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【DM版本】:8.4
【操作系统】：linux KylinOS-V10 SP3
【CPU】:8
【问题描述】*：执行Python脚本，通过SQLAlchemy查询报错，应该如何优化代码
代码：
for chunk in pd.read_sql_table(table_name.lower(), engine,chunksize=500000):
....
报错：
Traceback (most recent call last):
File "/root/miniconda3/lib/python3.10/site-packages/sqlalchemy/engine/base.py", line 1963, in _exec_single_context
self.dialect.do_execute(
File "/root/miniconda3/lib/python3.10/site-packages/dmSQLAlchemy-2.0.5-py3.10.egg/dmSQLAlchemy/base.py", line 1900, in do_execute
File "/root/miniconda3/lib/python3.10/site-packages/sqlalchemy/engine/default.py", line 943, in do_execute
cursor.execute(statement, parameters)
dmPython.DatabaseError: [CODE:-7120]Undo record version too old, user record unavailable
环境：
dmPython 2.5.22
dmSQLAlchemy 2.0.5
SQLAlchemy 2.0.41