aws dynamodb provisioned throughput

DynamoDB provisioned throughput is measured in "capacity units".

During table creation you can specify requirements in terms of "read" and "write" capacity units.

Write capacity units

1x write capacity unit = 1x 1KB write per second

Read capacity units

1x read capacity unit = 1x strongly consistent read of 4KB per second OR 2x eventually consistent reads of 4KB per second (default)

Example: Your app needs strongly consistent reads at a rate of 80 reads/s and it has a payload of 3KB per read.

You'll provision:

• size of each payload / 4KB
  • 3KB/4KB = 0.75
• Rounded-up to the nearest whole number, each read operation needs 1x read capacity unit
• Multiply the number of reads per second = 80 read capacity units required

for strongly consistent reads

Exam tips

• Write capacity units - 1x 1KB write per second
• Read capacity units (strongly consistent) - 1x 4KB write per second
• Read capacity units (eventually consistent) - 2x 4KB write per second