set line 200;
set pagesize 2000;
select dest_id,status,error from v$archive_dest;

*** 2018-07-02 09:37:36.230
OCIServerAttach failed -1
.. Detailed OCI error val is 12154 and errmsg is 'ORA-12154: TNS:could not resolve the connect identifier specified
'
OCIServerAttach failed -1
.. Detailed OCI error val is 12154 and errmsg is 'ORA-12154: TNS:could not resolve the connect identifier specified
'
OCIServerAttach failed -1
.. Detailed OCI error val is 12154 and errmsg is 'ORA-12154: TNS:could not resolve the connect identifier specified
'
OCIServerAttach failed -1
.. Detailed OCI error val is 12154 and errmsg is 'ORA-12154: TNS:could not resolve the connect identifier specified
'
*** 2018-07-02 09:37:36.246 4329 krsh.c
Error 12154 received logging on to the standby

Cause

After adding a new standby database, a corresponding new TNS alias entry was added to the tnsnames.ora on the primary node, but neither the instance nor the archiver processes were restarted.

The ARC processes read the tnsnames.ora only once during process initialization, any updates to the tnsnames.ora after startup will not be known to the ARC process and hence the error
ORA-12154: TNS:could not resolve the connect identifier specified
is reported when the ARC processes try to resolve the (new) value for the 'service' attribute.

1. Shutdown and restart the primary database instance.

This will cause a (short) outage of the primary database and may not be feasible for this reason.

2. Use a connect descriptor for the 'service' parameter.

Instead of using a TNS alias for the service parameter (which requires a lookup of the tnsnames.ora file) one can use the connect descriptor itself.

Assume the following (new) entry in the tnsnames.ora on the primary node:

REMOTE_DEST_NEW = (DESCRIPTION = (ADDRESS = (PROTOCOL = TCP)(HOST = standbynode)(PORT = 1521)) (CONNECT_DATA = (SERVER = DEDICATED) (SERVICE_NAME = STDBY) ) )


The corresponding 'alter system' command would then be:
alter system set log_archive_dest_2 = 'service="(DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=standbynode)(PORT=1521))(CONNECT_DATA=(SERVER=DEDICATED)(SERVICE_NAME=STDBY)))"' ;


Please note that there's a length limit for the log_archive_dest_<n> parameter, so this will only work if the length of the connect string plus the length of other attributes specified does not exceed this limit.

3. Kill the ARC processes of the primary instance.

With RDBMS releases <= 9.2 it was possible to stop and restart the archiver processes by issuing 'archive log stop' followed by 'archive log start'.
However these commands are no longer valid with 10g and above, so to cause a respawn of the archiver processes they must be killed, they will be restarted immediately by the instance.

This solution requires due care to avoid accidentally killing other vital background processes.

The following script (ksh,bash) may assist in identifying the correct ARC processes that need to be killed:

ps -ef|egrep "ora_arc.*_${ORACLE_SID}"|grep -v grep |while read user pid junk
do
 echo "kill -9 $pid"
done

查詢從庫日志應用情況：
select sequence#,archived,applied from v$archived_log order by sequence#;
改變歸檔路徑：
alter system set LOG_ARCHIVE_DEST_STATE_3=defer scope=both;

alter system set LOG_ARCHIVE_DEST_3='SERVICE=dbs ASYNC VALID_FOR=(ONLINE_LOGFILES,PRIMARY_ROLE) DB_UNIQUE_NAME=dbs' scope=both;

alter system set log_archive_dest_1='location=/oracle/oradata/db/arch VALID_FOR=(ALL_LOGFILES,ALL_ROLES) DB_UNIQUE_NAME=db' scope=both;