02 Distributed Storage

Question 1

What is fragmentation?

Answer 1

Splitting data intro fragments to distribute them to different nodes

Question 2

What is replication?

Answer 2

Put same data fragment on multiple nodes

Question 3

Horizontal Fragmenation

Answer 3

Split data by rows

Question 4

Vertical fragmentation

Answer 4

Split data by columns

Question 5

Shared Data Advantages (2)

Answer 5

• Load Balancing
• Fault-tolerant

Question 6

Shared Data Disadvantages

Answer 6

High Latency

Question 7

Shared-nothing advantages (2)

Answer 7

• Low latency
• simple to implement

Question 8

Shared-nothing disadvantage

Answer 8

Prone to load imbalance and node failures

Question 9

What is allocation of data?

Answer 9

Decide on which server to put fragment

Question 10

3 Fragmentation Schemes

Answer 10

• Round-Robin
• Range partitioning
• Hash-Partitioning

Question 11

What is co-partitioned data?

Answer 11

Same partitioning function used for both tables

Question 12

What is pruning of partitions?

Answer 12

• skip unnecessary partitions during query execution

Question 13

What is data-distribution skew?

Answer 13

Some nodes have more data than others