The JusDB Database Engineering Blog

A top-down playbook for high-performance MongoDB: measure with the profiler and explain(), model for access patterns, index by the ESR rule, keep the working set in the WiredTiger cache, pool connections, and scale reads with secondaries and sharding — with flow diagrams for each layer.

Complete MongoDB guide covering document modeling, aggregation pipelines, sharding, replication, and Atlas deployment. Learn when MongoDB is the right choice for your application.

Master MongoDB aggregation pipeline stages — $lookup, $group, $facet, explain plans, and index optimization

Design MongoDB sharded clusters — choose shard keys, manage chunk balancing, and avoid hot shards in production

MongoDB's Slot-Based Execution (SBE) engine introduced a plan cache memory leak affecting certain MongoDB versions — here's how to detect, mitigate, and fix it.

A critical bug in MongoDB 8.0 (SERVER-97368) affects TTL index behavior — causing documents to persist beyond expiration or delete prematurely. Here's how to detect and mitigate it.

MongoDB Atlas M30 costs 5.6x more than equivalent EC2 instances, but self-hosted TCO includes DBA labor that most comparisons ignore. Here's the honest math and when each option wins.

DynamoDB and MongoDB are the two most common NoSQL choices, but cost structures, query flexibility, and operational overhead differ dramatically depending on your access patterns.

MongoDB 8.0 brings significant replication improvements including faster elections, durable oplog writes, and changes to write concern behavior. Here's what changed and how to take advantage of it.

MongoDB indexes fragment over time as documents are inserted, updated, and deleted. Here's how to detect fragmentation, measure its performance impact, and rebuild indexes safely.

An honest comparison of MongoDB and PostgreSQL in 2026 — document model vs relational model, JSONB as a document store, ACID transaction trade-offs, horizontal scaling, licensing, and migration paths.

MongoDB's flexible schema allows fields to be null, explicitly set to null, or simply absent — and these three states behave differently in queries, aggregations, and indexes.