date - problem closed :
Date - last modified :
| 08.03.2011
11.08.2011
11.05.2012 |
| Problem solved at the following versions (IBM BugInfos) |
9.5.FP8
|
| Problem solved according to the fixlist(s) of the following version(s) |
| 9.5.0.8
|
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