Database Performance Analysis 2025: PostgreSQL 17 vs MySQL 8.4 LTS vs MariaDB 11.8 LTS

Executive Summary

Storage speed determines database performance more than feature comparisons. MariaDB dominates on slow storage (1.8x faster than PostgreSQL), PostgreSQL excels at analytics (13x faster than MariaDB), MySQL provides the most operational stability for web applications.

Critical Performance Thresholds

Storage Impact on Database Choice

• Slow storage (≤125 MiB/s): MariaDB 1.8x faster than PostgreSQL
• Fast NVMe storage: PostgreSQL lead reduces to 1.2x over MariaDB
• OLAP workloads: PostgreSQL 13x faster than MariaDB
• OLTP workloads: MySQL excels for simple queries, PostgreSQL for complex queries

Breaking Points by Database

• PostgreSQL UI failure: 1000 spans makes debugging distributed transactions impossible
• MySQL query cache: Entire cache invalidated on single row update
• MariaDB thread pool: Deadlocks occur above 500 concurrent connections

Production Configuration Requirements

PostgreSQL 17 Critical Settings

autovacuum_max_workers = 6                    # Prevents VACUUM backlog disasters
autovacuum_vacuum_scale_factor = 0.1          # VACUUM when 10% changes
max_wal_size = 4GB                           # Prevents checkpoint storms
shared_buffers = 8GB                         # 25% of system RAM
random_page_cost = 1.1                       # SSD optimization (default 4.0 fails)

MySQL 8.4 LTS Production Settings

innodb_buffer_pool_size = 16G               # 70% of RAM
innodb_flush_log_at_trx_commit = 2          # Performance vs durability trade-off
binlog_format = ROW                          # Prevents replication corruption
innodb_redo_log_capacity = 2G                # Default 100MB causes bottlenecks

Failure Scenarios and Costs

Migration Disasters

• PostgreSQL migration cost: $47k total (3 weeks dev time + $8k consultant fees + storage upgrades)
• MariaDB "compatibility" issues: 3 months to discover silent data corruption
• MySQL 8.4 upgrade risks: Binary log corruption in versions 8.4.0-8.4.2

Critical Error Patterns

# PostgreSQL MVCC failure
ERROR: canceling statement due to conflict with recovery
# Translation: 50GB dead rows, VACUUM can't keep up

# MySQL authentication break
ERROR 2059: Authentication plugin 'caching_sha2_password' cannot be loaded
# Translation: Legacy PHP apps fail without warning

# MariaDB replication divergence  
Last_Errno: 1666 Operation CREATE USER failed
# Translation: Galera doesn't replicate user management as expected

Decision Matrix by Use Case

Web Applications (90% of use cases)

• Choice: MySQL 8.4 LTS
• Rationale: Universal hosting support, developer availability, proven stability
• Cost reality: $200/month handles 10x traffic of equivalent PostgreSQL setup
• Risk factors: Oracle licensing audits ($50k surprise bills documented)

Analytics/Business Intelligence

• Choice: PostgreSQL 17
• Rationale: 13x faster than MariaDB on complex queries, comprehensive analytics features
• Prerequisites: Dedicated DBA or 30-second dashboard load times
• Breaking point: Requires separate data warehouse at Reddit/Instagram scale

Oracle License Avoidance

• Choice: MariaDB 11.8 LTS (with extensive testing)
• Migration time: 3-6 weeks realistic vs "2 days" developer estimates
• Hidden costs: MariaDB expertise costs 20-30% more than MySQL
• Compatibility reality: "MySQL-compatible" means 90% compatible

Storage Performance Requirements

I/O Thresholds for PostgreSQL Success

# Minimum viable PostgreSQL performance
write: IOPS=5000, BW=20.0MiB/s

# PostgreSQL failure zone (AWS gp2 volumes)
write: IOPS=800, BW=3200KiB/s
# Result: 10x query slowdown vs local SSD testing

Version-Specific Gotchas

MySQL 8.4.x Issues

• 8.4.0: innodb_log_file_size changes break upgrades (6 hours recovery time)
• 8.4.3: Binlog format bug with LOAD DATA causes silent corruption
• 8.0.34: caching_sha2_password breaks legacy PHP without warning

PostgreSQL 17.x Issues

• 17.0: Memory leak in parallel workers crashes production
• 15.0: VACUUM crashes on tables >50GB, requires pg_resetwal recovery

MariaDB 11.8.x Issues

• 11.8.0: Thread pool deadlock costs $12k downtime
• 10.6: Query optimizer differences break existing MySQL queries

Resource Requirements by Database

PostgreSQL 17

• RAM usage: Higher for complex workloads (MVCC overhead)
• Expertise required: Understanding of VACUUM, query planner, MVCC
• Support ecosystem: Multiple vendors, comprehensive tooling
• Installation size: ~200MB

MySQL 8.4 LTS

• RAM usage: Optimized for web applications
• Expertise required: Straightforward configuration, wide knowledge base
• Support ecosystem: Largest ecosystem, universal hosting
• Installation size: ~1GB

MariaDB 11.8 LTS

• RAM usage: Balanced between MySQL and PostgreSQL
• Expertise required: MySQL-compatible but different optimizer behavior
• Support ecosystem: Smaller than MySQL, growing
• Installation size: ~400MB

Operational Intelligence

What Documentation Doesn't Tell You

• PostgreSQL: Append-only storage means old row versions accumulate until VACUUM runs
• MySQL: Query cache sounds good but invalidates entire cache on single row update
• MariaDB: "MySQL-compatible" breaks on replication edge cases and optimizer differences

Real-World Performance vs Benchmarks

• Synthetic benchmarks: Test on local NVMe SSDs
• Production reality: AWS gp2 volumes at 1000 IOPS destroy PostgreSQL performance
• Storage cost impact: Proper PostgreSQL storage costs 3x more than advertised

Breaking Changes That Destroy Weekends

• MySQL 8.0.29: Silent binlog corruption loses 3 hours of transactions
• PostgreSQL major upgrades: Require pg_dump/restore, no in-place upgrades
• MariaDB Galera: User management doesn't replicate like standard MySQL

Monitoring Critical Metrics

PostgreSQL Health Indicators

• Dead tuple ratio: >20% indicates VACUUM problems
• Cache hit ratio: <95% means insufficient shared_buffers
• WAL generation rate: Sustained >100MB/minute indicates tuning needed

MySQL Performance Signals

• InnoDB buffer pool hit rate: <99% indicates memory pressure
• Slow query log growth: >100 queries/hour at 100ms threshold
• Replication lag: >5 seconds indicates I/O or network issues

MariaDB Specific Monitoring

• Thread pool utilization: >80% indicates configuration problems
• Galera flow control: Any pauses indicate network or disk bottlenecks

Decision Framework Summary

1. Standard web application: MySQL 8.4 LTS (boring choice that works)
2. Complex analytics needs: PostgreSQL 17 (hire competent DBA)
3. Oracle license avoidance: MariaDB 11.8 LTS (test extensively)
4. Startup with "BI needs": PostgreSQL 17 (most "analytics" is glorified GROUP BY)

Critical Success Factors

• Test with actual storage speeds, not synthetic benchmarks
• Budget 3-6 weeks for any database migration, not optimistic estimates
• Hire expertise or accept 3am emergency calls
• Monitor what actually matters, not vanity metrics
• Configure properly from day one - defaults are designed for demos, not production

The database choice itself rarely kills startups. Choosing poorly and ignoring operational requirements until 3am disasters definitely will.