07 - Managed NoSQL: DynamoDB

Question 1

Define

Cloud Computing

Answer 1

on-demand delivery of IT resources and applications via the Internet, with pay-as-you-go pricing.

Question 2

How does cloud computing reduce IT costs?

Answer 2

1. Multiple pricing options also help you optimize costs based on your unique workloads.
   2.lower cycles In comparison, an on-premises solution typically requires upgrades on 1/3/5-year cycles. The cost of labor and systems administration can be significant. ​
2. The cost savings achieved using the cloud empowers organizations to shift resources toward innovative, new projects
3. Cloud computing can move with your business. Its speed and agility makes it possible for you to respond to changing market conditions and computing requirements. ​

Question 3

In a traditional infrastructure, ____ is a challenge due to the amount of time it can take to get a server procured, delivered, and running.

Answer 3

scalability

Question 4

When Running your database in the Cloud (IaaS), which ones are handled by you?

7

Answer 4

1. App optimization
2. Scaling
3. high availability
4. Backups (DB)
5. Patches (DB software)
6. Installations (DB software)
7. operating system patches

ASHBPIO

Question 5

When Running your database in the Cloud (PaaS), which ones are handled by you?

Answer 5

App optimization

Question 6

DynamoDB characteristics

4

Answer 6

1. Fully managed
2. Virtually unlimited
3. Low latency (< 10ms)
4. Flexible schema

Question 7

Define

flexible schema

Answer 7

• DynamoDB supports both key-value and document data models
• each row can have any number of columns at any point in time
• u can easily adapt the tables as your business requirements change
• w/o having to redefine the table schema as you would in relational databases

Question 8

When to use SQL

Answer 8

• Complex transactions/queries
• A medium to high query or write rate – Up to 30,000 IOPS (15,000 reads + 15,000 writes)
• High durability

Question 9

When to use DynamoDB

Answer 9

• Massive read/write rates (for example, 150,000 write/second)
• Sharding due to high data size or throughput demands
• Simple GET or PUT requests and queries

Can only put & read data as is

Question 10

T/F

You won’t be doing complex queries in DynamoDB and you won’t use simple GET and PUT request and queries.
You will probably would leave your analytics

Answer 10

F
You won’t be doing complex queries in DynamoDB but rather simple GET and PUT request and queries.
You will probably would leave your analytics

Aka: Can only put & read data as is

Question 11

Is DynamoDB vertically or horizontally scaled?

Answer 11

horizontally

Question 12

Define

Partition key

Answer 12

Attribute of data that divides data across multiple machines
Ex. Course

Question 13

Differentiate

Single Key vs Compound Key

Answer 13

Single key: partition key is the only key
* Partition key + attributes

Compound key
* Sort key in addition to partition key
* Partition key + sort key + attributes

Question 14

Define

Sort Key/Range Key

Answer 14

Sorts data w/in a partition

Question 15

Note that if you decide to only specify a partition key and not a sort key (also known as a Range Key), all records must have a _____________

Answer 15

unique partition key value

Question 16

As data grows, how is table partitioned?

Answer 16

Partitioned by key

Question 17

When do you use QUERY vs SCAN?

Answer 17

QUERY by key to find items efficiently
SCAN to find items by attribute

Question 18

Is SCAN cost-effective for DynamoDB?

Answer 18

No
Need to practice proper data modeling, para ma-identify primary keys & data will be more cost effective

Question 19

DynamoDB Data Modeling Process

Answer 19

1. Start with an ERD
2. Define access patterns
3. Design your table schema
4. FORGET YOUR RELATIONAL CONCEPTS

Question 20

Elaborate

FORGET YOUR RELATIONAL CONCEPTS

Answer 20

NO normalization
NO joins
NO one entity per table rule

Question 21

Differentiate

Global Secondary Index vs Local Secondary Index

Answer 21

GSI: alternate partition and/or sort key (online indexing)
* Index across all partition keys
* Has RCUs/WCUs (Read Capacity Unit / Write Capacity Unit)
* can assign a new partition key and new sort key
* gives a new primary key
* functions as a new table (redundancy of old, w/ new partition key & sort key)

LSI: alternate sort key attribute
* Index is local to a partition key, enclosed
* Doesn’t change partition key, only assigns a new sort key
* 10 GB max per partition key

Question 23

Define

Projection
What is part of a projection

Answer 23

Projection: new table
* new partition and sort key
* old partition key
* extra attributes, or all attributes

Question 24

How to choose a good partition key?

Answer 24

• Match common access patterns
• High cardinality
• Evenly distributed values
• Is well-known to the application