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Multiple choice a) Which of the following about in-memory databases are true? If

ID: 3589532 • Letter: M

Question

Multiple choice

a) Which of the following about in-memory databases are true?

If the machine running the in-memory database restarts, all the data is lost

Fetching data from memory (RAM) is orders of magnitude faster than fetching data from the disk

In-memory databases need to have a predetermined schema

In-memory databases can never store data on the disk

b) Multiple choice

Which of the following statements about MongoDB are false? Mark all that apply.

All MongoDB documents should have the same set of fields

MongoDB is a wide column database

MongoDB supports JSON documents

Adding a field to a document will add that field to all documents

c)

Which of the following assumptions should not be made about a distributed system? Mark all that apply.

The network latency is always low and predictable

The set of computer working together (called group of nodes) can change over time

New nodes cannot join a distributed system

The nodes of a distributed system may fail at any time

If the machine running the in-memory database restarts, all the data is lost

Fetching data from memory (RAM) is orders of magnitude faster than fetching data from the disk

In-memory databases need to have a predetermined schema

In-memory databases can never store data on the disk

b) Multiple choice

Which of the following statements about MongoDB are false? Mark all that apply.

1

All MongoDB documents should have the same set of fields

2

MongoDB is a wide column database

3

MongoDB supports JSON documents

4

Adding a field to a document will add that field to all documents

c)

Which of the following assumptions should not be made about a distributed system? Mark all that apply.

The network latency is always low and predictable

The set of computer working together (called group of nodes) can change over time

New nodes cannot join a distributed system

The nodes of a distributed system may fail at any time

Explanation / Answer

a)

If the machine running the in-memory database restarts, all the data is lost
Fetching data from memory (RAM) is orders of magnitude faster than fetching data from the disk


b)

MongoDB is a wide column database
Adding a field to a document will add that field to all documents


c)

The network latency is always low and predictable
The nodes of a distributed system may fail at any time