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.

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SQL Server MariaDB MySQL pgvector and RAG Indexes Slow Queries Locks and Transactions Backups and Durability Replication and WAL Connections and Pooling CPU, Memory, and I/O Vacuum and Bloat Cloud Providers

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.

February 15, 20266 min read

AWS Aurora Postgres Replica Lag: Different from Vanilla, Different to Diagnose

Aurora's replica lag has different mechanics than vanilla streaming replication. The dashboard metric "replica lag" can be misleading. Here is what it actually measures.

February 14, 202613 min read

PostgreSQL Locks and Deadlocks: Detection, Prevention, and Triage

Lock incidents feel mysterious because the database looks idle while requests wait. The fix starts with blockers, waiters, transaction age, and code paths that take locks in different orders.

February 13, 20265 min read

Google Cloud SQL Maintenance Windows: What Actually Happens and What to Plan For

Cloud SQL maintenance windows are mostly fine and occasionally not. Here is what happens during them, what gets restarted, and how to make sure your application survives.

February 12, 20266 min read

Azure Database for Postgres Flexible Server: The Settings Worth Tuning

Azure Flex's defaults are conservative. The Server parameters blade is where most of the meaningful tuning happens. Here are the parameters I always touch.

February 11, 20267 min read

Running Postgres on Kubernetes: Lessons From the Operators That Almost Worked

Postgres on Kubernetes is feasible now in a way it was not five years ago. The operators are mature, the storage is good enough, and the failure modes are tractable. Here is what to know.

February 10, 20265 min read

N+1 Queries in Postgres: The Bug ORMs Make Easy and the Fix That Sticks

N+1 is the most common ORM-induced performance bug. The query count tells the story; the application code makes it impossible to spot at review time.

February 9, 20266 min read

Prepared Statements in Postgres: When the Generic Plan Bites

Prepared statements skip the planning step on repeated execution. Sometimes that is a 5x speedup. Sometimes it is a 50x slowdown. Knowing the difference matters.