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MySQL 9.7.0 PGO Benchmark Analysis

May 22, 2026

Author

Bogdan Degtyariov

MySQL

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Overview

Servers Tested:

MySQL 9.7.0 (PGO-enabled build released by Oracle)
MySQL 9.7.0 Non-PGO (built without Profile-Guided Optimization — see BUILD.md)

Tier Configurations:

Tier 2G: 2GB InnoDB buffer pool
Tier 12G: 12GB InnoDB buffer pool
Tier 32G: 32GB InnoDB buffer pool

View Results

📊 Interactive Reports

The benchmark reports are available as interactive HTML pages at:

https://percona-lab-results.github.io/2026-pgo/index.html

Performance Graphs

Tier 2G (2GB Buffer Pool):

Tier 12G (12GB Buffer Pool):

Tier 32G (32GB Buffer Pool):

Key Findings

Performance Impact of PGO

MySQL 9.7.0 with Profile-Guided Optimization (PGO) demonstrates measurable performance improvements over the non-PGO build:

Overall Performance Summary:

Average improvement: 6.5% across all configurations
Peak improvement: 14.3% (Tier 32G, 1 thread), gradually tapering to 10.3% at 512 threads as concurrency increases
Performance gains range from 0.5% to 14.3% in most scenarios
Minor regression (-3.1% at Tier 12G, 128 threads)

Performance by Buffer Pool Size:

Tier 2G (2GB buffer pool): Average improvement of 3.0%

– Best gains at 4 threads (5.5% improvement)

– Gains range from 0.5% to 5.5% across all thread counts

– Modest improvements with no regressions

Tier 12G (12GB buffer pool): Average improvement of 4.1%

– Best gains at 4 threads (8.6% improvement)

– Strong gains at low concurrency (1-4 threads: 7.3%-8.6%)

– Minor regression at 128 threads (-3.1%), neutral at 512 threads (-0.0%)

Tier 32G (32GB buffer pool): Average improvement of 12.2%

– Consistently strong gains across all thread counts (10.3% to 14.3%)

– Peak performance at lowest concurrency (1 thread: 14.3%)

– Maintains 11-12% improvement even at highest concurrency (128-512 threads)

Key Observations:

PGO provides the most significant benefits with larger buffer pools (32GB tier shows 12.2% average improvement)
Largest buffer pool configuration benefits from PGO across all concurrency levels with no regressions
Low to moderate concurrency (1-32 threads) shows best PGO gains across all tiers
Smaller buffer pools (2GB, 12GB) show more modest improvements and occasional regressions at very high thread counts
The performance improvements demonstrate PGO’s effectiveness in optimizing hot code paths, particularly when memory resources are abundant

InnoDB Metrics Analysis

Deep analysis of InnoDB metrics reveals the source of PGO’s performance improvements:

Root Cause: CPU-Level Optimizations

PGO improvements are NOT from I/O optimization, caching, or lock reduction
Buffer pool hit ratios remain virtually identical between PGO and non-PGO builds
Lock contention is minimal in both builds
All I/O metrics scale proportionally with increased throughput

What PGO Actually Optimizes:

✓ Better instruction cache utilization
✓ Improved branch prediction in hot code paths
✓ Optimized function inlining
✓ More efficient CPU instruction ordering

The metrics confirm that PGO’s 6.5% average improvement comes entirely from making the CPU more efficient at executing MySQL’s hot code paths, allowing it to process more transactions per second with the same hardware resources.

What is PGO?

Profile-Guided Optimization (PGO) is a compiler optimization technique that uses runtime profiling data to guide code optimization. The compiler first instruments the code, collects execution profiles during typical workload runs, and then recompiles the code with optimizations targeted at the most frequently executed code paths.

Benefits of PGO: