当使用OCCI时，删除将永远运行

Question

同一行：

DELETE(SELECT * FROM tablename WHERE id=12)

在上，正常运行，使用occi需要花费很长时间。

我已经检查了查询"SELECT * FROM tablename WHERE id=12“是否匹配一组非空行。

更具体地说，我使用了以下语法：

oracle::occi::Statement *deleteStm = con->createStatement("DELETE(SELECT * FROM tablename WHERE id=12)");
oracle::occi::ResultSet *rs = deleteStm->executeQuery();

Answer 1

我怀疑在您的情况下，您只是得到了未提交的事务。它是这样的：

session1                   session2
DELETE ...                                        table/rows is locked

                           SELECT * FROM ...      you will see all data

                           DELETE ...             and now you will wait and wait
                                                  until lock is released

COMMIT;
                           SELECT * FROM ...      now resultset is empty

我强烈建议阅读数据并发性和一致性