新建oracle的database link时，提示错误“ORA-12169: TNS: 指定为连接标识符的 Net 服务名太长”，
网上查了下，是因为目标oracle是集群，连接字符串过长，超过255个字符，而造成的错误。由此更改。
The maximum length of a net service name is 255 bytes; this limit has been exceeded.
缩减成这种格式，把多余的空格都给去了吧：
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = 211.152.14.210)(PORT = 1521))
(ADDRESS = (PROTOCOL = TCP)(HOST = 211.152.14.209)(PORT = 1521))
(LOAD_BALANCE = yes)
)
(CONNECT_DATA =
(SERVER = DEDICATED)
(SERVICE_NAME = pixel)
)
)
参考文章：http://blog.csdn.net/stevendbaguo/article/details/51793170