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DBMS Database Buffer MCQs: This section contains multiple-choice questions and answers on Database Buffer in DBMS.
Submitted by Anushree Goswami, on May 06, 2022
1. Users can directly store data in the ____ memory without accessing the disk, and they will not need to access the disk.
- Main
- Primary
- Secondary
- Tertiary
Answer: A) Main
Explanation:
Users can directly store data in the main memory without accessing the disk, and they will not need to access the disk.
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2. Keeping so many blocks in the ___ memory is difficult; we have to allocate storage space in the main memory for the blocks we need to keep.
- Primary
- Secondary
- Tertiary
- None
Answer: D) None
Explanation:
Keeping so many blocks in the main memory is difficult; we have to allocate storage space in the main memory for the blocks we need to keep.
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3. There is a database ____ in the main memory that is used for temporary storage.
- Buffer
- Set
- Storage
- None
Answer: A) Buffer
Explanation:
There is a database buffer in the main memory that is used for temporary storage.
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4. Database buffers contain copies of disk ___.
- Blocks
- Space
- Buffer
- None
Answer: A) Blocks
Explanation:
Database buffers contain copies of disk blocks.
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5. There is a possibility that the buffer version is ___ than the block copies on disk.
- Older
- Newer
- Both A and B
- None of the above
Answer: A) Older
Explanation:
There is a possibility that the buffer version is older than the block copies on disk.
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6. In order to store data into a buffer, a Buffer Manager allocates space to the buffer.
- Space
- Time
- Life
- None
Answer: A) Space
Explanation:
In order to store data into a buffer, a Buffer Manager allocates space to the buffer.
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7. When a user requests a particular block, the buffer manager provides the block address in the main memory if the block is in the buffer.
- Main memory
- Primary memory
- Secondary memory
- Tertiary memory
Answer: A) Main memory
Explanation:
When a user requests a particular block, the buffer manager provides the block address in the main memory if the block is in the buffer.
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8. The buffer manager allocates the ___ to the buffer if the ___ is not available in the buffer.
- Block
- Buffer
- Manager
- None
Answer: A) Block
Explanation:
The buffer manager allocates the block to the buffer if the block is not available in the buffer.
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9. When free space isn't available, the new block is allocated space from existing blocks thrown out from the buffer.
- Free space
- Fixed space
- Filled space
- No space
Answer: A) Free space
Explanation:
When free space isn't available, the new block is allocated space from existing blocks thrown out from the buffer.
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10. Disk writes only the ___ that have been modified recently to the disk when throwing ___ back.
- Blocks
- Buffers
- Brand
- None
Answer: A) Blocks
Explanation:
Disk writes only the blocks that have been modified recently to the disk when throwing blocks back.
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11. In such cases, the ___ manager reads the requested block from the disk into the ___, passes it to the user in main memory, and then throws out the block that the user requested.
- Block
- Database
- Buffer
- None
Answer: C) Buffer
Explanation:
In such cases, the buffer manager reads the requested block from the disk into the buffer, passes it to the user in main memory, and then throws out the block that the user requested.
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12. Programs are not aware of what the ___ manager is doing internally, which could cause a problem in disk block requests.
- Buffer
- Block
- Bid
- None
Answer: A) Buffer
Explanation:
Programs are not aware of what the buffer manager is doing internally, which could cause a problem in disk block requests.
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13. Buffer managers are similar to ____ machines.
- Real
- Virtual
- Both A and B
- None of the above
Answer: B) Virtual
Explanation:
Buffer managers are similar to virtual machines.
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14. Before allocating the new block, the existing block must be removed from the buffer if there is ___ space left.
- Some
- No
- Big
- Small
Answer: B) No
Explanation:
Before allocating the new block, the existing block must be removed from the buffer if there is no space left.
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15. By ___, a block whose least recent use has been removed from the buffer and written to the disk.
- LUR
- LRU
- RUL
- RLU
Answer: B) LRU
Explanation:
By LRU, a block whose least recent use has been removed from the buffer and written to the disk.
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16. The user should restrict the time a block can be written back to the disk so that the database system can be ___ after a crash.
- Reintroduced
- Recovered
- Reinstalled
- Reiterated
Answer: B) Recovered
Explanation:
The user should restrict the time a block can be written back to the disk so that the database system can be recovered after a crash.
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17. It is common for recovery systems not to allow writing of blocks to the disk during block ___ operations.
- Update
- Add
- Remove
- None
Answer: A) Update
Explanation:
It is common for recovery systems not to allow writing of blocks to the disk during block update operations.
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18. Known as ___ blocks, these are blocks that can't be written to the disk.
- Pinup
- Pindown
- Pinned
- Piled
Answer: C) Pinned
Explanation:
Known as pinned blocks, these are blocks that can't be written to the disk.
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19. It may be necessary to write the buffered block back to the disk in some cases, even though the buffered space is not required. Such forced output is known as forced ___ of a block.
- Input
- Output
- Buffer
- None
Answer: B) Output
Explanation:
It may be necessary to write the buffered block back to the disk in some cases, even though the buffered space is not required. Such forced output is known as forced output of a block.
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20. It is possible to lose data stored on the buffer due to a ___ of the system, but the data on the disk is not usually affected.
- Crash
- Crack
- Crux
- None
Answer: A) Crash
Explanation:
It is possible to lose data stored on the buffer due to a crash of the system, but the data on the disk is not usually affected.
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