Previously, when we disable Vectorized ADC we would pass in a
cached tableUse in the disableVectADCRPC message for other nodes
to use to build a table accessor to disable vectorized ADC. This
can cause several issues if the table accessor's table use
causes it to perform unnecessary actions. For example, if the
table use is TableIsUsedFor_FastInsert, then the table accessor
will attempt to reserve an insert range when it does not need
to. Thus, our solution to this problem is to create a new table
use specifically for disabling Vectorized ADC that we will pass
in disableVectADCRPC. This tableUse will allow the table
accessor to bypass all of these unnecessary actions.
If you are getting an assertion related to this issue, a key
sign that you have this problem is if you see a message similar
to the one posted below dumped in the CDE_DATA flight recorder
(...CDE_SERVICES.CDE_DATA.events.fmt) inside the FODC_AppErr
folder. Specifically, what makes this message abnormal is that
we see "18" under Data4, but there is no Data5. If Data4 has
"18" and Data5 is also present, that is normal. The reason why
this issue occurs is that two threads are given the same logical
thread ID, and both will try to reserve insert ranges, leading
to an assertion.
7972 Event sequence number: 753479514 Time:
TableAccessorAllocator::TableAccessorAllocator
(3.220.935.0.126)
PID: 24296 TID: 17712109515104 EDUID: 71004
APPHDL: 0-52215
Data1 (PD_TYPE_STRING,31) String:
this / mAddressMode / mTableUse
Data2 (PD_TYPE_PTR,8) Pointer:
0x00001019b3251d10
Data3 (PD_TYPE_UINT,4) unsigned integer:
0
Data4 (PD_TYPE_UINT,4) unsigned integer:
18
Stack:
===========
-----Frame------ ------Address----- ------Function +
Offset------
0x0000101936FE7EA0 0x000010000008FE7C pthread_kill + 0x006c
( = offset 0xFE7C in /lib64/libpthread.so.0)
0x0000101936FE7ED0 0x000010000470C3AC
_Z15sqldDumpContextP9sqeBsuEduiiiiiPKcPvi + 0x112c
( = offset 0x43AC3AC in
/head/home/db2inst1/sqllib/lib64/libdb2e.so.1)
0x0000101936FE85F0 0x000010000EB7EFB0
_Z15sqlrr_dump_ffdcP8sqlrr_cbii + 0x0790
( = offset 0xE81EFB0 in
/head/home/db2inst1/sqllib/lib64/libdb2e.so.1)
0x0000101936FE87F0 0x000010001062FE60
_Z13sqlzeDumpFFDCP8sqeAgentjP5sqlcai + 0x01a0
( = offset 0x102CFE60 in
/head/home/db2inst1/sqllib/lib64/libdb2e.so.1)
0x0000101936FE88B0 0x000010001062F974
_Z12sqlzeSqlCodeP8sqeAgentjmjP5sqlcaitPc + 0x02b4
( = offset 0x102CF974 in
/head/home/db2inst1/sqllib/lib64/libdb2e.so.1)
0x0000101936FE89F0 0x000010000ECFA884 sqlrrSqlCode + 0x0184
( = offset 0xE99A884 in
/head/home/db2inst1/sqllib/lib64/libdb2e.so.1)
0x0000101936FE8C60 0x0000100004BFEE7C
_ZN7ibm_cde8services24AssertionFailedException4doneEv + 0x056c
( = offset 0x489EE7C in
/head/home/db2inst1/sqllib/lib64/libdb2e.so.1)
0x0000101936FE9140 0x0000100004BFFBC8
_ZN7ibm_cde8services24AssertionFailedException17constructAndThro
wENS0_11ComponentIDEPKcmS4_S4_RNS0_16CdeOStringStreamE + 0x0108
( = offset 0x489FBC8 in
/head/home/db2inst1/sqllib/lib64/libdb2e.so.1)
0x0000101936FE9A50 0x0000100005ACDCFC
_ZN7ibm_cde4data22InsertRangeDistributor18reserveInsertRangeEPNS
0_14CDEApplicationERNS0_13TableAccessorEPS4_m + 0x07cc
( = offset 0x576DCFC in
/head/home/db2inst1/sqllib/lib64/libdb2e.so.1)
0x0000101936FE9F90 0x000010000517255C
_ZN7ibm_cde4data14CDEApplication24findOrReserveInsertRangeERNS0_
13TableAccessorEPS2_mRb + 0x067c
( = offset 0x4E1255C in
/head/home/db2inst1/sqllib/lib64/libdb2e.so.1)
0x0000101936FEA3A0 0x0000100005E3F34C
_ZN7ibm_cde4data13TableAccessor24associateWithInsertRangeEPS1_mR
b + 0x009c
( = offset 0x5ADF34C in
/head/home/db2inst1/sqllib/lib64/libdb2e.so.1)
0x0000101936FEA420 0x0000100005E166F0
_ZN7ibm_cde4data22TableAccessorAllocator34setupSharedTableAccess
orsForInsertENS_8services18CountedPtrWithCopyINS0_13TableAccesso
rELNS2_16CountedPtrDeleteE0ELNS2_19CountedPtrThreadingE1EEES7_ +
0x00c0
( = offset 0x5AB66F0 in
/head/home/db2inst1/sqllib/lib64/libdb2e.so.1)
0x0000101936FEA4E0 0x0000100005E1656C
_ZN7ibm_cde4data22TableAccessorAllocator25allocTandemTableAccess
orsERKSbIcSt11char_traitsIcENS_8services9AllocatorIcEEES9_RKNS0_
7TableIDEm + 0x023c
( = offset 0x5AB656C in
/head/home/db2inst1/sqllib/lib64/libdb2e.so.1)
0x0000101936FEA620 0x0000100005E1579C
_ZN7ibm_cde4data22TableAccessorAllocator18allocTableAccessorERKS
bIcSt11char_traitsIcENS_8services9AllocatorIcEEES9_RKNS0_7TableI
DEm + 0x040c
( = offset 0x5AB579C in
/head/home/db2inst1/sqllib/lib64/libdb2e.so.1)
0x0000101936FEA780 0x0000100005E14794
_ZN7ibm_cde4data22TableAccessorAllocator23getTableAccessorNoStri
pERKSbIcSt11char_traitsIcENS_8services9AllocatorIcEEES9_RKNS0_7T
ableIDEm + 0x02a4
( = offset 0x5AB4794 in
/head/home/db2inst1/sqllib/lib64/libdb2e.so.1)
0x0000101936FEA940 0x0000100005D80E44
_ZN7ibm_cde4data22TableAccessorAllocator16getTableAccessorERKSbI
cSt11char_traitsIcENS_8services9AllocatorIcEEES9_RKNS0_7TableIDE
m + 0x0394
( = offset 0x5A20E44 in
/head/home/db2inst1/sqllib/lib64/libdb2e.so.1)
0x0000101936FEAAC0 0x0000100006495680
_ZN7ibm_cde4data23TableAccessorRPCHandler25getUpdatableTableAcce
ssorEv + 0x0050
( = offset 0x6135680 in
/head/home/db2inst1/sqllib/lib64/libdb2e.so.1)
0x0000101936FEAAF0 0x00001000064E2730
_ZN7ibm_cde4data17DisableVectADCRPC10processReqEv + 0x00b0
( = offset 0x6182730 in
/head/home/db2inst1/sqllib/lib64/libdb2e.so.1)
.....etc |
Disable Vectorized ADC using db2set command:
DB2_CDE_COMPRESSION_SETTINGS="ENABLE_VECT_ADC:0"
--Instance recycle needed.
--Note, this may be a workaround to try until the complete fix
is given by IBM, as enabling this has more performance impact.
Also, once tested and if this registry helps solving the issue,
then reset to original value and contact IBM support with the
test outcome.
--This registry is not a permanent fix ,just a temporary
workaround to test if issue resolves.
reset the registry:
DB2_CDE_COMPRESSION_SETTINGS=
--Instance recycle needed. |
