Query OK, 0 rows affected (0.00 sec)、创建测试用的表和插入必要的测试数据: session a: db01> create table t1( idint not null primary key, age int ); Query OK, 0 rows affected (0.03 sec) session a: db01> insert into t1 values(1,1),(2,2); Query OK, 2 rows affected (0.02 sec...
mysql tablesinuse1,locked1LOCKWAIT2lockstruct(s),heap size1136,1rowlock(s)MySQL thread id123,OSthread handle1234567890,query id98765localhost rootUPDATEusersSETbalance=balance-100WHEREuser_id=1;***(1)WAITINGFORTHISLOCKTOBEGRANTED:RECORDLOCKSspace id56page no10n bits72index`PRIMARY`oftable`test`....
设置UNDO_RETENTION等于或大于MAX(MAXQUERYLEN)以避免ORA-1555 errors 此视图有几个已知的bug 10. 统计undo的生成率和最大查询运行时间: CREATE OR REPLACE VIEW vw_undostat AS SELECT * FROM v$undostat WHERE txncount != 0; 11. undo大小的估算: Undo Space in Bytes = (UR * UDBPS * DB_Block Siz...
mysql_query("BEGIN TRANSACTION"); //do stuff here // could be INSERT, or UPDATE, or DELETE or call SP that does these. // if anything fails then mysql_query("ROLLBACK"); // else mysql_query("COMMIT"); ~~~ Using mysqli interface. ~~~ $link = mysqli_connect('localhost','...
For example, in a registration system, you might rollback a transaction if a unique constraint is violated. For more Practice: Solve these Related Problems: Write a MySQL query that attempts to insert a duplicate primary key in a table and rolls back the transaction upon failure. ...
Irreversibility Warning.Once `ROLLBACK` is executed, the changes are irreversibly undone. Make sure that this operation is intentionally performed. SQL Upskilling for Beginners Gain the SQL skills to interact with and query your data. Start Learning for Free...
--设置MySQL自动提交为0; set autocommit=0;设置关闭了MySQL的自动提交,插入数据是虚拟表,后可用 rollback; 撤销,再使用 commit; 真实提交数。 使用commit后,是不可撤销下的(持久性) mysql>setautocommit=0; Query OK,0rows affected mysql>insertintouservalues(3,'c',3000);1062-Duplicate entry'3'forkey'...
$result= mysql_query($procedure);if(!$result) { //rollback occureddosomething } Is there a way to detect rollback in MySQL? Am I missing something? Any reply will be appreciated. Thanks for reading. Thanks to your advices I fixed this problem. Here's what I did: ...
ERROR 2013 (HY000): Lost connection to MySQL server during query No connection. Trying to reconnect... Connection id: 9 Current database: University +---+ | 1 | +---+ | 1 | +---+ It indeed disconnects the client session.
in set (0.01 sec)mysql> use testdb;Database changedmysql> begin ;Query OK, 0 rows affected (0.00 sec)mysql> select * from test1;+---+---+| id | name |+---+---+| 1 | 1wdrt5 || 2 | 2edft6 |+---+---+2 rows in set (0.00 sec)mysql> select * from test1 where ...