CKPTINTVL specifies the frequency, expressed in seconds, at which the database server checks to determine whether a checkpoint is needed. When a full checkpoint occurs, all pages in the shared-memory buffer pool are written to disk. When a fuzzy checkpoint occurs, nonfuzzy pages are written to disk, and the page numbers of fuzzy pages are recorded in the logical log.
If you set CKPTINTVL to an interval that is too short, the system spends too much time performing checkpoints, and the performance of other work suffers. If you set CKPTINTVL to an interval that is too long, fast recovery might take too long.
In practice, 30 seconds is the smallest interval that the database server checks. If you specify a checkpoint interval of 0, the database server does not check if the checkpoint interval has elapsed. However, the database server still performs checkpoints. Other conditions, such as the physical log becoming 75 percent full, also cause the database server to perform checkpoints.
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