Currently we see a lot of issues with the Multiple Logwriter feature in Oracle Database 126.96.36.199, especially on the IBM AIX platform.
What are Multiple LGWRs?
You will see multiple LGnn (Log Writer Worker) processes on multiprocessor systems, The LGWR (Log Writer) creates worker processes (slaves) to improve the performance of writing to the redo log. LGnn (Log Writer Worker) processes are not used when there is a SYNC standby destination. Possible processes include LG00–LG99.
Here is a list of new background processes in Oracle Database 12.1:
MOS Note 1625912.1 – New Background …