Oracle 11g active standby不能实时同步解决

环境：Oracle  linux  5.5+Oracle  11.2.0.2

发现一套1一主二从的Oracle 11.2.0.2主从库的一个active standby无法实时同步。

查看dgmgrl配置没有问题，日志同步状态为实时同步：    LogXptMode                      = 'SYNC'

DGMGRL> show database verbose s2bzcge;
Database - s2bzcge
  Role:            PHYSICAL STANDBY
  Intended State:  APPLY-ON
  Transport Lag:   0 seconds
  Apply Lag:       0 seconds
  Real Time Query: ON
  Instance(s):
    bzcge
  Properties:
    DGConnectIdentifier             = '(description =(address_list =(address = (protocol = tcp)(host = *.*.*.* )(port = 1111)))(connect_data =(service_name = service)))'
    ObserverConnectIdentifier       = ''
    LogXptMode                      = 'SYNC'
    DelayMins                       = '0'
    Binding                         = 'optional'
    MaxFailure                      = '0'
    MaxConnections                  = '1'
    ReopenSecs                      = '300'
    NetTimeout                      = '30'
    RedoCompression                 = 'DISABLE'
    LogShipping                     = 'ON'
    PreferredApplyInstance          = ''
    ApplyInstanceTimeout            = '0'
    ApplyParallel                   = 'AUTO'
    StandbyFileManagement           = 'AUTO'
    ArchiveLagTarget                = '1800'
    LogArchiveMaxProcesses          = '10'
    LogArchiveMinSucceedDest        = '1'
    DbFileNameConvert               = ''
    LogFileNameConvert              = ''
    FastStartFailoverTarget         = ''
    InconsistentProperties          = '(monitor)'
    InconsistentLogXptProps         = '(monitor)'
    SendQEntries                    = '(monitor)'
    LogXptStatus                    = '(monitor)'
    RecvQEntries                    = '(monitor)'
    SidName                         = 'bzcge'
    StaticConnectIdentifier         = '(DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=0.0.0.0)(PORT=1111))(CONNECT_DATA=(SERVICE_NAME=s2bzcge_DGMGRL)(INSTANCE_NAME=bzcge)(SERVER=DEDICATED)))'
    StandbyArchiveLocation          = '/U02/oradata/bzcge/archive'
    AlternateLocation               = ''
    LogArchiveTrace                 = '0'
    LogArchiveFormat                = '%t_%s_%r.dbf'
    TopWaitEvents                   = '(monitor)'

Database Status:
SUCCESS

怀疑是配置问题，对比了另外一个从库，配置没问题，把库删除掉，重新加入dgmgrl。

remove database s2bzcge;

add database s2bzcge as connect identifier is "(description =(address_list =(address = (protocol = tcp)(host = 10.1.2.1 )(port = 1111)))(connect_data =(service_name = bzcge)))" maintained as physical;

enable database s2bzcge;
edit database s2bzcge set property LogXptMode = 'SYNC';

remove database s1bzcge;

add database s1bzcge as connect identifier is "(description =(address_list =(address = (protocol = tcp)(host = 10.1.2.2 )(port = 1111)))(connect_data =(service_name = bzcge)))" maintained as physical;

enable database s1bzcge;

edit database s2bzcge set property LogXptMode = 'SYNC';

但是这个问题依旧存在。

日志数是够的，主库日志组为9，从库的standby日志数为10。

查询异常库的v$standby_log，注意标黄的列。此处DBID是没有有价值的数据的。

select * from v$standby_log;

查询正常从库的v$standby_log，注意标黄的行。此处有一行数据是和其他的数据不同的。

select * from v$standby_log;

推测是之前建从库的同事加的standby  redo  log加的有问题，导致无法支持主从实时同步。因此考虑删除现有的standby  redo  log，重新增加。

首先要退出日志应用，否则无法删除：

recover managed standby database cancel;

删除所有日志组：

alter database drop logfile group 32;
alter database drop logfile group 33;
alter database drop logfile group 34;
alter database drop logfile group 35;
alter database drop logfile group 36;
alter database drop logfile group 37;
alter database drop logfile group 38;
alter database drop logfile group 39;
alter database drop logfile group 40;
alter database drop logfile group 31;

重新添加日志组：

alter database add standby logfile group 30 '/U02/oradata/bzcge/sredo30.rdo' size 500m;
alter database add standby logfile group 31 '/U02/oradata/bzcge/sredo31.rdo' size 500m;
alter database add standby logfile group 32 '/U02/oradata/bzcge/sredo32.rdo' size 500m;
alter database add standby logfile group 33 '/U02/oradata/bzcge/sredo33.rdo' size 500m;
alter database add standby logfile group 34 '/U02/oradata/bzcge/sredo34.rdo' size 500m;
alter database add standby logfile group 35 '/U02/oradata/bzcge/sredo35.rdo' size 500m;
alter database add standby logfile group 36 '/U02/oradata/bzcge/sredo36.rdo' size 500m;
alter database add standby logfile group 37 '/U02/oradata/bzcge/sredo37.rdo' size 500m;
alter database add standby logfile group 38 '/U02/oradata/bzcge/sredo38.rdo' size 500m;
alter database add standby logfile group 39 '/U02/oradata/bzcge/sredo39.rdo' size 500m;
alter database add standby logfile group 40 '/U02/oradata/bzcge/sredo40.rdo' size 500m;
alter database add standby logfile group 41 '/U02/oradata/bzcge/sredo41.rdo' size 500m;

查询异常库的v$standby_log，注意标黄的列。此处DBID依然是没有有价值的数据的。

select * from v$standby_log;

恢复日志应用：

ALTER DATABASE RECOVER MANAGED STANDBY DATABASE USING CURRENT LOGFILE DISCONNECT FROM SESSION;

在 主库做一下日志切换，看有什么结果

sqlplus "/as sysdba"

alter system switch logfile;

查询异常库的v$standby_log，注意标黄的行，这个时候，有数据产生了。

select * from v$standby_log;

再在主库做一下日志切换，看有什么结果

sqlplus "/as sysdba"

alter system switch logfile;

查询异常库的v$standby_log，注意标黄的行，这个时候，日志从30号切到31号了。

select * from v$standby_log;

这个时候再去测试，发现主从库可以正常实时同步了，至此该问题解决。

再次碰到该问题，发现是主库的redo log 比从库的standby redo log物理大小大引起的。将从库redo log改为和主库最大的redo log物理大小一样即可