If the rebalancer moves tablespace containers from one storage
group to another and crashes before committing the rebalance
changes, then during the subsequent crash recovery the
rebalancer will not be able to find the path to the old
tablespace containers. This will result in a database panic
(abend), i.e. crash recovery will be unable to complete,
therefore it will not be possible to connect to the database.
This issue is timing sensitive - the initial rebalance must fail
at a very precise point - which is difficult to hit in a real
life scenario. The following data was gathered on a system where
this problem was simulated:
db2diag.log
===========
2010-11-10-17.02.46.808455-480 I3768037E683 LEVEL:
Severe
PID : 4675 TID : 47865472739648 KTID : 5383
PROC : db2sysc
INSTANCE: db2inst1 NODE : 000
EDUID : 35 EDUNAME: db2rebal (SAMPLE)
FUNCTION: DB2 UDB, buffer pool services, sqlbDMSOpenContainer,
probe:20
MESSAGE : ZRC=0x870F0011=-2029060079=SQLO_PATH "an invalid path"
DIA8514C An invalid file path, "", was specified.
DATA #1 : String, 66 bytes
/u/db2inst1/db2inst1/SAMPLE/NODE0000/T0000007/C0000000.LRG
DATA #2 : Object control block, PD_TYPE_SQLB_OBJECT, 12 bytes
Obj: {pool:7;obj:0;type:0} Parent={0;0}
DATA #3 : unsigned integer, 4 bytes
0
2010-11-10-17.02.46.819668-480 I3768721E455 LEVEL:
Severe
PID : 4675 TID : 47865472739648 KTID : 5383
PROC : db2sysc
INSTANCE: db2inst1 NODE : 000
EDUID : 35 EDUNAME: db2rebal (SAMPLE)
FUNCTION: DB2 UDB, buffer pool services,
SqlbFhdlTbl::getFileHandle, probe:10
RETCODE : ZRC=0x870F0011=-2029060079=SQLO_PATH "an invalid path"
DIA8514C An invalid file path, "", was specified.
2010-11-10-17.02.46.821831-480 I3769177E449 LEVEL:
Error
PID : 4675 TID : 47865472739648 KTID : 5383
PROC : db2sysc
INSTANCE: db2inst1 NODE : 000
EDUID : 35 EDUNAME: db2rebal (SAMPLE)
FUNCTION: DB2 UDB, buffer pool services, sqlbPostRebalanceWork,
probe:40
MESSAGE : ZRC=0x870F0011=-2029060079=SQLO_PATH "an invalid path"
DIA8514C An invalid file path, "", was specified.
2010-11-10-17.02.46.823768-480 I3769627E443 LEVEL:
Severe
PID : 4675 TID : 47865472739648 KTID : 5383
PROC : db2sysc
INSTANCE: db2inst1 NODE : 000
EDUID : 35 EDUNAME: db2rebal (SAMPLE)
FUNCTION: DB2 UDB, buffer pool services, sqlb_rebalance,
probe:50
MESSAGE : ZRC=0x870F0011=-2029060079=SQLO_PATH "an invalid path"
DIA8514C An invalid file path, "", was specified.
2010-11-10-17.02.46.827628-480 I3770566E645 LEVEL:
Severe
PID : 4675 TID : 47865472739648 KTID : 5383
PROC : db2sysc
INSTANCE: db2inst1 NODE : 000
EDUID : 35 EDUNAME: db2rebal (SAMPLE)
FUNCTION: DB2 UDB, buffer pool services, sqlb_rebalance,
probe:50
DATA #1 : String, 299 bytes
Current Map: Map Error
Map entry size: 80
Map entries: 1
Map size: 1
Set Range Off MaxExtent MaxPage StartStr EndStr Adj
Conts
---- ----- --- --------- ------- -------- ------ ---
-----
[ 0] [ 0] 0 27 895 0 6 0 4
(1, 2, 3, 4)
2010-11-10-17.02.46.829504-480 I3771212E377 LEVEL:
Severe
PID : 4675 TID : 47865472739648 KTID : 5383
PROC : db2sysc
INSTANCE: db2inst1 NODE : 000
EDUID : 35 EDUNAME: db2rebal (SAMPLE)
FUNCTION: DB2 UDB, buffer pool services, sqlb_rebalance,
probe:50
DATA #1 : String, 31 bytes
sqlbPrintMap(): New map is NULL
2010-11-10-17.02.46.831488-480 E3771590E843 LEVEL:
Critical
PID : 4675 TID : 47865472739648 KTID : 5383
PROC : db2sysc
INSTANCE: db2inst1 NODE : 000
EDUID : 35 EDUNAME: db2rebal (SAMPLE)
FUNCTION: DB2 UDB, RAS/PD component, pdStartFODC, probe:10
MESSAGE : ADM14001C An unexpected and critical error has
occurred: "Panic".
The instance may have been shutdown as a result.
"Automatic" FODC
(First Occurrence Data Capture) has been invoked and
diagnostic
information has been recorded in directory
"/u/db2inst1/sqllib/db2dump/FODC_Panic_2010-11-10-17.02.46.83139
2/".
Please look in this directory for detailed evidence
about what
happened and contact IBM support if necessary to
diagnose the
problem. |
