Checkpoint--相关问题

Checkpoint是实例级别还是数据库级别？

答：数据库级别，在SQL Server关闭时，会对所有数据库逐一提交checkpoint

 

测试代码

USE DB0002

GO

CHECKPOINT

GO

SELECT * INTO TB1001 FROM sys.all_columns

GO

SELECT COUNT(1) FROM sys.dm_os_buffer_descriptors

WHERE is_modified=1

AND database_id=DB_ID()

GO

USE DB005

GO

CHECKPOINT

GO

USE DB0002

GO

SELECT COUNT(1) FROM sys.dm_os_buffer_descriptors

WHERE is_modified=1

AND database_id=DB_ID()

GO

 

CHECKPOINT前后DB0002的脏页数据一样

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CHECKPOINT会将未提交数据写入磁盘么？

答案：会，CHECKPOINT提交时，将标记所有脏页并写入到磁盘中，不考虑是否有未提交数据，对未提交的数据由日志负责处理(UNDO)