asyncpg.exceptions.DuplicatePreparedStatementError:预准备语句"stmt_5“已存在

Question

函数"runquery“从程序的不同部分被调用。在这种情况下，我从不在查询语句中使用"prepare“。我已经阅读了所有其他关于“准备好的语句已经存在”的问题，并且也尝试了"DEALLOCATE ALL“。但这会导致相反的错误:当下面的错误报告预准备的语句已经存在时，DEALLOCATE ALL会导致报告它不存在。

这是我第一次尝试使用asyncpg运行这种类型的程序。我之前在使用psycopg2时没有这个功能。我应该回到psycopg2吗？

经过如下所示的多次查询后，runquery以错误报告结束：

Could not complete query "select uuid from wos_2017_1.combined_name   where  combined_name = 'xxxxxxx';"  
Traceback (most recent call last):
  File "update2017.py", line 1206, in runquery
    result = await con.fetch(query)
  File "/usr/lib/python3/dist-packages/asyncpg/connection.py", line 268, in fetch
    stmt = await self._get_statement(query, timeout)
  File "/usr/lib/python3/dist-packages/asyncpg/connection.py", line 212, in _get_statement
    state = await protocol.prepare(None, query, timeout)
  File "asyncpg/protocol/protocol.pyx", line 140, in prepare      (asyncpg/protocol/protocol.c:55210)
  File "/usr/lib/python3.5/asyncio/futures.py", line 380, in __iter__
yield self  # This tells Task to wait for completion.
  File "/usr/lib/python3.5/asyncio/tasks.py", line 304, in _wakeup
    future.result() 
  File "/usr/lib/python3.5/asyncio/futures.py", line 293, in result
raise self._exception
asyncpg.exceptions.DuplicatePreparedStatementError: prepared statement "stmt_7" already exists

$ grep -c  INSERT /tmp/y.log
1006
$ grep -c  SELECT /tmp/y.log
1364
$ grep -ci  UPDATE /tmp/y.log
1044
$ grep -ci  delete /tmp/y.log
2548



    import asyncio,asyncpg

    async def make_pool():
         """Create asyncpg connection pool to database"""

         pool = await asyncpg.create_pool(database='wos',
                                 host = 'localhost',
                                 user = 'xx',
                                 password='xxxxxx',


                     port=5432,
                                 min_size=10,
                                 max_size=50)

         return pool

    async def get_con(pool):
        con = await pool.acquire()
        return con

    async def runquery(query):
        con = await get_con(pool)
        try:
            if query.startswith('delete from') or query.startswith('insert'):
                result = await con.execute(query)
            else:
                result = await con.fetch(query)
        except:
            print('Could not complete query "{}"'.format(query))
            print(traceback.format_exc())
            result = None
            exit(1)
        finally:
            await pool.release(con)
        return result, success

Answer 1

这看起来像是asyncpg中的一个bug。请向https://github.com/MagicStack/asyncpg/issues报告，您将在那里获得帮助。