Question

When these buffers are all occupied, and additional database disk blocks must be copied into ___, some ____ is used to choose which of the current buffers is to be replaced. If the chosen buffer has been modified, it must be written back to disk before it is reused.

A) main memory, replacement algorithm
B) cache, replacement algorithm
C) secondary memory, replacement algorithm
D) virtual memory, replacement algorithm

Answer 1

The buffers are copied into main memory when full, and a replacement algorithm decides which buffer to replace. If a buffer is modified, it is written back to disk before reuse. The correct answer is A) main memory, replacement algorithm.

Step-by-step explanation:

When these buffers are all occupied, and additional database disk blocks must be copied into main memory, some replacement algorithm is used to choose which of the current buffers is to be replaced. If the chosen buffer has been modified, it must be written back to disk before it is reused. The correct answer is A) main memory, replacement algorithm.

In database systems, the buffer pool is a critical component for managing the cache of disk blocks in main memory. When the buffer pool is full, the database management system uses a replacement algorithm to determine which buffer to replace. Common replacement algorithms include Least Recently Used (LRU), Most Recently Used (MRU), and First In, First Out (FIFO). The objective is to minimize the number of disk accesses, which are time-consuming operations, thus ensuring efficient database performance.