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Problem IC84305
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Status: Closed |
PERFORMING REMOTE APPLICATION SNAPSHOTS CONCURRENTLY MAY CAUSE THE INSTANCE HUNG |
| product: |
DB2 FOR LUW / DB2FORLUW / A10 - DB2 |
| Problem description: |
In a federated DB2 database server environment, if multiple
users or clients are collecting remote application snapshots
concurrently, it may sometimes cause a dead latch in the DB2
server which may effectively lead to the instance hanging.
When the instance is hung, the stacks and the latches of the
two agents may look like below:
1) the agent 1 is holding the master application latch -
SQLO_LT_sqeApplication__masterAppLatch, but waiting on the
remote latch - SQLO_LT_sqlmon_dbcb__xlatch_remote_list.
thread_waitlock
sqloXlatchConflict
sqm_snap_appl_remote
sqlmonssagnt
sqlmonssbackend
sqlesrvr
sqleMappingFnServer
sqlerKnownProcedure
sqlerCallDL
2) While the agent 2 is holding the remote latch -
SQLO_LT_sqlmon_dbcb__xlatch_remote_list, but is waiting on the
master application latch -
SQLO_LT_sqeApplication__masterAppLatch.
thread_waitlock
sqloXlatchConflict
estim_appl_remote_snap_sz
sqlmonszagnt
sqlmonszbackend
sqlesrvr
sqleMappingFnServer
sqlerKnownProcedure
sqlerCallDL
Thus there is a dead latch situation between these two agents.
As these agents may also be holding other latches, such as the
database latch, the application service latch, etc., this may
eventually cause the instance to appears as hung, that is,
terminating an existing connection or new database connections
may get hung on these latches. The only way to get out of this
hang is to recycle the db2 instance. |
| Problem Summary: |
****************************************************************
* USERS AFFECTED: *
* Users in a federated DB2 database server environment where *
* multiple users or clients are collecting remote application *
* snapshots concurrently. *
****************************************************************
* PROBLEM DESCRIPTION: *
* See Error Description *
****************************************************************
* RECOMMENDATION: *
* Upgrade to DB2 Version 10.1 Fix Pack 1 or newer *
**************************************************************** |
| Local Fix: |
-Recycle the instance to resolve the hang and avoid collection
of remote application snapshots as much as possible. Please note
that some tools such as db2top may collect such snapshots
undercover, avoid to run these tools if possible. |
| available fix packs: |
DB2 Version 10.1 Fix Pack 1 for Linux, UNIX, and Windows
DB2 Version 10.1 Fix Pack 2 for Linux, UNIX, and Windows
DB2 Version 10.1 Fix Pack 3 for Linux, UNIX, and Windows
DB2 Version 10.1 Fix Pack 4 for Linux, UNIX, and Windows
DB2 Version 10.1 Fix Pack 3a for Linux, UNIX, and Windows
DB2 Version 10.1 Fix Pack 6 for Linux, UNIX, and Windows
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| Solution |
Problem was first fixed in Version 10.1 Fix Pack 1 |
| Workaround |
See above Local Fix |
| Timestamps |
Date - problem reported :
Date - problem closed :
Date - last modified :
| 13.06.2012
22.11.2012
22.11.2012 |
| Problem solved at the following versions (IBM BugInfos) |
|
| Problem solved according to the fixlist(s) of the following version(s) |
| 10.1.0.1
|
 |
| 10.5.0.1
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