MySQL8.0.12中DDL新增instant语法,只修改元数据,不需要锁表,这里最重要的改进是add column instant(即刻加列),在8.0之前版本,Online DDL下,加字段可以使用inplace方式,虽然不会长时间阻塞写入,但其实还是需要rebuild重构表,这有几个负作用: 1. 对于大表,变更时间长 2. 需要额外的磁盘空间 3. 会消耗大量的CPU,...
mysql> create table student(id int,name varchar(10),sex enum('男','nv'),age tinyint,cometime datetime);Query OK, 0 rows affected (0.03 sec)#2.插入数据mysql> insert into student values('-12573','邱导','男','-18',now());Query OK, 1 row affected (0.00 sec)#3.查看数据...
Concurrent queries are permitted during all online DDL operations. You can specifyLOCK=SHARED to assert that concurrent queries are permitted during a DDL operation. MySQL automatically permits concurrent queries when possible. The “Notes” column provides additional information and explains exceptions and...
Re: How to Implement SQL DDL queries in java? warren charlot September 11, 2010 12:17AM Re: How to Implement SQL DDL queries in java? Chandan Balu September 11, 2010 12:32AM Sorry, you can't reply to this topic. It has been closed....
specify LOCK=NONE to assert that concurrent DML is permitted during the DDL operation. MySQL automatically permits concurrent DML when possible. Concurrent queries are permitted during all online DDL operations. You can specify LOCK=SHARED to assert that concurrent queries are permitted during a DDL ...
“Allows Concurrent Queries?”列显示了哪些DDL操作允许查询表操作同时进行, 优选值是“Yes”。并发查询允许在所有在线DDL操作。它显示为“Yes”。你可以指定LOCK=SHARED声明并发查询在DDL期间是允许的,但MySQL自动允许这种级别的并发,如果可能。 “Notes”列解释其他列值为“Yes/No”的任何例外,例如当答案取决于一个...
在OGG for MySQL双主架构中,如何避免数据冲突? 相关文章 OGG有传统的经典架构,也有最新的微服务,2个都可以远程捕获和应用数据,对数据库服务器是0侵入,而传统的经典架构是纯命令行模式,最新的微服务架构是图形化界面操作,几乎所有操作都可以在界面进行。 相关文章可以参考: 使用OGG for MySQL微服务快速双向同步RDS数据...
Applications that access the table are more responsive because queries and DML operations on the table can proceed while the DDL operation is in progress. Reduced locking and waiting for MySQL server resources leads to greater scalability, even for operations that are not involved in the DDL ...
Concurrent queries are permitted with ALGORITHM=COPY for tables partitioned by HASH or LIST, as MySQL copies the data while holding a shared lock. DROP PARTITION No Yes* Yes* ALGORITHM=INPLACE, LOCK={DEFAULT|NONE|SHARED|EXCLUSIVE} is supported. Does not copy data for tables partitioned by ...
SSMA - Convert adhoc DML and DDL queriesSanto, Nuno 0 Reputation points Jul 25, 2024, 1:03 AM Hello, Does Microsoft SQL Server Migration Assistant (SSMA) provide a way to convert an ah-doc DML or DDL query from DB2 z/OS syntax to MS SQL Server? By other means, I have an ...