Amazon Web Services: Developer Associate
Exam Prep: Practice I
SQS guarantees deliver but there can be duplicates. True or False?
True
What is the maximum number of SWF domains allowed in an AWS account?
100
Company B has created an e-commerce site using DynamoDB and is designing a
products table that includes items purchased and the users who purchased the
item. When creating a primary key on a table, what would be the best attribute for
the primary key?
user_id where there are many users to few products
In DynamoDB, an atomic counter allows all write requests to be applied in the
order they are received by incrementing or decrementing the attribute value. True
or False?
True
Company B is writing 10 items to the products table every second. Each item is
15.5Kb in size. What would be the required provisioned write throughput for best
performance? Explain.
160. For write capacity, the rule is to divide the item size by 1KB. Hence we need to
divide 15.5 by 1 which gives us 16 to the nearest 1KB. Since we are writing 10 items
per second, we need to multiply 10*16= 160.
Company B is using strongly consistent reads to request 50 items per second
from their customer table. Each item is 20KB in size. What throughput would be
required to efficiently handle the read throughput of the table? Explain.
250. For read capacity, the rule is to divide the item size by 4KB. Hence we need to
divide 20 by 4 which gives us 5 to the nearest 4KB. Since we are writing 50 items per
second, we need to multiply 50*5=250.
In DynamoDB, how many tables can an AWS account have per region?
256
Which of the following is not a benefit of a query over a scan?
-Returns all attributes on an item
-It does not do consistent reads
-Much more efficient because it searches indexes only
-Returns the items matching the primary key
It does not do consistent reads
Which API call can be used to retrieve up to 100 items at a time or 1MB of data
from a DynamoDB table?
BatchGetItem
For best performance when retrieving data from a table, what "type" of API call
should you perform?
Query
What is the primary difference between a global secondary index and a local
secondary index?
, A local secondary index has the same partition key as the primary key and the global
secondary index has a different partition and sort key
For how long can a SWF workflow task or task execution can live up to?
1 year
How many secondary indexes are allowed per table?
5 local and 5 global secondary indexes are allowed which gives a maximum of 10 per
table.
You can define up to 5 local secondary indexes and 5 global secondary indexes
per table. How can you increase your DynamoDB secondary indexes limit in a
region?
DynamoDB does not allow secondary index limit increase
Company B has many users updating the same table. At times it is not
uncommon for multiple users to update the same item and attribute of an item at
the same time. If user A calls an item in a table to update an attribute at the same
time as user B and user B updates the table first, what can we deploy in
DynamoDB to ensure User A is not updating an item that was updated since User
A's table read?
Conditional Writes
When can you add a secondary index to a table?
Anytime if it is a global index
How many global secondary indexes are allowed per table?
5
Company B has a DynamoDB table where the average item size is 10KB.
Company B anticipates that the application will read 100 items from the table per
second using eventual consistent reads. How much read capacity throughput
should they provision? Explain.
For read capacity, the rule is to divide the item size by 4KB. Hence we need to divide 10
by 4 which gives us 3 to the nearest 4KB. Since we are writing 100 items per second,
we need to multiply 100*3=300. Since it is eventual consistency, we need ti divide by 2
which gives us 150.
Which of the following datatypes can be indexed in DynamoDB? Choose 3.
-String
-Number
-List
-Boolean
String, Number, and Boolean
What are the consistency models available for Local Secondary Indexes in
DynamoDB? Choose two of the following.
-Strong consistent reads
-Primary reads
-Secondary reads
-Eventual consistent reads
Strong consistent reads and Eventual consistent reads
Any local secondary index in a DynamoDB table can be updated once it is
created. True or False?
False
Exam Prep: Practice I
SQS guarantees deliver but there can be duplicates. True or False?
True
What is the maximum number of SWF domains allowed in an AWS account?
100
Company B has created an e-commerce site using DynamoDB and is designing a
products table that includes items purchased and the users who purchased the
item. When creating a primary key on a table, what would be the best attribute for
the primary key?
user_id where there are many users to few products
In DynamoDB, an atomic counter allows all write requests to be applied in the
order they are received by incrementing or decrementing the attribute value. True
or False?
True
Company B is writing 10 items to the products table every second. Each item is
15.5Kb in size. What would be the required provisioned write throughput for best
performance? Explain.
160. For write capacity, the rule is to divide the item size by 1KB. Hence we need to
divide 15.5 by 1 which gives us 16 to the nearest 1KB. Since we are writing 10 items
per second, we need to multiply 10*16= 160.
Company B is using strongly consistent reads to request 50 items per second
from their customer table. Each item is 20KB in size. What throughput would be
required to efficiently handle the read throughput of the table? Explain.
250. For read capacity, the rule is to divide the item size by 4KB. Hence we need to
divide 20 by 4 which gives us 5 to the nearest 4KB. Since we are writing 50 items per
second, we need to multiply 50*5=250.
In DynamoDB, how many tables can an AWS account have per region?
256
Which of the following is not a benefit of a query over a scan?
-Returns all attributes on an item
-It does not do consistent reads
-Much more efficient because it searches indexes only
-Returns the items matching the primary key
It does not do consistent reads
Which API call can be used to retrieve up to 100 items at a time or 1MB of data
from a DynamoDB table?
BatchGetItem
For best performance when retrieving data from a table, what "type" of API call
should you perform?
Query
What is the primary difference between a global secondary index and a local
secondary index?
, A local secondary index has the same partition key as the primary key and the global
secondary index has a different partition and sort key
For how long can a SWF workflow task or task execution can live up to?
1 year
How many secondary indexes are allowed per table?
5 local and 5 global secondary indexes are allowed which gives a maximum of 10 per
table.
You can define up to 5 local secondary indexes and 5 global secondary indexes
per table. How can you increase your DynamoDB secondary indexes limit in a
region?
DynamoDB does not allow secondary index limit increase
Company B has many users updating the same table. At times it is not
uncommon for multiple users to update the same item and attribute of an item at
the same time. If user A calls an item in a table to update an attribute at the same
time as user B and user B updates the table first, what can we deploy in
DynamoDB to ensure User A is not updating an item that was updated since User
A's table read?
Conditional Writes
When can you add a secondary index to a table?
Anytime if it is a global index
How many global secondary indexes are allowed per table?
5
Company B has a DynamoDB table where the average item size is 10KB.
Company B anticipates that the application will read 100 items from the table per
second using eventual consistent reads. How much read capacity throughput
should they provision? Explain.
For read capacity, the rule is to divide the item size by 4KB. Hence we need to divide 10
by 4 which gives us 3 to the nearest 4KB. Since we are writing 100 items per second,
we need to multiply 100*3=300. Since it is eventual consistency, we need ti divide by 2
which gives us 150.
Which of the following datatypes can be indexed in DynamoDB? Choose 3.
-String
-Number
-List
-Boolean
String, Number, and Boolean
What are the consistency models available for Local Secondary Indexes in
DynamoDB? Choose two of the following.
-Strong consistent reads
-Primary reads
-Secondary reads
-Eventual consistent reads
Strong consistent reads and Eventual consistent reads
Any local secondary index in a DynamoDB table can be updated once it is
created. True or False?
False
