Why do users report a performance decline in 8.0?

[Bin Wang]

Many users claim that the performance of 8.0 has declined, but this is a misconception, often based on simple sysbench test results. Users should test our open-source version in real-world environments or use better tools like BenchmarkSQL TPCC to evaluate the optimized performance, ideally testing in a clustered environment.

The feedback on performance decline mostly comes from tests on low-end machines. The reason for the performance decline in these environments is that the official version uses a new redo log mechanism, which employs a batch activation approach. This mechanism is more efficient in high-concurrency scenarios, but compared to the previous user thread self-activation mechanism, it offers no advantage in low-concurrency situations. Overall, in cases with low concurrency, the response speed has decreased, but overall efficiency has improved. However, this new mechanism greatly improves concurrent write capabilities, allowing 8.0 to outperform version 5.7 significantly in high-concurrency scenarios.