Getting a Consistent View of the Database

A consistent view of the database is necessary, because DBCC CHECKDB must analyze all allocated pages in the database and check the various links between structures on multiple pages. This means that the pages being analyzed (that is, the whole database) cannot change while the consistency checks are running; otherwise DBCC CHECKDB reports all kinds of incorrect results. As DBCC CHECKDB cannot read all the allocated pages in the database instantaneously, this means the consistent view of the database must be maintained for the duration of the consistency checks. It is also not enough for the database to be simply frozen in time—the consistent view of the database must also be transactionally consistent ...

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