Databases

Question 1

Relational Database Types

Answer 1

SQL
Oracle

MySQL

PostgreSQL
Aurora
MariaDB

Question 2

Non-relational databases on AWS

Answer 2

DynamoDB

Question 3

DynamoDB Database Parts

Answer 3

Collection = table
Document = Row
KV pairs = Field/data

Question 4

OLTP SF

Answer 4

Online Transaction Processing

Question 5

OLAP SF

Answer 5

Online Analytics Processing

Question 6

OLTP is

Answer 6

Pulling up data, a basic request

Question 7

OLAP

Answer 7

Analysis of a large volume of information on a database, it can use a lot of resources. Usually you̥ll use a copy

Question 8

Elasticache is

Answer 8

A deployed in-memory cache in the cloud. It caches the most consistently queries fields to make the database faster.

Question 9

DMS SF

Answer 9

Database Migration Services

Question 10

DMS

Answer 10

Allows migrations to databases and does transformation, compression and parallel transfers and converts to formats of target database

Question 11

RDS OLTP Types

Answer 11

SQL
MySQL
PostgreSQL
Oracle
Aurora
MariaDB

Question 12

OLAP Types

Answer 12

Redshift

Question 13

NoSQL DB types

Answer 13

DynamoDB

Question 14

Elasticache Types

Answer 14

Memcached
Redis

Question 15

DynamoDB is

Answer 15

Fast flexible NoSQL database for document and key-value data models

Question 16

Why use DynamoDB?

Answer 16

SSD Storage
Spread across 3 geographically distinct data centres

Question 17

Dynamo Eventual Consistent Reads

Answer 17

Default setting. Consistently copies all data within a second to other data centers. Give best read performance

Question 18

Basic inclusions of DynamoDB

Answer 18

Tables
Items (rows)
Attributes (columns)

Question 19

Levels of nesting supported in Dynamo

Answer 19

35

Question 20

Dynamo pricing for Write Throughput

Answer 20

$0.0065 per hour for every 10 units

Question 21

Dynamo pricing for read throughput

Answer 21

$0.00065 per hour for every 50 units

Question 22

Dynamo storage cost

Answer 22

first 25 GB stored per month is free
$.25 per GB per month there after

Question 23

Dynamo Strongly Consistent Reads

Answer 23

Reflects all writes that receives a successful response prior to the read

Question 24

DynamoDB the 2 types of primary keys

Answer 24

Single attribute
Composite

Question 25

DynamoDb Unique ID

Answer 25

(think unique ID) aka partition key

Question 26

DynamoDB Composite Key

Answer 26

Think unique ID and a date range Partition Key & Sort key composed of 2 attributes

Question 27

DDB Partition Key

Answer 27

Dynamo uses the partition keys value as input to an internal hash function. Must be unique!

Question 28

DDB Two items with the same partition key

Answer 28

Must have a different sort key All items of the same partition key are stored together sorted by sort key value

Question 29

DDB Local Secondary Index

Answer 29

SAME partition key, different sort key Can only be created with creating a table

Question 30

DDB Global Secondary Index

Answer 30

Has different partition and sort key Can be added at any time

Question 31

DDB Streams

Answer 31

Captures modifications - Any new items - Tracks changed items - Holds deleted items Stores for 24 hours Useful for sending an on boarding email

Question 32

DDB Query

Answer 32

Query using only primary key value. Can also use sort key (usually a date)

Question 33

Types of indexes

Answer 33

Local secondary Global secondary

Question 34

Scan vs Query

Answer 34

Query only finds by primary key value (can use sort) Scan looks at all the data and filters out (slower!)

Question 35

ProjectionExpression

Answer 35

Parameter for scanning so that the query only return some of the attributes, not all

Question 36

To get query results reverse sorted

Answer 36

Set ScanIndexForward to false

Question 37

To limit what scan shows

Answer 37

Use a projection expression

Question 38

Units of read provisioned throughput

Answer 38

Reads are rounded up to 4kb increments Consistent reads consist of 2 reads per second Strongly consistent reads are 1 read per second

Question 39

Unit of write provisioned throughput

Answer 39

All writes are 1 Kb All write consist of 1 Kb per second

Question 40

read throughput calculation

Answer 40

(Size of read rounded to nearest 4kb chunk/4) * no of items

Question 41

eventually consistent read throughput calculation

Answer 41

(Size of read rounded to nearest 4kb chunk/4) * no of items Then divide by 2

Question 42

You have an application that requires to read 10 items of 1 kb per second using eventual consistency. What should you set the read throughput to?

Answer 42

(1kb*4/4) = 1 read unit per item 1*10 = 10 10/2 = 5 units of read throughput

Question 43

What happens if consistency exceeded?

Answer 43

get a 400 code

Question 44

Web identity provider basics

Answer 44

Use Facebook/google or any open-id connect compatible to Id provider. Done with AssumeRoleWithWebIdentity API Need to create role first

Question 45

Parts of a Web Identity Provider link

Answer 45

Web identity token App ID of provider ARN of role

Question 46

Temporary security credentials include

Answer 46

Access token/key Expiration time limit AssumeRoleId SubjectFromWebIdentityToken

Question 47

Steps taken to authenticate

Answer 47

User authenticate with ID provider Passed a token by ID provider Your code calls AssumeRoleWithWebIdentity API to provide token for the ARN of the role

Question 48

You have a motion sensor which writes 600 items of data every minute. Each item consists of 5kb. What should you set the write throughput to?

Answer 48

50 Correct. 600 / 60 = 10 items per second. You are using 5kb per write and writes are measured in 1kb per write. This means that you need 5 writes per item, 5 x 10 = 50 writes per second.

Question 49

What is the API call to retrieve multiple items from a DynamoDB table?

Answer 49

BatchGetItem

Question 50

You have a motion sensor which writes 600 items of data every minute. Each item consists of 5kb. Your application uses strongly consistent reads. What should you set the read throughput to?

Answer 50

20 Correct! 600 / 60 = 10 items per second. 5kb rounded to nearest 4kb chunk is 8kb. 8 / 4 = 2. This means you need 2 reads per item. 2 x 10 = 20 reads per second. As the reads are Strongly consistent, you do not need to divide by 2. So the answer is 20.

Question 51

You have an application that needs to read 25 items of 13kb in size per second. Your application uses eventually consistent reads. What should you set the read throughput to?

Answer 51

50 Correct. Your application reads 13kb per item. Round up to the nearest 4kb chunk = 16kb. 16kb / 4kb = 4 reads per item. You have 25 items so 25 x 4 = 100. Your application requires eventually consistent reads which means you divide by 2. 100/2 = 50.

Question 52

What amazon service can you use in conjunction with SQS to fan out" SQS messages to multiple queues."

Answer 52

SNS