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Jatin Jain Saraf (JJS) Insights & Blog

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JJS Insights & Reflections

Deep-dive technical articles, career growth strategies, and mindset lessons. Lessons learned from production engineering and life.

Content Type

🌊
EngineeringCulture

The Codebase You Sit In Rubs Off On You

Your habits as an engineer aren't shaped by courses and effort alone; they're shaped by the PRs, teammates, and incidents you sit next to every day.

Aug 11, 2026
5 min read
4 tags
EngineeringCultureSoftwareEngineeringCareerGrowthCodeQuality
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⚡
PostgreSQL

PostgreSQL's Async I/O Engine: Why Your Sequential Scans Just Got 2-3x Faster

For twenty years, every PostgreSQL process read one disk page at a time and waited. PostgreSQL 18 finally lets it ask for many pages at once. Here's what changed under the hood, and how to verify the gain on your own workload.

Aug 8, 2026
4 min read
4 tags
PostgreSQLDatabasePerformanceBackend
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🧭
PostgreSQL

Vector Search in Postgres: What pgvector's Indexes Actually Cost You

Adding a vector column and calling it a day works fine in a demo. In production, it means picking between HNSW and IVFFlat, understanding what "approximate" actually costs you in recall, and watching index build time and memory explode as your embedding table grows. A practical look at pgvector's index internals and the tradeoffs nobody mentions in the quickstart.

Aug 5, 2026
10 min read
5 tags
PostgreSQLDatabaseAIBackendSoftwareEngineering
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🧯
System Design

The Three Layers of Failure Isolation: Timeouts, Circuit Breakers, and Load Shedding

500 requests a second are hitting a dependency that is completely dead. Every one gets a clean timeout after 2 seconds, exactly as configured. And you are still down. Three patterns, stacked in order, timeouts and retries, circuit breakers and bulkheads, backpressure and load shedding, each one picking up exactly where the last one's guarantee runs out.

Aug 3, 2026
21 min read
5 tags
System DesignResilience EngineeringDistributed SystemsBackend DevelopmentArchitecture
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🔌
PostgreSQL

Connection Pooling in the Serverless Era: Five Failure Modes

Your database CPU is at 20%, your slowest query is 12ms, your slow-query log is empty, and your p99 is three seconds. Five ways connection pooling breaks in serverless and autoscaled deployments, why each one disguises itself as something else, and what every fix actually costs.

Aug 2, 2026
18 min read
5 tags
PostgreSQLDatabaseServerlessPerformanceBackend Development
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🐘
PostgreSQL

PostgreSQL 19 vs. 18: What Actually Changed, Feature by Feature

Every major PostgreSQL release gets the "this changes everything" headline treatment. Here's the honest version: what specifically didn't work in PG18 that PG19 now fixes, feature by feature, with the real production tradeoffs — from REPACK CONCURRENTLY to SQL/PGQ to parallel autovacuum.

Jul 27, 2026
15 min read
4 tags
PostgreSQLDatabaseBackendSoftwareEngineering
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🔁
Backend

Idempotency Keys: How to Make Retries Safe in Distributed Systems

A network blip retries a payment request. Without an idempotency key, the customer is charged twice. Here is why retries are unavoidable, how idempotency keys make them safe, and when a blockchain indexer replaying the same block twice must not double-count it.

Jul 24, 2026
9 min read
4 tags
BackendSystem DesignDistributed SystemsArchitecture
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🧠
DSA

How the LRU Cache Actually Works and Why Redis, Browsers, and Postgres All Approximate It

Every fast system you use eventually has to decide what to throw away. The Least Recently Used policy is the answer nearly all of them land on, here's the two-structure trick that makes it instant, and why Redis, your browser, and Postgres all quietly cheat on the textbook version at scale.

Jul 21, 2026
6 min read
5 tags
DSASystem DesignCachingRedisData Structures
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📝
PostgreSQL

Why a Single ALTER TABLE Can Take Down Your Whole Database

A routine ALTER TABLE queues behind one slow query — and every SELECT that arrives after it queues too, even though they'd normally run just fine together. This is the PostgreSQL locking mechanic behind some of the ugliest production outages, and the two settings that prevent it.

Jul 15, 2026
6 min read
5 tags
PostgreSQLDatabaseBackendSQLProduction Incidents
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