Ex:Try out capacity modes

Hands-on Exercise

This exercise is carried out in AWS cloud as a result it may cost you money. To minimize the cost make sure to delete the table at the end of this exercise.

Pre-requisites

  1. AWS Account
  2. AWS CLI setup for connecting AWS cloud
  3. Permissions to run DynamoDB operations
  4. Permissions to access the console

1. Run python code to create a table

  • Python is code available in the subfolder Python
    • python/create-table-provisioned.py
    • Review the code
  • Code takes 3 arguments TABLE-Name, RCU, WCU
  • Command below will create a table with provisioned capacity of RCU=1, WCU=1
python python/create-table-provisioned.py  my-table  1 1
  • Wait for table to get created. It may take a minute or so.
aws dynamodb list-tables

2. Populate table with random item data

  • Use the Python code
    • python/generate-random-items.py
    • Review the code
  • Run the code to generate 10K items

This will result in error !! Can you guess why?

python  python/generate-random-items.py  my-table

3. Change the capacity mode for the table & try again

  • You may change it in AWS Management Console
  • OR you may use the command below to change the mode
aws dynamodb update-table --table-name my-table \
    --billing-mode   PAY_PER_REQUEST
  • Confirm billing mode is changed
aws dynamodb describe-table --table-name my-table

4. Populate table with random item data

  • Use the Python code
    • python/generate-random-items.py
    • Review the code
  • Run the code to generate 10K items

This time there will be NO error !! Can you guess why?

python  python/generate-random-items.py  my-table

5. Delete the table

aws dynamodb delete-table  --table-name my-table

6. (Optional) Checkout the metrics in Cloudwatch

  • CloudWatch captures DynamoDB table metrics
  • In this graph you see the metrics WriteThrottleEvents that occured due to the low provisioned capacity
  • The other metrics is the ConsumedWriteCapacity

throttling-graph