kill掉相关进程或重启oracle, sqlplus "/as sysdba"
SQL> show parameter processes;
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
aq_tm_processes integer 1
db_writer_processes integer 1
job_queue_processes integer 10
log_archive_max_processes integer 2
processes integer 500
SQL> alter system set processes=500 scope = spfile;
System altered.
SQL> commit;
Commit complete.
SQL> shutdown immediate;
SQL> startup;
SQL> show parameter processes;
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
aq_tm_processes integer 1
db_writer_processes integer 1
job_queue_processes integer 10
log_archive_max_processes integer 2
processes integer 500