Post stopped suddenly with OCIServerAttach failed with ORA-12520. There is no other message written in opo log.
This issue is caused by a combination of two factors:
1. Oracle was started up with low setting of number sessions and processes.
2. Post opens too many concurrent transactions which are exceeding the number of open sessions and processes in Oracle settings.
1. Modify SP_OPO_IDLE_LOGOUT parameter to a smaller value. So sessions logout faster.
2. Increase numberOS sessions and processes in oracle setting and bounce the database.
To confirm the issue do the following:
Query oracles parameters to verify oracles current sessions and processes setting.
Read messages of the post queue from qview. The output of oread should show there are many sque before it reaches the first commit. The number of sque plus the number of current sessions in oracle will be more than the oracles current sessions setting.