The LSN stored in a page of the database refers to an update record in the log describing the most recent update to the page. Suppose that a transaction has performed the last update to a page and later aborts. Since its update to the page is reversed, the LSN in the page no longer refers to the appropriate update record. Why is this not a problem in the description of logging in the text?
What will be an ideal response?
When the update is reversed, a compensation log record is written to the log and its LSN is recorded in the page. Since the UNDO can be viewed as simply another write, the page’s LSN is correct.
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Answer the following statements true (T) or false (F)
1. Under UNIX, you can print or display your working directory by issuing the line command dir. 2. To display the contents of a UNIX directory code a dir line command. 3. You must use a line command to create a new directory under UNIX. 4. Under UNIX, to change your working directory, issue a cd (change directory) line command. 5. In a UNIX directory listing, the single double period stands for the working directory, and the single period is a synonym for its parent.