Assess logging is when a record is kept of all attribute accesses made by a particular user. It is not directly relevent with supporting data recovery. A dump is when the whole database is stopped in a consistent state and then copied onto another storage medium (such as tape). If something later happens to the database, it can be reloaded from the second storage medium. This is the process by which locks are obtained by a transaction (locks are obtained or promoted when needed, but only released at the end of a transaction). Such an approach is desirable to maintain consistency in a database system. A checkpoint is when the database reaches a consistent state, and all transactions have either been committed or aborted. It is during this time that logs or journals can be truncated. This is the record of attribute changes made by transactions since the last checkpoint. It is useful when performing roll-backs or roll-forwards.
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