Missing Log_archive_config in Oracle can cause archive paths to be disabled

A major feature of the 10g data Guard is the introduction of the Log_archive_config parameter, which may cause the archive path to be disabled if this parameter is missing.

See other people set up data guard encountered this problem, then feel more interesting, so deliberately reproduce.

The current is a configured data GUARD, in order to simulate errors, first set this parameter to null:

Sql> alter system set log_archive_config = ';

System altered.

sql> alter system switch logfile;

System altered.

Sql> Show Parameter Archive_dest_2

NAME TYPE VALUE

------------------------------------ ----------- ------------------------------

Log_archive_dest_2 string Service=standby lgwr SYNC VALI

D_for= (online_logfiles,primary

_role) Db_unique_name=standby

Sql> alter system set log_archive_dest_2 = ' Service=standby ARCH ASYNC valid_for= (online_logfiles,primary_role) DB_ Unique_name=standby ';

System altered.

sql> alter system switch logfile;

System altered.

After the log switch, there is no error in the alert file, and the switch log is executed again after the log_archive_dest_2 parameter is reset, and the expected error is still not visible in the alert file.

The reason why the problem cannot be reproduced may be that the Log_archive_config parameter has already been set in the system, and although it is now empty, the entry into force of this parameter may persist and try to restart the database:

sql> shutdown Immediate

Database closed.

Database dismounted.

ORACLE instance shut down.

Sql> Startup

ORACLE instance started.

Total System Global Area 2147483648 bytes

Fixed Size 2074112 bytes

Variable Size 486541824 bytes

Database buffers 1644167168 bytes

Redo buffers 14700544 bytes

Database mounted.

Database opened.

sql> alter system switch logfile;

System altered.

Sql> alter system set log_archive_dest_2 = ' Service=standby lgwr ASYNC valid_for= (online_logfiles,primary_role) DB_ Unique_name=standby ';

System altered.

sql> alter system switch logfile;

System altered.

This is the expected error already seen from the alert file:

Thu Dec 23 21:42:48 2010

Completed:alter DATABASE OPEN

Thu Dec 23 21:42:51 2010

Thread 1 advanced to log sequence 11

Current log# 2 seq# mem# 0:/data/oradata/primary/redo02.log

Thu Dec 23 21:42:51 2010

Errors in FILE/OPT/ORA10G/ADMIN/PRIMARY/BDUMP/PRIMARY_ARC1_18406.TRC:

Ora-16057:dgid from server not in Data Guard configuration

Thu Dec 23 21:42:51 2010

Fal[server, ARC1]: Error 16057 Creating remote Archivelog file ' standby '

Fal[server, ARC1]: FAL archive failed, and then trace file.

Thu Dec 23 21:42:51 2010

Errors in FILE/OPT/ORA10G/ADMIN/PRIMARY/BDUMP/PRIMARY_ARC1_18406.TRC:

Ora-16055:fal request rejected

Arch:fal Archive failed. Archiver continuing

Thu Dec 23 21:42:51 2010

ORACLE Instance primary-archival Error. Archiver continuing.

Thu Dec 23 21:43:46 2010

Shutting down archive processes

Thu Dec 23 21:43:51 2010

ARCH shutting down

Arc2:archival stopped