|
Problem IC81011
|
Status: Closed |
Hang on tranEntry latch in sqlpm_write_appl_locks during lock snapshot |
| product: |
DB2 FOR LUW / DB2FORLUW / 970 - DB2 |
| Problem description: |
In a Federated environment that utilizes two-phase commits, the
instance can hang with a LOCK snapshot waiting on a tranEntry
latch. The lock snapshot's callstack looks like this:
sqlpm_write_appl_locks
sqm_snap_appl_locks
sqm_snap_db_locks
sqlmonssagnt
sqlmonssbackend
sqlesrvr
The lock snapshot is waiting for the tranEntry latch and holding
the dblatch, m_appServLatch and masterAppLatch.
At the same time a federated server has been defined to use
two-phase commit and a federated agent is attempting to
establish an XA transaction by calling sqlqg_FMP_FedStart. The
agent's stack looks like this:
msgrcv
sqlorqueInternal
sqlorque2
sqloTQMRequestMLN
sqlccipcconnr
sqlccconnr
sqljcCommConnect
sqljcCmnMgrInit
sqljrCreateTransport
sqljrAssociateTransport
sqljrInternalConnect
sqljrFindBestAddressAndConnect
sqljrDrdaArAuthenticate
sqlexAppAuthenticate
sqljrDrdaArConnect
sqleUCdrdaARinit
sqleUCappConnect
sqlxaConnect
DRDA_Connection::xa_open
FencedServer::connect
FencedServer::connect_current_user
sqlqgConnect
sqlqg_FMP_FedStart <-------------------
sqlqgRouter
sqlqg_fedstp_hook
sqlqgDyload
sqlriFedInvokerTrusted
sqlriFedInvokeInvoker
sqlqg_Call_FMP_Thread
sqlqgFedStart
sqlqgOpen
sqlri_djx_rta
sqlriNljnPiped
sqlriSectInvoke
sqlrr_process_execute_request
sqlrr_execute
sqljs_ddm_excsqlstt
sqljsParseRdbAccessed
sqljsParse
sqljsSqlam
:
The Federated agent is holding the tranEntry latch when it calls
sqlqgConnect to establish the XA connection and is waiting for
an agent to be provided by the IPC connection manager.
The IPC connection manager is hung waiting for the
m_appServerLatch being held by the snapshot agent.
SQLO_SLATCH_CAS::getConflictComplex
SQLO_SLATCH_CAS::getConflict
sqlo_latch
sqeAppServices::CreateAppl
sqeAgentServices::RequestAgent
sqlccipcconnmgr_child
sqloEDUEntry |
| Problem Summary: |
****************************************************************
* USERS AFFECTED: *
* Anybody using federated transaction two phase commit *
* transaction and LOCK snapshots *
****************************************************************
* PROBLEM DESCRIPTION: *
* See Error Description *
****************************************************************
* RECOMMENDATION: *
* Upgrade to Version 9.7 Fix Pack 6 *
**************************************************************** |
| Local Fix: |
This hang can be avoided if the federated transaction does not
require two phase commit. Two phase commit can be disabled as
follows:
alter server <server name> options (set DB2_TWO_PHASE_COMMIT
'N') |
| available fix packs: |
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 |
Problem was first fixed in Version 9.7 Fix Pack 6 |
| Workaround |
not known / see Local fix |
| BUG-Tracking |
forerunner : APAR is sysrouted TO one or more of the following: IC83256 IC96023
follow-up : |
| Timestamps |
Date - problem reported :
Date - problem closed :
Date - last modified :
| 25.01.2012
09.05.2012
09.05.2012 |
| Problem solved at the following versions (IBM BugInfos) |
9.7.FP6
|
| Problem solved according to the fixlist(s) of the following version(s) |
| 9.7.0.6
|
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