ProxySQL 3.0.3 and 3.0.4: A Smoother Day-to-Day for PostgreSQL and MySQL Operators
We shipped ProxySQL 3.0.3 and 3.0.4 close together, and while the release notes are detailed, the real story is simpler: day-to-day operation got smoother. PostgreSQL compatibility matured in important ways, MySQL edge cases became far less disruptive, monitoring got more trustworthy, and the configuration path got safer.
If you’re running ProxySQL in production, these two releases are about fewer surprises and more confidence—especially if you’re bringing PostgreSQL traffic into ProxySQL for the first time.
PostgreSQL: Fewer “Driver Weirdness” Moments, More Predictability
The biggest shift in 3.0.3 is support for PostgreSQL’s Extended Query Protocol. That’s the protocol most real applications use when they rely on prepared statements or richer client behavior.
What you feel as an operator: fewer client-specific incompatibilities, cleaner session behavior under load, and better visibility into prepared statement usage.
Then 3.0.4 polished the PostgreSQL experience further with a PostgreSQL-aware query tokenizer. That means more accurate query digests: similar queries are grouped correctly, analysis and caching behave more predictably, and visibility tools tell a clearer story.
MySQL: Better Behavior Around the Edges
For MySQL users, 3.0.4 focused on the things that cause unexplained hiccups in production:
Unexpected COM_PING packets are handled safely. Some clients ping mid-query; those pings now get queued and answered cleanly without interrupting the active query.
SELECT @@version no longer hits your backend. ProxySQL answers these directly, cutting out unnecessary backend connections and noise.
Client timeouts now behave like clients expect. Client-specified wait_timeout values are honored (safely clamped to global settings), reducing confusion when clients manage their own timeouts.
Monitoring: More Honest Numbers, Better Signals
Monitoring is only useful if you trust it, and a few fixes landed to make that true:
Ping latency is now more accurate. The monitor’s ping scheduling was over-reporting latency in some cases; that’s been corrected.
TCP keepalive warnings surface early. If keepalive is disabled, ProxySQL now tells you, helping prevent slow-burn connection problems.
Safety and Stability: Quiet Improvements That Matter
Some of the most important changes are the ones you don’t notice—until they’re missing.
Configuration parsing is hardened against SQL injection. This is a concrete safety improvement, especially in templated or generated configuration environments.
Session teardown and processlist handling are safer. That means fewer crashes and fewer edge cases when connections are dropped or restarted under pressure.
Replication and prepared-statement hot paths are faster. Less contention under load means more headroom without tuning.
The Bottom Line
ProxySQL 3.0.3 and 3.0.4 are less about flashy features and more about making ProxySQL a smoother, safer proxy in real production conditions—especially if you’re running mixed MySQL/PostgreSQL workloads.
If you’re on 3.0.2 or earlier, jump straight to 3.0.4 to get all of these improvements in one step.