#FASTCUT SHARED DATABASE FREE#
Additionally, running queries on the mirror database can free up resources on the principal. Using database snapshots with database mirroring permits you to make the data on the mirror server accessible for reporting. Using a mirror database that you are maintaining for availability purposes to offload reporting. If disk space permits, you can also maintain end-of-period snapshots indefinitely, allowing queries against the results from these periods for example, to investigate organizational performance. You can then run end-of-period reports on the snapshot. For example, you can create a database snapshot at the end of a given time period (such as a financial quarter) for later reporting. Maintaining historical data for report generation.Ī snapshot can extend user access to data from a particular point in time. Snapshots can be used for reporting purposes.Ĭlients can query a database snapshot, which makes it useful for writing reports based on the data at the time of snapshot creation.
#FASTCUT SHARED DATABASE UPDATE#
Update pattern B reflects an environment in which 80 percent of the original pages are updated during the life of the snapshot.
Update pattern A reflects an environment in which only 30 percent of the original pages are updated during the life of the snapshot.
The following figure illustrates the effects of two contrasting update patterns on the size of a snapshot. As more and more pages are updated in the source database, the size of the file grows. Initially, a sparse file is an essentially empty file that contains no user data and has not yet been allocated disk space for user data. To store the copied original pages, the snapshot uses one or more sparse files. To the user, a database snapshot appears never to change, because read operations on a database snapshot always access the original data pages, regardless of where they reside. The same process is repeated for every page that is being modified for the first time. The snapshot stores the original page, preserving the data records as they existed when the snapshot was created. Before a page of the source database is modified for the first time, the original page is copied from the source database to the snapshot.
Prerequisites for and Limitations on Database Snapshotsĭatabase snapshots operate at the data-page level. Database snapshots are unrelated to snapshot backups, snapshot isolation of transactions, or snapshot replication.
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