最近从同事那儿接手了一套新环境，备库因为服务器问题已经下架，重新配了一台服务器，所以需要搭一套备库，主库已经配置好了，而且同事已经把在主库把dg broker配好了。
使用dgmgrl来验证，只有主库孤零零的在那儿。
DGMGRL> show configuration;
Configuration - dg_test
Protection Mode: MaxPerformance
Databases:
stest - Primary database
Fast-Start Failover: DISABLED
Configuration Status:
SUCCESS
备库搭建的过程也还算顺利，中间也经历了一些小插曲，不过问题最后都得到解决。duplicate同步之后，开始启用dg broker，因为主库的dg broker配置已经有了，所以直接添加备库。
数据库db_name为test,主库的unique_name为stest,备库为s2test
DGMGRL> add database s2test as
connect identifier is s2test
maintained as physical;
想必添加完之后就开始enable database就大功告成，没想到还是有问题。
DGMGRL> show database verbose s2test
Database - s2test
Database Status:
。。。
DGM-17016: failed to retrieve status for database "s2tlest"
ORA-16664: unable to receive the result from a database
这个时候借助oerr来看看错误信息
$ oerr ora 16664
16664, 0000, "unable to receive the result from a database"
// *Cause: During execution of a command, a database in the Data Guard
// broker configuration failed to return a result.
// *Action: Check Data Guard broker logs for the details of the failure.
// Ensure network communication is working properly amongst the
// members of the configuration. Fix any possible network problems
// and reissue the command.
dg broker的错误解释
$ oerr dgm 17016
17016, 00000, "failed to retrieve status for database \"%s\""
// *Cause: DGMGRL could not retrieve the StatusReport property from the given
// database and thus could not report the database status.
// *Action: See accompanying messages for details.
看来没有得到更多的信息，就从备库的dg broker日志中查看，
######dataguard log
Warning: Property 'LogArchiveFormat' has inconsistent values:METADATA='%t_%s_%r.dbf', SPFILE='(missing)', DATABASE='%t_%s_%r.dbf'
Failed to send message to site stest. Error code is ORA-16501.
10/10/2015 14:04:36
Warning: Property 'ArchiveLagTarget' has inconsistent values:METADATA='0', SPFILE='', DATABASE='0'
Warning: Property 'LogArchiveMaxProcesses' has inconsistent values:METADATA='4', SPFILE='', DATABASE='4'
Warning: Property 'LogArchiveMinSucceedDest' has inconsistent values:METADATA='1', SPFILE='', DATABASE='1'
SPFILE is missing value for property 'LogArchiveTrace' with sid='test'
Warning: Property 'LogArchiveTrace' has inconsistent values:METADATA='0', SPFILE='(missing)', DATABASE='0'
SPFILE is missing value for property 'LogArchiveFormat' with sid='test'
Warning: Property 'LogArchiveFormat' has inconsistent values:METADATA='%t_%s_%r.dbf', SPFILE='(missing)', DATABASE='%t_%s_%r.dbf'
Failed to send message to site stest. Error code is ORA-16501.
从日志来看备库是连接主库有问题，
$ oerr ora 16501
16501, 00000, "the Data Guard broker operation failed"
// *Cause: The Data Guard broker operation failed.
// *Action: See accompanying messages for details.
如此来看主库连接备库有问题，备库说连接主库有问题，查看了好几遍网络配置，都没有发现任何问题。
在主库中使用dgmgrl来查看更多的细节信息。
DGMGRL> show database verbose stest;
Database - stest
Role: PRIMARY
Intended State: TRANSPORT-ON
Instance(s):
test
Properties:
DGConnectIdentifier = 'test01'
ObserverConnectIdentifier = ''
LogXptMode = 'ASYNC'
DelayMins = '0'
Binding = 'optional'
MaxFailure = '0'
MaxConnections = '1'
ReopenSecs = '300'
NetTimeout = '30'
RedoCompression = 'DISABLE'
LogShipping = 'ON'
PreferredApplyInstance = ''
ApplyInstanceTimeout = '0'
ApplyParallel = 'AUTO'
StandbyFileManagement = 'AUTO'
ArchiveLagTarget = '0'
LogArchiveMaxProcesses = '2'
LogArchiveMinSucceedDest = '1'
DbFileNameConvert = '/U01/app/oracle/oradata/test, /U01/app/oracle/oradata/test'
LogFileNameConvert = '/U01/app/oracle/oradata/test, /U01/app/oracle/oradata/test'
FastStartFailoverTarget = ''
InconsistentProperties = '(monitor)'
InconsistentLogXptProps = '(monitor)'
SendQEntries = '(monitor)'
LogXptStatus = '(monitor)'
RecvQEntries = '(monitor)'
SidName = 'test'
StaticConnectIdentifier = '(DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=test01.cyou.com)(PORT=1521))(CONNECT_DATA=(SERVICE_NAME=stest_DGMGRL)(INSTANCE_NAME=test)(SERVER=DEDICATED)))'
StandbyArchiveLocation = '/U01/app/oracle/arch'
AlternateLocation = ''
LogArchiveTrace = '0'
LogArchiveFormat = '%t_%s_%r.dbf'
TopWaitEvents = '(monitor)'
Database Status:
SUCCESS
查看备库的
DGMGRL> show database verbose s2test
Database - s2test
Role: PHYSICAL STANDBY
Intended State: APPLY-ON
Transport Lag: (unknown)
Apply Lag: (unknown)
Real Time Query: OFF
Instance(s):
test
Properties:
DGConnectIdentifier = 's2test'
ObserverConnectIdentifier = ''
LogXptMode = 'ASYNC'
DelayMins = '0'
Binding = 'optional'
MaxFailure = '0'
MaxConnections = '1'
ReopenSecs = '300'
NetTimeout = '30'
RedoCompression = 'DISABLE'
LogShipping = 'ON'
PreferredApplyInstance = ''
ApplyInstanceTimeout = '0'
ApplyParallel = 'AUTO'
StandbyFileManagement = 'AUTO'
ArchiveLagTarget = '0'
LogArchiveMaxProcesses = '4'
LogArchiveMinSucceedDest = '1'
DbFileNameConvert = ''
LogFileNameConvert = ''
FastStartFailoverTarget = ''
InconsistentProperties = '(monitor)'
InconsistentLogXptProps = '(monitor)'
SendQEntries = '(monitor)'
LogXptStatus = '(monitor)'
RecvQEntries = '(monitor)'
SidName = 'test'
StaticConnectIdentifier = '(DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=stest.cyou.com)(PORT=1521))(CONNECT_DATA=(SERVICE_NAME=s2test_DGMGRL)(INSTANCE_NAME=test)(SERVER=DEDICATED)))'
StandbyArchiveLocation = '/U01/app/oracle/product/11.2.3/db_1/dbs/arch'
AlternateLocation = ''
LogArchiveTrace = '0'
LogArchiveFormat = '%t_%s_%r.dbf'
TopWaitEvents = '(monitor)'
Database Status:
DGM-17016: failed to retrieve status for database "s2test"
ORA-16664: unable to receive the result from a database
最后查看mos，发现一篇文章比较贴近，不过描述的问题原因还是有些差别。
Data Guard Standby Database Broker Configuration error DGM-17016: failed to retrieve status for database (文档 ID 1631552.1)
进一步排除，排除了防火墙的影响，甚至考虑重启一下数据库，结果重启库的时候还确实有问题
SQL> startup
ORACLE instance started.
Total System Global Area 1.5734E+10 bytes
Fixed Size 2243832 bytes
Variable Size 1375732488 bytes
Database Buffers 1.4328E+10 bytes
Redo Buffers 27852800 bytes
Database mounted.
ORA-04031: unable to allocate 32 bytes of shared memory ("shared pool","ALTER
DATABASE OPEN","SQLA","tmp")
不过这个和dg broker的问题是没有关系的，是sga配置的shared pool太小，process配置了3000，结果就导致启动的时候shared pool过小起不来了。
备库数据库启动了，但是dg broker的验证还是照样有问题，这个时候就仔细比对show database verbose中的信息
发现主库的信息有一点特别。
DGMGRL> show database verbose stest;
Database - stest
Role: PRIMARY
Intended State: TRANSPORT-ON
Instance(s):
test
Properties:
DGConnectIdentifier = 'test01'
特别就特别在这个地方，这个地方最好应该是和db_unique_name一致，结果设置成了test01,备库中网络服务中也没有配置这个服务名
简单修改一下，修改为db_unique_name
DGMGRL> edit database stest set property DGConnectIdentifier ='stest';
Property "dgconnectidentifier" updated
再次查看就没有问题了。
DGMGRL> show configuration;
Configuration - dg_test
Protection Mode: MaxPerformance
Databases:
stest - Primary database
s2test - Physical standby database
Fast-Start Failover: DISABLED
Configuration Status:
SUCCESS
可能之前的同事都是习惯使用db_name来作为主库的dg配置，结果自己还纠结了半天，排除了不少的因素，最后发现竟然是这么一个细小的地方，修改为db_unique_name就可以了，可见对于这些小的细节上最好还是能够有一个统一的标准规范，这样也好规范大家，避免这类问题带来的困扰。