On-demand vs provisioned cost comparison in DynamoDB - Visual Side-by-Side Comparison

Concept Flow - On-demand vs provisioned cost comparison

Start

↓

Choose Workload Type

↓

On-demand Pricing

↓

Calculate Cost

↓

Compare Costs

↓

Decision: Which is cheaper?

↓

End

This flow shows how to compare costs by choosing workload type, calculating costs for on-demand and provisioned modes, then deciding which is cheaper.

Execution Sample

DynamoDB

SELECT workload_type, cost
FROM dynamodb_costs
WHERE workload_type IN ('on-demand', 'provisioned')
ORDER BY cost ASC;

This query retrieves and orders DynamoDB costs for on-demand and provisioned workloads to compare them.

Execution Table

Step	Workload Type	Read Capacity Units (RCU)	Write Capacity Units (WCU)	Requests per second	Cost Calculation	Cost Result
1	On-demand	N/A	N/A	1000	Cost = 1.8M req/hr * $0.25/M (read) + 1.8M req/hr * $1.25/M (write)	$2.70
2	Provisioned	500	500	1000	Cost = (RCU * $0.00013) + (WCU * $0.00065)	$0.39
3	Compare	-	-	-	Provisioned cheaper than On-demand	Choose Provisioned
4	End	-	-	-	Comparison complete	-

💡 Comparison ends after calculating and comparing both costs.

Variable Tracker

Variable	Start	After Step 1	After Step 2	After Step 3	Final
Workload Type	None	On-demand	Provisioned	Provisioned	Provisioned
Cost	0	$2.70	$0.39	$0.39	$0.39

Key Moments - 2 Insights

Why does On-demand cost more even with the same request rate?

On-demand charges per request without reserved capacity, so costs scale directly with usage (see execution_table row 1). Provisioned reserves capacity at a lower unit price (row 2).

What happens if request rate is lower than provisioned capacity?

Provisioned cost stays the same regardless of usage, so if requests are low, you pay for unused capacity (not shown in table but implied by provisioned pricing).

Visual Quiz - 3 Questions

Look at the execution_table, what is the cost result for On-demand pricing at step 1?

A $0.39

B $2.70

C $0.75

D $1.50

💡 Hint

Check the 'Cost Result' column in row 1 of execution_table.

At which step does the comparison decide which pricing is cheaper?

A Step 1

B Step 2

C Step 3

D Step 4

💡 Hint

Look for the row where costs are compared and a choice is made (execution_table row 3).

If the request rate doubles, which cost is likely to increase more?

A On-demand cost

B Provisioned cost

C Both increase equally

D Neither increases

💡 Hint

On-demand cost scales with requests (see execution_table row 1), provisioned cost is fixed by capacity.

Concept Snapshot

On-demand pricing charges per request, good for unpredictable workloads.
Provisioned pricing reserves capacity, cheaper for steady workloads.
Calculate costs by multiplying usage by unit prices.
Compare costs to choose the best option.
Provisioned cost is fixed; On-demand scales with usage.

Full Transcript

This visual execution compares DynamoDB On-demand and Provisioned pricing. First, we select the workload type. On-demand pricing charges per request, so cost scales with usage. Provisioned pricing reserves capacity at a fixed cost. We calculate costs for both using example rates: 1000 requests per second. On-demand cost is $2.70, provisioned cost is $0.39. Comparing costs shows provisioned is cheaper for steady high usage. Key points: On-demand is flexible but can be costly at scale; provisioned is cost-effective for predictable workloads. This helps decide which pricing model to use.