This section covers the following topics:Ĭhecking Database Integrity Using the Management PortalĬhecking Database Integrity Using the ^Integrity Utility You can run an integrity check from the Management Portal or using the ^Integrity utility in a Terminal window. Regular integrity checks provide a means by which the origin of any structural integrity problems that are found can be more accurately pinpointed in time, increasing the likelihood of identifying the root cause.Īn integrity check lets you verify the integrity of all globals in selected databases, or of selected globals stored in a single specified database. Integrity check can detect corruption before users encounter it, giving time to make a plan before users are impacted. Integrity check can be integrated into your backup strategy to ensure that at the time of backup, the copy of the database was intact and that no errors were introduced during the backup itself, as discussed in External Backup in the “Backup and Restore” chapter. The benefits of running an integrity check are as follows: Journaling on ECP-based shared-disk clustered systems in Caché (see the “ Cluster Journaling” chapter).Īn integrity check lets you verify the structural integrity (see Fundamental Data Integrity Protection) of a set of databases, or subset of globals within the databases. Journaling-based logical data replication for automatic failover and disaster recovery through mirroring (see the “ Mirroring” chapter of the Caché High Availability Guide) and shadowing (see the “ Shadowing” chapter of this guide).ĭataCheck, a tool for checking the consistency of data between multiple systems when technologies such as mirroring and shadowing maintain a replicated copy of data (see the chapter “ Data Consistency on Multiple Systems”). Tools for checking the structural integrity of databases, described in Verifying Structural Integrity in this chapter.īackup mechanisms, as described in the chapter “ Backup and Restore”. To compensate for such disasters, Caché provides the following features: In that case, the integrity of the database, WIJ and journals can become compromised. Integrity Verification and Recovery MechanismsĪlthough system crashes alone cannot lead to a loss of integrity, there is always a possibility that a storage device will fail catastrophically, sustain physical damage, or be tampered with. (Other aspects of logical integrity are under the control of application code, through proper use of interlocks, transactions, and other mechanisms specific to the programming paradigm that the application employs.)Īutomatic WIJ and journal recovery are fundamental components of the InterSystems “bulletproof” database architecture that protects Caché databases from system failures. Logical integrity during a system crash is maintained by Caché journaling (see the “ Journaling” chapter) and transaction processing. Logical integrity refers to the data represented by the globals within the database, and encompasses the self-consistency of the data created by the application, its transactional integrity, and its being up-to-date with the real world. Structural integrity during a system crash is maintained by Caché write image journal (WIJ) technology, as described in the chapter “ Write Image Journaling and Recovery”, and Caché's internal algorithms. To have structural integrity, the database blocks must be self-consistent and the globals traversable. Structural database integrity, or physical integrity, refers to the contents of the database blocks on disk. In general, there are two different levels at which integrity can be viewed: The integrity of the Caché database is protected from system failure by the features described in this guide.
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