The symptoms include issues such as the ‘ALTER DATABASE OPEN’ process not completing as logged in the alert log file. DIA0 (Hang Manager reports) sessions are also blocked while waiting for ‘gc freelist.’ The hang manager reports instances waiting for ‘cursor: pin S wait on X’ and ‘gc freelist’, which can lead to extended waiting times and potentially block other sessions.
Diagnosis by MMAN and Development
MMAN (Memory Manager) indicates an ORA-4031 error related to the shared pool, potentially caused by the bug identified as BUG 31459369. This bug leads to multiple incidents of ORA-00600 [15709], [29] during parallel execution. Development has confirmed that SGA_TARGET usage can result in an imbalance in the number of Lock Elements (LE) assigned to LMS processes on NUMA machines, along with setting a minimum size for the buffer cache due to this bug.
Workaround Suggested
To address the issues caused by the bug, the recommended workaround is to establish a minimum size for the database buffer cache and shared pool. By setting these minimum sizes, the workaround aims to mitigate the effects of the bug identified as BUG 31459369, which triggers incidents of ORA-00600 [15709], [29] with parallel execution.
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