2449423 - Certain conditions of failure where partial rollbacks of global transactions occur, could lead to object corruption in SAP IQ | SAP Knowledge Base Article

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2449423 - Certain conditions of failure where partial rollbacks of global transactions occur, could lead to object corruption in SAP IQ

Symptom

Certain conditions of failure where partial rollbacks of global transactions occur, could lead to object corruption in SAP IQ. It has been found more so in a very busy multiplex setup. In some cases the corruption is irrecoverable, meaning even select into from corrupt object into temp table will fail.

In most of the object corruption instances you will see the following :
main Bufman: Incorrect page header read; from slib/s_trycatch.cxx:2928
expected: btype=13,blk=33296,pbn=979974326,nlb=16,npb=5,uid=10481352,txn=25897138,sp=1,mn=234,upmn=234,flgs=0x80000018,iscmp=1                        
read: btype=-161,nlb=59101,npb=49075,ctr=127,cta=222,pbn=6480671059100559359,txn=18446736851143229420,sp=4294967195,ver=255,pb=255,pus=59379 iscmp=1
Expected Pad1: 200 (0xc8), Pad2: 33296 (0x8210)
Got Pad1: 255 (0xff), Pad2: 59379 (0xe7f3)
There was an s_buf::Read() error during s_bufman::Find().

The stacktrace function calls for the corruption could differ depending on where it is getting caught
In the cases where the data pages read happen to align with new page boundaries and the meta-data in the page header consistently have later larger transaction numbers. This indicates that expected pages were overwritten by space allocated to later transactions.


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Environment

SAP IQ 16.0 SP11 PL05

Product

SAP IQ 16.0

Keywords

Sybase , CR806769, CR#806769, 806769 , bufman , page corruption , stacktrace, stktrc , signal 11, abort , KBA , BC-SYB-IQ , Sybase IQ , Bug Filed

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