To increase max_connections in Postgres, run ALTER SYSTEM SET max_connections = N; (or edit postgresql.conf) and restart the server — a reload alone won't apply it, because max_connections is a postmaster-context parameter read once at startup. That's the easy part. The part that bites you three days later is sizing that number against real RAM, …
PostgreSQL transaction ID wraparound happens when the 32-bit XID counter runs out of safe room and the database stops accepting new writes to protect committed data from silently disappearing. It's not corruption — it's a deliberate safety interlock. Here's the mechanism, the exact diagnostic queries, and the recovery path that actually works. 📖 Read the …
Postgres Free Space Map: Why Deletes Don't Shrink Tables Why doesn't Postgres delete free disk space? You ran DELETE FROM events WHERE created_at < now() – interval '90 days'. It reported 40 million rows deleted. You ran VACUUM ANALYZE events afterward, like a responsible adult. Then you checked: 📖 Read the full guide: Postgres Free …
Partition Pruning Isn’t Magic — Here’s When It Actually Works A few weeks ago I sat down with a team that had just “fixed” a slow dashboard by partitioning a 12‑million‑row orders table by month. One hundred partitions, clean range boundaries, no more full‑table scans. Then they showed me the week‑end report query, and the …
It’s 02:17, your phone buzzes. pg_stat_statements says query f8472a91 has a mean runtime of 6.2 seconds over the last hour. The raw text is a six-table join with a couple of sub-selects. You copy it, paste it into a psql session, slap EXPLAIN (ANALYZE, BUFFERS) on front, and get a tight index scan that finishes …
Postgres jsonb_array_elements: Turn JSON arrays into queryable rows inside SQL The problem: JSON payloads jammed into a column We have all seen it in production systems: an upstream API sends down a nested payload, and instead of designing a proper relational schema, someone decides to dump the raw JSON straight into a single jsonb column. …
Two Replication Mechanisms, Not Two Flavors of the Same Thing Before choosing between Postgres replication strategies, it is helpful to reference our companion video, which steps through the visual layout of these architectures. That video serves as a quick visual guide, but this article cuts straight to the underlying machinery. We often talk about replication …
Zero Downtime Postgres Major Upgrade: Replacing pg_upgrade with Logical Replication Let's talk about Postgres major upgrades. If you search for solutions, the standard recommendation is almost always pg_upgrade with the –link flag. It is fast, but it is also a binary choice. Once you run it, your old cluster is modified, and your new cluster …
The 'password you never set' prompt isn't a bug — it's pg_hba.conf doing exactly what you told it The moment it happens You just installed PostgreSQL. You followed the getting-started guide, or maybe you didn't — maybe you just ran brew install postgresql or apt install postgresql and typed psql to see what would happen. …
Postgres vs Redis, Mongo, RabbitMQ: The Real Decision Framework I’ve consolidated stacks under a deadline with production on fire. I’ve also ripped Postgres back out six months later and put Redis back where it belonged — on its own instance, doing a single job. No hedging. There’s a sweet spot where a single Postgres database …