ORA-20000：ORU-10027：buffer overflow,limit of 2000 bytes.

　　在sql*plus 等工具使用 dbms_output函数进行输出时，如若输出的内容很多，会出现ORA-20000：ORU-10027：buffer overflow,limit of 2000 bytes.错误，这是由于输出缓冲区溢出造成的，有两种方法来解决！

　　1、增加输出缓冲区大小

　　SET SERVEROUTPUT ON SIZE 1000000;

　　2、DBMS_OUTPUT缓冲区设置限制

　　在输出的最开始运行DBMS_OUTPUT.ENABLE(buffer_size => null)，说明不启用输出限制

以下为oracle DBMS_OUTPUT.ENABLE的说明

procedure enable (buffer_size in integer default 20000);
  pragma restrict_references(enable,WNDS,RNDS);
  --  Enable calls to put, put_line, new_line, get_line and get_lines.
  --    Calls to these procedures are noops if the package has
  --    not been enabled.  Set default amount of information to buffer.
  --    Cleanup data buffered from any dead sessions.  Multiple calls to
  --    enable are allowed.
  --  Input parameters:
  --    buffer_size
  --      Amount of information, in bytes, to buffer.  Varchar2, number and
  --      date items are stored in their internal representation.  The
  --      information is stored in the SGA. An error is raised if the
  --      buffer size is exceeded.  If there are multiple calls to enable,
  --      then the buffer_size is generally the largest of the values
  --      specified, and will always be >= than the smallest value
  --      specified.  Currently a more accurate determination is not
  --      possible.  The maximum size is 1,000,000, the minimum is 2000.

  procedure disable;
  pragma restrict_references(disable,WNDS,RNDS);
  --  Disable calls to put, put_line, new_line, get_line and get_lines.
  --    Also purge the buffer of any remaining information.