python - SQLAlchemy + postgres : (InternalError) current transaction is aborted, 命令被忽略，直到事务 block 结束

Question

我正在尝试保存父/子记录集，并且我想将插入内容包装在一个事务中。我在 postgresql 8.4 中使用 SQLAlchemy。

这是我的代码片段:

def insert_data(parent, child_rows):
    # Start a transaction
    conn = _get_connection()
    tran = conn.begin()

    try:
        sql = get_sql_from_parent(parent)
        res = conn.execute(sql)  # <- Code barfs at this line
        item = res.fetchone() if res else None
        parent_id = item['id'] if ((item) and ('id' in item)) else -1

        if parent_id == -1:
            raise Exception('Parent could not be saved in database')

        # Import children
        for child in child_rows:
            child_sql = get_child_sql(parent_id, child)                        
            conn.execute(child_sql)

        tran.commit()

    except IntegrityError:
        pass  # rollback?

    except Exception as e:
        tran.rollback()
        print "Exception in user code:"
        print '-'*60
        traceback.print_exc(file=sys.stdout)
        print '-'*60

当我调用该函数时，我得到以下堆栈跟踪:

Traceback (most recent call last):
  File "import_data.py", line 125, in <module>
    res = conn.execute(sql)
  File "/usr/local/lib/python2.6/dist-packages/SQLAlchemy-0.7.4-py2.6-linux-x86_64.egg/sqlalchemy/engine/base.py", line 1405, in execute
    params)
  File "/usr/local/lib/python2.6/dist-packages/SQLAlchemy-0.7.4-py2.6-linux-x86_64.egg/sqlalchemy/engine/base.py", line 1582, in _execute_text
    statement, parameters
  File "/usr/local/lib/python2.6/dist-packages/SQLAlchemy-0.7.4-py2.6-linux-x86_64.egg/sqlalchemy/engine/base.py", line 1646, in _execute_context
    context)
  File "/usr/local/lib/python2.6/dist-packages/SQLAlchemy-0.7.4-py2.6-linux-x86_64.egg/sqlalchemy/engine/base.py", line 1639, in _execute_context
    context)
  File "/usr/local/lib/python2.6/dist-packages/SQLAlchemy-0.7.4-py2.6-linux-x86_64.egg/sqlalchemy/engine/default.py", line 330, in do_execute
    cursor.execute(statement, parameters)
InternalError: (InternalError) current transaction is aborted, commands ignored until end of transaction block
...

有谁知道我为什么会收到这个神秘错误 - 我该如何解决？

Answer 1

你能在 postgresql 上激活日志查询吗？ (在 postgresql.conf 中将 min_duration 设置为 0 然后重新启动)。

然后查看你的 postgresql 日志来调试它。