What is the function of SMON?- The SMON background process performs all system monitoring functions on the oracle database.
- Each time oracle is re-started, SMON performs a warm start and makes sure that the transactions that were left incomplete at the last shut down are recovered.
- SMON performs periodic cleanup of temporary segments that are no longer needed.
- The system monitor process (SMON) performs recovery, if necessary, at instance startup.
- SMON is also responsible for cleaning up temporary segments that are no longer in use and for coalescing contiguous free extents within dictionary managed tablespaces.
- If any terminated transactions were skipped during instance recovery because of file-read or offline errors, SMON recovers them when the tablespace or file is brought back online.
- SMON checks regularly to see whether it is needed.
- Other processes can call SMON if they detect a need for it.
- With Real Application Clusters, the SMON process of one instance can perform instance recovery for a failed CPU or instance.