dg配置了lgwr sync affirm不能实时同步。

dg主备都配置了lgwr sync affirm。主库startup，备库alter database open read only;然后alter database recover managed standby database disconnect from session; 发现进行数据增删改后，发现无法实现数据的实时同步，必须通过alter system switch logfile后，备库才能同步主库的数据。
要实现实时同步必须启用alter database recover managed standby database using current logfile disconnect from session;主库配置：
*.log_archive_config='dg_config=(pri,std)'
*.log_archive_dest_1='location=/u01/app/arch/ims valid_for=(all_logfiles,all_roles) db_unique_name=pri'
*.log_archive_dest_2='service=std lgwr sync affirm valid_for=(online_logfiles,primary_role) db_unique_name=std'
*.log_archive_dest_state_1='enable'
*.log_archive_dest_state_2='enable'
*.log_archive_max_processes=4
*.log_file_name_convert='/u01/app/oracle/oradata/ims','/u01/app/oracle/oradata/ims'
*.memory_target=1606418432
*.open_cursors=300
*.processes=150
*.remote_login_passwordfile='EXCLUSIVE'
*.standby_file_management='auto'
*.undo_tablespace='UNDOTBS1'备库配置
*.fal_client='std'
*.fal_server='pri'
*.log_archive_config='dg_config=(pri,std)'
*.log_archive_dest_1='location=/u01/app/arch/ims valid_for=(all_logfiles,all_roles) db_unique_name=std'
*.log_archive_dest_2='service=pri lgwr sync affirm valid_for=(online_logfiles,primary_role) db_unique_name=pri'
*.log_archive_dest_state_1='enable'
*.log_archive_dest_state_2='enable'
*.log_archive_max_processes=4
*.log_file_name_convert='/u01/app/oracle/oradata/ims','/u01/app/oracle/oradata/ims'
*.memory_target=1606418432
*.open_cursors=300
*.processes=1500
*.remote_login_passwordfile='EXCLUSIVE'
*.sessions=1655
*.standby_file_management='auto'
*.undo_tablespace='UNDOTBS1'