PostgreSQL Field Notes

Notes for the problems that show up after launch: bad plans, awkward migrations, index debt, vacuum pressure, replica lag, and the small decisions that make PostgreSQL easier to operate.

PostgreSQL Topic Hubs

PostgreSQL Guide (Pillar)

pgvector Monitoring Query Optimizer Sizing Slow Query Monitoring Query Monitoring

PostgreSQL Tools

HNSW Tuning Lab Plan Autopsy Index Rollout

Tool Comparisons

Compare PostgreSQL monitoring tools

February 27, 20267 min read

Logical Replication in Postgres: When It Is the Right Tool and When It Isn't

Logical replication is more flexible than physical and more fragile. Use it when you need partial replication, cross-version, or selective sync. Don't use it for HA.

February 26, 20265 min read

Physical Replication Slots: The Lifesaver That Quietly Fills Your Disk

Physical replication slots make sure replicas can catch up after a disconnect. They also make sure your primary's disk fills if a replica is gone and forgotten.

February 25, 20266 min read

Read Replica Staleness in Postgres: The Bug You Will Eventually Meet

Read replicas are eventually consistent. The application's view of "after I wrote, my read should see it" is often wrong by milliseconds, sometimes by minutes.

February 24, 20266 min read

Postgres Failover Readiness: The Drill That Tells You If You Are Lying to Yourself

Failover is mostly fine when you do not need it and broken when you do. Here is how to know which you have.

February 23, 20265 min read

When Replication Slots Eat the Disk: A Diagnostic Walkthrough

If your Postgres disk is growing and you cannot identify the culprit, replication slots are usually the answer. Here is the diagnostic sequence.

February 22, 20266 min read

Postgres Roles and Least Privilege: The Setup That Survives Audits

Most production databases run application traffic as a superuser. This is convenient and wrong. Here is the role hierarchy that takes a few hours to set up and saves you in the worst case.

February 21, 202612 min read

PostgreSQL Replication Monitoring: Lag, Slots, and Failover

Replication health is more than a lag number. Watch replay delay, slot retention, WAL growth, sync state, and the product impact of stale reads.

February 20, 20267 min read

Row-Level Security in Postgres: Strong Defense, Costs You Will Encounter

RLS pushes access control into the database. It is more secure than application-side filters and slightly slower than no filter at all. Here is the framework for using it well.

February 19, 20266 min read

Postgres SSL Connections: Doing It Properly Without Losing a Day

SSL on Postgres is a one-line config change to enable and a multi-day project to do correctly. The default settings are not good enough.

February 18, 20266 min read

Auditing Sensitive Access in Postgres: Patterns That Survive Real Audits

"Did anyone read the customer table outside expected hours" is a common audit question. The answer is harder to produce than it should be unless you set up auditing deliberately.

February 17, 20266 min read

Connection Strings, Passwords, and Secrets: How to Stop Leaking Postgres Credentials

Most Postgres connection strings live in places they should not. Environment variables, config files, scripts, screenshots in Slack. Here is the discipline.

February 16, 20267 min read

AWS RDS Parameter Groups: The Postgres Settings That Actually Matter

RDS exposes hundreds of Postgres parameters through Parameter Groups. About a dozen of them are worth tuning. Here are the ones I always change and why.