I recently got escalation to investigate a SQL instance that
was unexpectedly shutdown due to access violation, no other error or message was
logged in Application/System/SQL error log except a memory dump.
Exception
Address = 00000000776CE660 Module(ntdll+000000000004E660)
Exception
Code = c0000005
EXCEPTION_ACCESS_VIOLATION
Access
Violation occurred reading address 0000000000000000
So I decided
to review the dump file using windbg and public symbols. Stack shown me the very last function was
OraOLEDBButl11 which is Oracle driver for linked server so it was clear that
distributed query is culprit here and right after OS started to release the
heap memory and exception dispatched which is very strange behaviour, while
searching for OraOLEDBButl11 I found a reference that gave me more info about
Oracle driver related bug, for more info refer below reference.
Reference:
https://support.microsoft.com/en-us/help/2295405/sql-server-service-crashes-when-you-run-an-oracle-linked-server-query
