Question

我在将Oracle数据库使用的pyodbc遇到问题。我可以选择结果返回的语句，但是当我尝试更新记录时，该程序似乎在“ conn.execute（query）”行中挂起，没有错误消息。我必须强行退出该应用程序。

运行select语句检索预期结果。更新相同记录将挂起。我还在其他应用程序上使用了此定义，而在选择和更新正常工作的MSSQL DB上没有问题。我还检查了用户/通行证是否具有读写权限

import pyodbc

def connect_odbc(conn_str, query, commit=False):
    """
    Returns result set from connection string.
    If commit is set to true, it will write to DB as well
    """
    if commit:
        conn = pyodbc.connect(conn_str)
        cursor = conn.cursor()
        cursor.execute(query)  ### <--- Program hangs here
        cursor.commit()
        cursor.close()
        return True
    else:
        conn = pyodbc.connect(conn_str)
        cursor = conn.cursor()
        cursor.execute(query)
        results = cursor.fetchall()
        cursor.close()

        return results

## Main Program ##
query = "select * from multishipdtl where cartonid = '100000000060506';"
queryupdate = "update multishipdtl set trackid='88888888' where cartonid = '100000000060506';"

conn_str = '''DSN=syntest;UID=userid;PWD=userpass'''
results = connect_odbc(conn_str, query)  ### This connects ok with expected results

connect_odbc(conn_str, queryupdate, commit=True)  ### Update statement hangs

Answer 1

如果程序在执行cursor.execute("UPDATE ...")时挂起，我首先要检查的是它是否在等待数据库响应：How do you show SQL executing on an Oracle database?

如果数据库显示您的会话正在运行UPDATE，则很可能是因为另一个事务锁定了您要更新的行-请参见Oracle database is hanging infinitly in UPDATE queries;否则为check V$SESSION's status and wait_time, and V$SESSION_WAIT's event。您可能还想尝试通过从SQL客户端（没有Python）运行UPDATE来重现此问题。
如果不是数据库，请检查Python的调用堆栈以获取提示。当您通过按CTRL + C中止该程序时，应该将其打印出来，否则请打印-尝试Showing the stack trace from a running Python application

ODBC trace log可能也有帮助。

通过pyodbc更新Oracle DB挂起

1 个答案: