DynamoDB

Question 1

What is Dynamo DB?

Answer 1

No Sql Database in AWS

Question 2

What does Dynamo offers for CRUD operations?

Answer 2

PutItem, GetItem, UpdateItem and DeleteItem

PI, GI, UI and DI

Question 3

What are the Batch Operation does Dynamo offers?

Answer 3

BatchGetItem and BatchWriteItem (BGI and BWI. These are parallel operations)

Question 4

maximum item size in DynamoDB is _____

Answer 4

400KB

Question 5

A single BatchGetItem operation can retrieve a maximum of ___ items and can not exceed ___ in size.

Answer 5

100 and 16MB

Question 6

A single BatchWriteItem operation can write a maximum of ___ items and can not exceed ___ in size.

Answer 6

25 and 16MB

Question 7

You don’t need to specify full primary key value to read an item if its a composite primary key in dynamo?

Answer 7

False

Question 8

Dynamo DB uses ______ consistent reads by default?

Answer 8

eventually

Question 9

Dynamo Batch request does not fail unless all the requests in the batch fails?

Answer 9

True

Question 10

Can two items in a table have same partition key value?

Answer 10

No. If so, you have to use sort key as well

Question 11

You can modify the local secondary index in dynamo?

Answer 11

No, they gets created during the table creation and can’t be changed.

Question 12

You can modify the Global secondary index in dynamo?

Answer 12

Yes, we can

Question 13

What index is same partition key + different sort key in dynamo?

Answer 13

Local Secondary Index

Question 14

What index is different partition key + different sort key in dynamo?

Answer 14

Global Secondary Index

Question 15

Dynamo Primary Key Concept?

Answer 15

• • Single Attribute (Unique ID)
• —> Partition Key (Hash key) of one attribute
• • Composite Key (Unique + Date Range)
• —>Partition & Sort Key (Hash and Range) of two attributes

Question 16

Does a Local secondary index shares provisioned throughput settings for read and write activity with the table it is indexing.

Answer 16

True

Question 17

Max dynamo db tables per Region per account

Answer 17

256

Question 18

Max default Local and Global Secondary Index

Answer 18

5 and 20 (Total 25)

Question 19

Can you request AWS to increase Local Secondary Index more than 5?

Answer 19

No, max is 5 for LSI

Question 20

Can you request AWS to increase Global Secondary Index more than 20?

Answer 20

Yes, you need to contact AWS support

Question 21

Max Size of an item Collection in dynamo db is

Answer 21

10GB

Question 22

Dynamo Accelerator

Answer 22

is used to increase the performance for read heavy workloads.

Question 23

Do you suggest to use Dynamo DAX for write heavy applications?

Answer 23

No.
DAX is not meant for
-- Strongly Consistent reads
-- Write Intense apps
-- Apps with few reads
-- Apps does not need micro second responses

Question 24

Strongly Consistent Read Capacity Formula

Answer 24

(ITEM SIZE (rounded up to the next 4KB multiplier) / 4KB) * # of items

Question 25

Write Capacity Formula

Answer 25

(ITEM SIZE (rounded up to the next 1KB multiplier) / 1KB) * # of items

Question 26

We have an item size of 3 KB and we want to read 80 (strongly consistent read) items per second per table. What is the read capacity required?

Answer 26

The formula to determine the total number of read operations is the ITEM SIZE (rounded up to the next multiple of 4 KB, since, again, we can’t group multiple items together) / 4 KB. In this example, we take 3, round it up to 4, and divide it by 4, which gives us 1 read capacity. However, we want to read 80 of these 3 KB items at the same time, so we need to multiply our result by 80, and we end up with 80 for our read throughput capacity.

So:

80 * (3KB (round up to 4) / 4KB)
80 * 1 = 80 required provisioned read throughput

Question 27

Eventual Consistent Read Capacity Formula

Answer 27

((ITEM SIZE (rounded up to the next 4KB multiplier) / 4KB) * # of items)/2

OR
Strongly Consistent Read Capacity Formula / 2

Question 28

We need 10 writes per second, and we have an item of size 1.5KB, how much throughput is required?

Answer 28

Let’s take our item size of 1.5 KB, and round it up to 2KB, then divide that by 1KB. We take that result, which is 2, and we multiply it by the number of items of that size we want to write per second. In this case, that’s 2 times 10, which gives us 20 write capacity units.

SO,

•(ITEM SIZE (1.5KB) / 1 KB) x 10 = 20 capacity units
This is even simpler than reads, because we don’t have to worry about eventually consistent or strongly consistent.

Question 29

What is the use of TTL in Dynamo?

Answer 29

To delete the expired data automatically

Question 30

When does the records be deleted after marking to be deleted in Dynamo?

Answer 30

24-48 hours

Question 31

Dynamo data supporting formats?

Answer 31

JSON, XML and HTML