ORA-24808: streaming of lob data is not allowed when using lob buffering
Cause: Attempted to stream lob data via the polling mode or a callback when lob buffering was enabled for the input lob locator.
Action: Lob buffering is useful when reading/writing small amounts of lob data so streaming should not be necessary. Rewrite the OCILobRead/OCILobWrite call so that it does not use streaming. If streaming of data is required, lob buffering should not be used. In this case, flush buffers associated with the input lob locator as necessary, disable buffering on the input lob locator and reissue the OCILobRead/OCILobWrite call.
回答
ORA-24808是Oracle数据库系统中的一个常见错误，它表明在使用LOB缓冲时，不允许进行LOB数据流传输。官方解释是：“ORA-24808缓冲LOBs时不允许数据流传输错误。如果尝试使用数据流传输LOB，则发生此错误。”
此错误的常见原因是，尝试使用LOB缓冲类型，如DBMS_LOB.GETBUFFEROFFSET，DBMS_LOB.SETBUFFER调用之类的函数时，尝试传输LOB数据的行为会导致此错误。另一个原因是在使用缓冲LOB模式时，使用DBMS_LOB.SETSTARTPOS和DBMS_LOB。READ包含的LOB大小可能是另外一个原因。
正确的解决方法是在缓冲情况下禁止数据流操作。应该使用其他缓冲类型，如DBMS_LOB.GETSUBSTRING、DBMS_LOB.GETLENGTH等。另外，应避免使用数据流传输LOB类型，避免出现此错误。