This post was originally published in January 2024 and was updated in April 2025.
Thinking about a PostgreSQL upgrade? Here’s what trips teams up (and how to get it right)
Most upgrades are welcome. New phone OS? Great. Window seat on a flight? Even better.
Upgrading PostgreSQL should feel the same, as it usually means better performance, more features, and improved security. But anyone who’s done it knows: this isn’t a one-click operation. It’s not just “apply patch, get improvements.”
PostgreSQL upgrades come with real risk. Even experienced DBAs can hit snags like downtime, failed extensions, broken compatibility, or worse, data loss. And without a vendor behind the scenes holding your hand, it’s up to your team to get it right.
In this post, we’ll walk through the most common PostgreSQL upgrade errors and how to avoid them. If you’re planning an upgrade soon, this is your chance to learn from other people’s mistakes instead of repeating them.
Common PostgreSQL upgrade errors
Lack of comprehensive planning
Planning isn’t optional, as it’s the part that holds the rest of the upgrade together. And yet, it’s often rushed, skipped, or treated like a checklist someone else will figure out.
That’s usually where the problems start.
An upgrade that hasn’t been fully thought through can lead to everything from minor hiccups to serious data loss or extended downtime. And if you don’t account for how your application behaves, what your hardware looks like, or which features might break, you’re setting yourself up for unnecessary surprises.
Here’s what smart teams do before the upgrade ever begins:
- Read the release notes. Don’t stop at the headline features. Look for what’s been deprecated, changed, or removed.
- Verify your backups. Make sure they’re recent, complete, and restorable. You do not want to discover backup corruption during rollback.
- Test in staging. Clone your environment and run the upgrade there first. Treat this as your dry run and take it seriously.
- Check application compatibility. That one extension you forgot about could break everything. Validate key features before you go live.
- Review your hardware. New PostgreSQL versions can introduce performance shifts, so make sure your system is ready for them.
Carrying over old configs without a second look
PostgreSQL’s default configuration is intentionally minimal. It’s built to be broadly compatible, not to run fast, scale well, or match your workload out of the box. That’s your job.
And most teams do the work. They tune memory, tweak connection limits, optimize I/O. But during an upgrade, it’s easy to forget just how much those settings matter.
A common mistake is copying your old files into the new version without reviewing what’s changed. New PostgreSQL releases often introduce new parameters, modify defaults, or retire older ones entirely. What worked fine in v13 might not work the same way in v16, or worse, it could actively hold you back.
If you don’t review and adapt your configuration:
- You could miss out on new performance or security enhancements
- You might inherit broken behavior or masked inefficiencies
- Your database may become harder to troubleshoot when something goes wrong
Keep in mind: Upgrades aren’t just about the data. They’re a chance to revisit your configuration and make sure your database is set up to perform at its best, not just carry forward whatever “mostly worked” last time.
Not knowing when a “simple update” isn’t so simple
PostgreSQL has two types of releases:
- Major versions (like v14 → v15) come out once a year
- Minor versions (like v15.4 → v15.5) roll out every few months
And here’s where many teams slip up: you can’t treat major and minor upgrades the same way.
When you move between major versions, PostgreSQL’s internal data format often changes. That means you can’t just swap out binaries and restart the server. You’ll need to use tools like pg_dump / pg_restore or run pg_upgrade to migrate data safely. It’s a real upgrade, and it requires planning, testing, and time.
But when you’re upgrading within the same major version (say, v15.4 to v15.5), the process is much simpler. In most cases, you can stop the server, replace the binaries, and start it back up.
So ask yourself: Do you really need that brand-new major version right now? If you’re only chasing a bug fix or a security patch, staying within your current major version and jumping to the latest minor release can be a smarter, safer move.
Side note: PostgreSQL strongly recommends that all users run the latest minor release for your chosen major version.
Error #4: Leaving your extensions behind
One of PostgreSQL’s biggest strengths is how extendable it is. You’re probably running at least a few extensions, maybe pg_stat_statements, PostGIS, pgAudit, or something more custom. They’re part of what makes your database useful, powerful, and tailored to your workload.
But here’s where upgrades trip people up: extensions don’t update themselves. And they’re not always compatible with newer versions of PostgreSQL out of the box.
If you forget to reinstall, update, or check compatibility for your extensions during the upgrade, you could be setting yourself up for:
- Application failures
- Performance regressions
- Lost functionality
- Missed security fixes that came with newer extension versions
And it’s not just extensions. Don’t forget about external libraries, custom modules, and anything else that plugs into your database. These dependencies need to be part of your upgrade plan too.
What to remember: PostgreSQL upgrades don’t just touch core binaries; they impact everything around them.
Get the PostgreSQL Extension Handbook today!
Error #5: Skipping the test drive
Upgrades don’t break things on their own; untested upgrades do.
This one’s simple. If you don’t test your PostgreSQL upgrade like it’s production, you’re leaving the outcome up to luck. And when problems show up after go-live, they’re harder to fix, harder to trace, and way more expensive to clean up.
We get it. Testing takes time. But skipping it, or only doing the bare minimum, leads to:
- Broken application logic
- Slower query performance
- Data mismatches or loss
- User-facing bugs that should’ve been caught earlier
Pro-tip: Don’t settle for “it didn’t throw an error.” You want “it behaves correctly, it performs well, and it’s ready.”
Error #6: Overlooking compatibility changes
Every new PostgreSQL version brings something new to the table, and sometimes in ways that don’t play nicely with your current setup.
SQL syntax changes. Built-in functions behave differently. Reserved keywords shift. Default settings evolve. And if your application isn’t prepared for those changes, things can break in subtle (or very not-so-subtle) ways.
Compatibility isn’t just a “nice to check.” It’s one of the biggest reasons upgrades fail in production.
Here’s how teams set themselves up for fewer surprises:
- Review the release notes. Yes, all of them. Look for deprecated features, altered behavior, and compatibility warnings.
- Scan your queries and functions. If you’re using anything complex or vendor-specific, double-check it still works as expected.
- Test app behavior in staging. It’s the only way to catch those “weird edge cases” before users do.
Worth noting: Don’t assume your queries and code will just work. Confirm it. Catching an incompatibility now is a quick fix. Catching it post-upgrade is a support ticket waiting to happen.
Error #7: Skipping the backup
This one sounds obvious, but it still happens. Whether it’s overconfidence, a missed step, or just bad timing, failing to back up your PostgreSQL database before an upgrade is one of the riskiest mistakes you can make.
Things go wrong. Compatibility issues. Hardware hiccups. Broken extensions. Even just human error. A reliable, restorable backup is what separates a frustrating rollback from a catastrophic loss.
And backups aren’t just your safety net if something fails; they’re how you test safely. Having a clean copy of your environment means you can run trial upgrades in staging, spot issues in advance, and move forward with confidence.
If you haven’t tested your backups lately, or worse, don’t know if they’re restorable, you’re trusting the process a little too much.
Backups make everything else possible. Without them, every upgrade step carries real risk. With them, you’re free to test, experiment, and recover when you need to.
Error #8: Assuming downtime won’t be a big deal
Plenty of teams go into an upgrade thinking, “It won’t take long.” And maybe it won’t. But if that’s your entire plan for managing downtime, you’re already taking a risk.
Even with the right tools and experience, most PostgreSQL upgrades still need some breathing room. Something always takes longer than expected, whether it’s waiting on a file system sync, troubleshooting a failed extension load, or fixing a config that suddenly doesn’t apply.
And while plenty of guides and vendors promise “zero downtime” PostgreSQL upgrades, it’s worth reading the fine print. Those setups typically rely on specialized replication methods, high-availability infrastructure, or teams that have done it dozens of times before.
If this is your first upgrade (or even just your first in a while), aiming for perfection is setting yourself up for panic.
A better approach:
- Plan a realistic maintenance window
- Pad it with buffer time for the unexpected
- Communicate clearly with stakeholders
- Treat zero downtime as a goal, not a guarantee
One common trap: Believing downtime is only measured in minutes. If the app is “up” but things are broken, slow, or acting weird, your users won’t care that the database technically restarted on time.
🚨Need immediate help with database outages or critical performance issues? Learn about Percona Emergency Support.
Error #9: Rushing the upgrade
Upgrading PostgreSQL isn’t something you can just push through on a Friday afternoon. And yet, that’s exactly how a lot of upgrade trouble starts.
Tight timelines. Last-minute approvals. Pressure to “just get it done.”
We get it, but rushing through the process often creates more problems than it solves.
Cut corners on testing, and you miss the weird edge cases that only show up under load. Skip the compatibility review, and suddenly that one legacy feature breaks everything. Try to move too fast, and the thing you were trying to avoid (ahem, downtime) ends up lasting longer than anyone planned for.
Speed only feels productive. But if it comes at the expense of preparation, clarity, and control, you’re not saving time. You’re just deferring the pain.
Don’t trade time now for time lost later. Slow down where it matters. Upgrades don’t have to be perfect, but they do have to be safe.
Error #10: Treating go-live like the finish line
The upgrade’s done. No errors. Everything looks good. Time to move on, right?
Not quite.
One of the most common mistakes teams make is treating a successful PostgreSQL upgrade as the end of the story. But it’s what happens after go-live that tells you whether the upgrade really worked.
Performance shifts, query slowdowns, and unexpected user complaints often don’t surface until real traffic starts flowing through the system. And if you’re not watching closely, you’ll miss the signals.
Here’s what well-prepared teams monitor post-upgrade:
Tools like Percona Monitoring and Management (PMM) can give you real-time visibility into what’s happening, so if something’s off, you can catch it before your users do.
Think of monitoring as part of the upgrade process, not an afterthought. Until you’ve seen how the new version behaves in production, your job isn’t done.
Error #11: Waiting too long to ask for help
PostgreSQL upgrades are doable. But that doesn’t mean you have to do them alone.
Too many teams power through uncertainty because they think asking for help means they’re not ready. In reality, it’s the opposite. Knowing when to bring in a second set of eyes, or a partner who’s done this dozens of times, can save you from real trouble.
If you’re upgrading a complex, heavily customized PostgreSQL environment, or if it’s your first time running point on a major upgrade, bringing in experts isn’t a shortcut. It’s a smart risk reduction strategy.
The right help can:
- Spot compatibility issues you didn’t think to check for
- Optimize your upgrade process to reduce downtime
- Validate your fallback plan before you actually need it
- Take pressure off your internal team so they can focus on what matters most
What feels like “getting help” is often just “doing it right.”
If you’re staring down a PostgreSQL upgrade and not sure you’ve covered everything, it’s worth talking to someone who’s been there. Learn about Percona Upgrade Services.
The upgrade is worth it. Just don’t go it alone.
A successful PostgreSQL upgrade isn’t about checking a box; it’s about setting your environment up to run smoother, faster, and with fewer surprises. And that takes more than just knowing what version you’re upgrading to. It takes planning, testing, reviewing, backing up, monitoring… and sometimes, asking for help.
You can’t eliminate every risk, but you can be ready for them.
If you’re in the middle of planning an upgrade (or about to start), don’t wing it. We’ve put everything we’ve learned from years of PostgreSQL upgrades into one resource to help you get it right from the start.
It’s practical. It’s pressure-tested. And it’s built to help teams like yours avoid missteps and move forward with confidence.
FAQs
What happens if we delay PostgreSQL upgrades?
Delaying upgrades might feel like the safe move, but it can quietly create bigger problems over time. You miss out on important performance improvements, security patches, and compatibility with modern tools and extensions. And the longer you wait, the harder the upgrade usually becomes, especially if you end up skipping multiple major versions. PostgreSQL upgrade errors get bigger when you’re behind by a few years.
Why does planning matter so much before a PostgreSQL upgrade?
Because most upgrade problems start before anything actually breaks. Solid planning gives you the chance to catch red flags early, like breaking changes, outdated extensions, or incompatible application logic. It’s not about making a massive binder. It’s about knowing what’s changing, testing in a safe environment, verifying your backups, and making sure your configs and apps are ready for what’s next. When you plan well, the upgrade feels boring, and that’s a good thing.
Can we skip testing if everything looks fine after the upgrade?
Short answer? No.
Even if the upgrade technically “works,” that doesn’t mean everything is working correctly. Queries might behave differently. Performance might take a hit. Application features could break in subtle ways. That’s why testing—functional, performance, and real-world usage testing—is so important. It’s your chance to catch problems before users find them. And that’s what turns a risky upgrade into a confident one.
