#postgresql

Engineering at Scale

Engineering at Scale 11 min read

What is connection pooling, and how does it work?

Why opening database connections is expensive, how pools lend and reuse them, two-tier pooling on large systems, Django's pool options, and the settings that matter.

PS Prajjwal Sinha Sep 24, 2026

Engineering at Scale

Engineering at Scale 10 min read

Point-in-time recovery in Postgres: WAL, backups, restores

Restore Postgres to the second before a mistake: base backups and WAL archiving, recovery settings, pgBackRest, WAL-G and managed services, retention, and restore testing.

PS Prajjwal Sinha Sep 19, 2026

Engineering at Scale

Engineering at Scale 9 min read

PgBouncer explained: pooling modes, settings and pitfalls

Session, transaction and statement pooling, what breaks in transaction mode, key pgbouncer.ini settings, PgBouncer vs Pgpool-II and managed proxies, and production tips.

PS Prajjwal Sinha Sep 2, 2026

Engineering at Scale

Engineering at Scale 7 min read

Connection pool size: how to calculate it with Little's Law

Size database pools, Gunicorn workers and pods from real numbers with Little's Law, see why bigger pools slow Postgres down, and follow a worked exam-day example.

PS Prajjwal Sinha Aug 25, 2026

Engineering at Scale

Engineering at Scale 8 min read

Postgres too many connections error: causes and fixes

What 'sorry, too many clients already' means, how to find the culprits in pg_stat_activity, quick relief during an incident, and why raising max_connections isn't the fix.

PS Prajjwal Sinha Aug 21, 2026

Engineering at Scale

Engineering at Scale 7 min read

Postgres materialized views: query-level caching

Precompute leaderboards and reports inside PostgreSQL: create and index materialized views, refresh them concurrently, schedule refreshes, and know the alternatives.

PS Prajjwal Sinha Jul 20, 2026

Engineering at Scale

Engineering at Scale 9 min read

How database indexing works, with Postgres examples

B-trees in plain English, reading EXPLAIN ANALYZE, composite, partial and covering indexes, what indexes cost, and adding them to a live Postgres table safely.

PS Prajjwal Sinha Jul 11, 2026

Engineering at Scale

Engineering at Scale 9 min read

Read replicas and database replication explained

How PostgreSQL streaming replication works, synchronous vs asynchronous commits, routing reads in Django, handling replication lag, and replicas for failover.

PS Prajjwal Sinha Jul 8, 2026

Engineering at Scale

Engineering at Scale 10 min read

Zero-downtime database migrations: expand and contract

Change a live Postgres schema without locking students out: expand and contract, lock timeouts, concurrent indexes, NOT VALID constraints, batched backfills, safe Django migrations.

PS Prajjwal Sinha Jun 9, 2026

Engineering at Scale

Engineering at Scale 9 min read

Sharding vs partitioning: how databases split data

Partition inside one server before you shard across many: Postgres declarative partitioning by date, shard keys for multi-institute platforms, the costs of sharding and when it pays.

PS Prajjwal Sinha Jun 6, 2026