If the transaction consumes the disk, it could cause the
database to fail. Is there anyone who hasn??™t had this happen at one time or another?
Full Recovery mode offers no automated maintenance of the transaction log. It continues
to grow, as shown in Figure 2-2. The only way to clear it is to either switch to
Simple Recovery or back up the transaction log.
Figure 2-2. Transaction log behavior in Full Recovery mode: a recipe for disaster if the
transaction log is not maintained
Simple Recovery
The oft-maligned Simple Recovery mode clears the active transaction log of committed
transactions during a checkpoint, as shown in Figure 2-3. The advantage is that the transaction
log maintains itself and needs no direct management. The drawback is that in the
event of a disaster, you??™re guaranteed some level of data loss; it is impossible to restore to
the exact moment of failure.
CHAPTER 2 n MAKING DATABASE BACKUPS 17
Figure 2-3. In Simple Recovery, the transaction log is more or less self-maintaining.
Even though Simple Recovery mode truncates the transaction log periodically, this
doesn??™t mean that the transaction log won??™t grow.
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