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3.8 KiB
3.8 KiB
DynamoDB Read/Write Units — Numeric Practice, Set 3
20 questions. Give a numeric answer for each, using 1 = <number>, 2 = <number>, and so on.
Assumptions
- Assume provisioned capacity and steady workloads.
- All item sizes are exact DynamoDB item sizes, including attribute names and values.
- Each read accesses an individual item, not a Query or Scan. Transactional operations count individual items, not transaction API calls.
- Normal writes are non-transactional. All writes create new items.
- Ignore indexes, replication, retries, failed requests, burst capacity and partition limits.
- Questions 1–14 ask for exact throughput requirements: fractional RCU answers are valid; do not round the final result to a whole number.
- Questions 15–18 ask for the maximum number of individual item operations per second.
- Questions 19–20 ask for whole-number provisioned capacity settings.
Questions
1. You normally write six separate 1.8 KB items every second. How many WCUs are required?
Answer: ______
2. You normally write nine separate 0.7 KB items every second. How many WCUs are required?
Answer: ______
3. You normally write four separate 3.01 KB items every second. How many WCUs are required?
Answer: ______
4. You transactionally write three separate 2.01 KB items every second. How many WCUs are required?
Answer: ______
5. You transactionally write six separate 1 KB items every second. How many WCUs are required?
Answer: ______
6. You perform strongly consistent reads of five separate 5 KB items every second. How many RCUs of throughput are required?
Answer: ______
7. You perform strongly consistent reads of three separate 12 KB items every second. How many RCUs of throughput are required?
Answer: ______
8. You perform eventually consistent reads of nine separate 0.8 KB items every second. How many RCUs of throughput are required?
Answer: ______
9. You perform eventually consistent reads of five separate 8.01 KB items every second. How many RCUs of throughput are required?
Answer: ______
10. You perform eventually consistent reads of seven separate 8 KB items every second. How many RCUs of throughput are required?
Answer: ______
11. You transactionally read five separate 4.01 KB items every second. How many RCUs of throughput are required?
Answer: ______
12. You transactionally read three separate 11 KB items every second. How many RCUs of throughput are required?
Answer: ______
13. Each second, you normally write two 0.6 KB items and three 2.4 KB items to the same table. How many WCUs are required in total?
Answer: ______
14. Each second, you perform strongly consistent reads of two 5 KB items and eventually consistent reads of three 1 KB items from the same table. How many RCUs of throughput are required in total?
Answer: ______
15. You have 28 WCUs available. What is the maximum number of normal item writes per second you can sustain if each item is 3.2 KB?
Answer: ______
16. You have 30 WCUs available. What is the maximum number of transactional item writes per second you can sustain if each item is 2.2 KB?
Answer: ______
17. You have 15 RCUs available. What is the maximum number of eventually consistent item reads per second you can sustain if each item is 9 KB?
Answer: ______
18. You have 32 RCUs available. What is the maximum number of transactional item reads per second you can sustain if each item is 5 KB?
Answer: ______
19. You perform eventually consistent reads of eleven separate 3 KB items every second. What is the minimum WHOLE NUMBER of RCUs you must provision?
Answer: ______
20. You perform eventually consistent reads of five separate 12.01 KB items every second. What is the minimum WHOLE NUMBER of RCUs you must provision?
Answer: ______