Demystifying QPS, TPS, PV, UV, DAU, MAU and System Throughput

1. QPS

QPS Queries Per Second is the number of queries a server can handle per second, representing the maximum request response rate and overall throughput capacity.

2. TPS

TPS Transactions Per Second counts completed transactions per second, where a transaction is a client request and the server’s response.

3. Difference Between QPS and TPS

TPS includes the entire request‑response cycle (client request, internal server processing, server response). QPS counts every individual query to the server, which may be multiple per transaction.

For example, a page load may generate three server requests, resulting in one TPS but three QPS.

4. Concurrency

Concurrency (or concurrent users) is the number of requests the system can handle simultaneously, reflecting load capacity.

5. Throughput

Throughput is the amount of work the system processes per unit of time; both QPS and TPS are common throughput metrics.

Key Throughput Factors

Throughput depends on request CPU consumption, external interfaces, I/O, etc. Higher CPU cost per request reduces overall throughput.

Important Parameters

QPS/TPS: number of requests or transactions per second

Concurrency: simultaneous requests/transactions

Response Time: average response time

Relationship:

QPS (or TPS) = Concurrency / Average Response Time

6. PV (Page View)

PV counts each page load or refresh as a view, typically derived from daily access logs.

7. UV (Unique Visitor)

UV counts distinct users visiting within a day, deduplicated by unique identifiers.

8. DAU (Daily Active Users)

DAU measures the number of unique users who interact with a product in a single day, similar to UV.

9. MAU (Monthly Active Users)

MAU counts distinct users over a month, after deduplication.

10. System Throughput Evaluation

When designing a system, consider CPU, I/O, external service latency, and estimate performance. Besides QPS and concurrency, daily PV is another dimension for capacity planning.

Typical method: identify the system’s peak TPS and daily PV, which usually have a stable relationship (excluding holidays or seasonal effects). Use stress testing or experience to estimate peak TPS, then calculate maximum daily throughput.

11. Basic Concepts and Formulas for Software Performance Testing

From a user perspective, the critical metric is response time—the interval from an action (click, request) to the result being displayed.

From an administrator perspective, key points include response time, resource utilization (CPU, memory, I/O), scalability, maximum concurrent users, potential bottlenecks, hardware upgrades, and 24/7 availability.

From a developer perspective, consider architecture rationality, database design, code efficiency, memory usage, thread synchronization, and resource contention.