Jianliang,
I tested that with two mysql clients, and it appeared to work ok. Check with
SHOW CREATE TABLE tablename
what is the type of your table. Is it MyISAM?
Also put the line
log
to the [mysqld] section of your my.cnf and restart mysqld. Then you will see
all received queries in the file 'hostname'.log in your datadir. Check from
it what SQL queries your clients actually send to the mysqld server.
Regards,
Heikki
Innobase Oy
Below my test:
CLIENT A:
heikki@hundin:~/mysql/client> mysql test
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 1 to server version: 3.23.53-log
Type 'help;' or '\h' for help. Type '\c' to clear the buffer.
mysql> set autocmmit = 0;
ERROR 1064: You have an error in your SQL syntax. Check the manual that
corresp
onds to your MySQL server version for the right syntax to use near
'autocmmit =
0' at line 1
mysql> set autocommit = 0;
Query OK, 0 rows affected (0.00 sec)
mysql> create table zhao (a int not null, b int, primary key (a)) type =
innodb;
Query OK, 0 rows affected (0.11 sec)
mysql> insert into zhao values (10, 20);
Query OK, 1 row affected (0.00 sec)
mysql> commit
-> ;
Query OK, 0 rows affected (0.00 sec)
mysql> update zhao set b = 100;
Query OK, 1 row affected (0.01 sec)
Rows matched: 1 Changed: 1 Warnings: 0
mysql>
CLIENT B:
heikki@hundin:~/mysql/client> mysql test
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 2 to server version: 3.23.53-log
Type 'help;' or '\h' for help. Type '\c' to clear the buffer.
mysql> select * from zhao;
+----+------+
| a | b |
+----+------+
| 10 | 20 |
+----+------+
1 row in set (0.00 sec)
mysql> select * from zhao;
+----+------+
| a | b |
+----+------+
| 10 | 20 |
+----+------+
1 row in set (0.00 sec)
mysql> select * from zhao;
+----+------+
| a | b |
+----+------+
| 10 | 20 |
+----+------+
1 row in set (0.00 sec)
mysql> set autocommit = 0;
Query OK, 0 rows affected (0.00 sec)
mysql> select * from zhao;
+----+------+
| a | b |
+----+------+
| 10 | 20 |
+----+------+
1 row in set (0.00 sec)
mysql> commit;
Query OK, 0 rows affected (0.00 sec)
mysql> select * from zhao;
+----+------+
| a | b |
+----+------+
| 10 | 20 |
+----+------+
1 row in set (0.00 sec)
mysql>
----- Original Message -----
From: "Jianliang Zhao" <[EMAIL PROTECTED]>
To: "Heikki Tuuri" <[EMAIL PROTECTED]>; "Mark Matthews"
<[EMAIL PROTECTED]>
Cc: <[EMAIL PROTECTED]>
Sent: Tuesday, October 08, 2002 7:40 PM
Subject: RE: transaction isolation level
Thanks for all your help. Then it's more confusing to me. I opened two MySql
windows and set autocommit=0 and then update one column and then issue the
command COMMIT in one window, in the other MySql window, I queried the
column and saw the change immediately.
I also did the same thing with one MySql window and one JDBC client(my
testcase), and the testcase can see the change immediately.
In either case, instead of issuing COMMIT, if I issue ROLLBACK, the change
will be rolled back. (Just to make sure the auto commit is not on).
Here is my testcase:
import java.sql.*;
import java.util.Properties;
import com.mysql.jdbc.Driver;
public class TestMySql {
public static void main(String[] args) throws Exception {
Driver.class.getName();
Properties props = new Properties();
props.setProperty("user", "root");
props.setProperty("password", "geneva");
Connection conn =
DriverManager.getConnection("jdbc:mysql://localhost/test", props);
Statement stmt = conn.createStatement();
ResultSet rs = stmt.executeQuery("select * from testtable");
while(rs.next()) {
System.out.println(rs.getInt(1));
}
System.out.println("Please update the table TESTTABLE...");
System.in.read();
rs = stmt.executeQuery("select * from testtable");
while(rs.next()) {
System.out.println(rs.getInt(1));
}
}
}
-----Original Message-----
From: Heikki Tuuri [mailto:[EMAIL PROTECTED]]
Sent: 2002?10?8? 0:22
To: Mark Matthews
Cc: [EMAIL PROTECTED]
Subject: Re: transaction isolation level
Hi!
----- Original Message -----
From: "Mark Matthews" <[EMAIL PROTECTED]>
Newsgroups: mailing.database.mysql
Sent: Tuesday, October 08, 2002 5:07 AM
Subject: Re: transaction isolation level
> Jianliang Zhao wrote:
...
> >>I am connecting to MySql 3.23(innodb) with
> >>mysql-connector-java-2.0.14-bin.jar. I set the global transaction
> >>isolation level to READ COMMITTED. However, I still couldn't see the
> >>committed changes through JDBC client. Does anyone know about this
> >>issue?
...
> The isolation level of READ_COMMITTED has no effect currently in MySQL,
> unless you're using BDB tables...InnoDB runs either as REPEATABLE_READ
> or SERIALIZABLE, and converts everthing else to REPEATABLE_READ, because
> it can do REPATABLE_READ as fast (or faster) than most other DB's
> READ_COMMITTED.
I have to correct that BDB always runs at the SERIALIZABLE isolation level.
The default for InnoDB is REPEATABLE READ, and you can enhance it to
SERIALIZABLE with the
SET [GLOBAL | SESSION] TRANSACTION ISOLATION LEVEL
{ READ UNCOMMITTED | READ COMMITTED | REPEATABLE READ | SERIALIZABLE }
SQL command. Since MyISAM uses table locking, we can say that MyISAM always
runs at the SERIALIZABLE level.
The command SHOW VARIABLES currently shows the MySQL default isolation level
as READ-COMMITTED, but it has no effect on any of the table handlers.
Version 4.0.5 will probably feature a new InnoDB isolation level READ
COMMITTED. I will probably at the same time change the MySQL default
isolation level to REPEATABLE READ. You can then lower the InnoDB isolation
level by the command
SET [GLOBAL | SESSION] TRANSACTION ISOLATION LEVEL ...
Users porting from Oracle and other databases will find READ COMMITTED a
useful level.
> -Mark
Best regards,
Heikki Tuuri
Innobase Oy
---
InnoDB - transactions, row level locking, and foreign key support for MySQL
See http://www.innodb.com, download MySQL-Max from http://www.mysql.com
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