1、rman备份时会消耗这么多临时表空间
参考MOS：
RMAN-08132: Warning: Cannot Update Recovery Area ORA-01652: unable to extend temp segment by 64 in tablespace TEMP (Doc ID 2658437.1)
Known RMAN Performance Problems (Doc ID 247611.1)
处理办法：备份时，会话级别将optimizer_mode由ALL_ROWS改成RULE
RMAN> sql "alter session set optimizer_mode=RULE";
2、配置向下兼容模式- oracle用户执行
处理办法：
orcl:/home/oracle@db> echo 'SQLNET.ALLOWED_LOGON_VERSION_SERVER=8' >> $ORACLE_HOME/network/admin/sqlnet.ora
orcl:/home/oracle@db> echo 'SQLNET.ALLOWED_LOGON_VERSION_CLIENT=8' >> $ORACLE_HOME/network/admin/sqlnet.ora
3、配置密码复杂度
@?/rdbms/admin/utlpwdmg.sql
PASSWORD_VERIFY_FUNCTION 19c使用的是 ORA12C_VERIFY_FUNCTION
取消Oracle密码复杂度检查：
SQL> alter profile default limit password_verify_function null;
prompt 查看所有的PROFILE
set pagesize 199 linesize 199;
col PROFILE for a20;
col RESOURCE_NAME for a30;
col LIMIT for a30;
select * from dba_profiles where PROFILE='DEFAULT' order by PROFILE;