A method for optimizing index, comprising: checking , by a master database node, if role information of an index matches role information of the master database node, when the index is added into the master database node; updating , by the master database node, database information by using the index when the role information of the index matches the role information of the master database node, wherein the method further is characterized by : checking , by the master database node, if the role information of the index matches the role information of the master database node, when a record need to be inserted into a table associated with the index; generating dummy redo information for the record when the role information of the index does not match the role information of the master database node; and wherein the method further comprises: checking , by the master database node, if the role information of the index matches the role information of a subscriber database node; sending , by the master database node, the dummy redo information to the subscriber database node when the role information of the index matches the role information of the subscriber database node. checking , by a master database node, if role information of an index matches role information of the master database node, when the index is added into the master database node; updating , by the master database node, database information by using the index when the role information of the index matches the role information of the master database node, wherein the method further is characterized by : checking , by the master database node, if the role information of the index matches the role information of the master database node, when a record need to be inserted into a table associated with the index; generating dummy redo information for the record when the role information of the index does not match the role information of the master database node; and wherein the method further comprises: checking , by the master database node, if the role information of the index matches the role information of a subscriber database node; sending , by the master database node, the dummy redo information to the subscriber database node when the role information of the index matches the role information of the subscriber database node. checking , by the master database node, if the role information of the index matches the role information of the master database node, when a record need to be inserted into a table associated with the index; generating dummy redo information for the record when the role information of the index does not match the role information of the master database node; and wherein the method further comprises: checking , by the master database node, if the role information of the index matches the role information of a subscriber database node; sending , by the master database node, the dummy redo information to the subscriber database node when the role information of the index matches the role information of the subscriber database node. checking , by the master database node, if the role information of the index matches the role information of a subscriber database node; sending , by the master database node, the dummy redo information to the subscriber database node when the role information of the index matches the role information of the subscriber database node. <EOS>