前段时间，监控每天晚上跑的ETL程序，发现有个程序报ORA-01002: 提取违反顺序的错误。
Oracle的官方文档里对这个错误的解释是：
Cause: This error means that a fetch has been attempted from a cursor which is no longer valid. Note that a PL/SQL cursor loop implicitly does fetches, and thus may also cause this error. There are a number of possible causes for this error, including: 1) Fetching from a cursor after the last row has been retrieved and the ORA-1403 error returned. 2) If the cursor has been opened with the FOR UPDATE clause, fetching after a COMMIT has been issued will return the error. 3) Rebinding any placeholders in theSQLstatement, then issuing a fetch before reexecuting the statement.
Action: 1) Do not issue a fetch statement after the last row has been retrieved - there are no more rows to fetch. 2) Do not issue a COMMIT inside a fetch loop for a cursor that has been opened FOR UPDATE. 3) Reexecute the statement after rebinding, then attempt to fetch again.