This website and this website contain information on the same problem. In order to keep your tables up to date, you must commit your transactions. Use db.commit() to do this.

As mentioned by the post below me, you can remove the need for this by enabling auto-commit. this can be done by running db.autocommit(True)

Also, auto-commit is enabled in the interactive shell, so this explains why you didn t have the problem there.

您不妨检查贵国数据库的交易孤立程度。 你们描述的行为是,如果将行为定在REPEATABLE-READ,你会期望什么。 你不妨将其改为反恐执行局。

Since the original poster of the problem mentions that he is merely querying the database, it cannot be a commit that was forgotten. Inserting a commit seems to be a workaround though since it causes a new transaction to begin; and a new snapshot may need to be established. Still, having to insert a commit before every select doesn t sound like good programming practices to me.

There is no python code to show since the solution lies in correctly configuring the database.

<><>>> http://dev.mysql.com/doc/refman/5.5/en/set-transaction.html。

REPEATABLE READ
This is the default isolation level for InnoDB. For consistent reads, there is an important difference from the READ COMMITTED isolation level: All consistent reads within the same transaction read the snapshot established by the first read. This convention means that if you issue several plain (nonlocking) SELECT statements within the same transaction, these SELECT statements are consistent also with respect to each other. See Section 14.3.9.2, “Consistent Nonlocking Reads”.

READ COMMITTED
A somewhat Oracle-like isolation level with respect to consistent (nonlocking) reads: Each consistent read, even within the same transaction, sets and reads its own fresh snapshot. See Section 14.3.9.2, “Consistent Nonlocking Reads”.

Checking the configured isolation level:

>mysql > SELECT @@GLOBAL.tx_isolation, @@tx_isolation;
+-----------------------+-----------------+
| @@GLOBAL.tx_isolation | @@tx_isolation  |
+-----------------------+-----------------+
| REPEATABLE-READ       | REPEATABLE-READ |
+-----------------------+-----------------+
1 row in set (0.01 sec)

Setting the transaction isolation level to READ-COMMITTED

mysql> SET GLOBAL tx_isolation= READ-COMMITTED ;
Query OK, 0 rows affected (0.00 sec)

mysql> SET SESSION tx_isolation= READ-COMMITTED ;
Query OK, 0 rows affected (0.00 sec)

mysql> SELECT @@GLOBAL.tx_isolation, @@tx_isolation;
+-----------------------+----------------+
| @@GLOBAL.tx_isolation | @@tx_isolation |
+-----------------------+----------------+
| READ-COMMITTED        | READ-COMMITTED |
+-----------------------+----------------+
1 row in set (0.01 sec)

mysql>

并再次提出申请......

页: 1 如下:

conn = MySQLdb.Connect("host", "user", "password")
conn.autocommit(True)

这使你在互动赛事中使用同样的行为。

我不能确切地说,为什么出现这一问题,但我已经测试了3个解决办法,以解决这个问题。

1. 在进行每次盘问之前,建立新的我方(和新方)连接

   cnx = mysql.connector.connect(**config2)
   csr = cnx.cursor(named_tuple=True, buffered=True)
   

我确信,这不是建议的做法,而是解决问题。

2. Commit - either by setting autocommit to true or by manually committing after each query
3. Understand that the problem only occurs with transaction storage engines, so if it is not important to use transactional, you can set the table you are querying to a non transactional type like MyISAM - probably the easiest option

我没有给READ COMMITED增加交易孤立程度,因为我没有审判过,有人声称自己没有工作。