Understand how the principle of "store together what is accessed together" is a game-changer for database performance and scalability. By @franckpachot.bsky.social, thanks to @mongodb.bsky.social

A new blog post: MongoDB’s $lookup isn’t like SQL JOINs. It returns related info as arrays in documents, not flat rows. Use $unwind for row-style results, or inner join behavior. And it supports many-to-many with one $lookup on arrays. dev.to/franckpachot...

Meeting many friends at @doagev.bsky.social

My first article on @thenewstack.io is about data locality vs. data independence

Like any database, you can join in #MongoDB, with hash join, nested loop, and indexes. Understanding them and creating indexes (or not) are important for optimal performance. dev.to/franckpachot...

I quickly tested the new query planner in Amazon DocumentDB: dev.to/aws-heroes/a...

Scalable database: query response time stays consistent as data grows. A simple query to compare MongoDB with emulations - typical OLTP with filter, sort, and pagination: dev.to/franckpachot...

I've never realized before that SQL*Plus can tell you when it disconnects "with complications" 🤓

B‑trees face issues like page splits, locks, and buffer pins. LSM‑trees avoid them but raise write amplification. WiredTiger takes a third path: lock‑free B‑trees with hazard pointers for reads and skip lists for writes. Great article on the #MongoDB blog: www.mongodb.com/company/blog...

I'm curious if some @oracleace.bsky.social will be attending AWS re:Invent, given the multi-cloud partnership. Asking because there'll be an event open to advocates, heroes, champions, builders, ambassadors, and user group leaders to celebrate community leaders and meet

Developers — curious to know how you document data model relationships today? www.linkedin.com/posts/franck...

An example of a covering index to avoid fetching large documents in a MongoDB aggregation pipeline dev.to/franckpachot...

I enjoy staying connected with multiple database communities. Even if I share more about one today 🌱🐅, I'm happy to have feedback from others 🅾️🔸️🐘🐬 on what I share

Sad times where tech giant billionaires fire people to build datacenters in a giant game of Monopoly

A migration tool vendor suggests that migration is necessary for improved consistency, reliability, and advanced query capabilities. Yet, success often comes from first understanding your current database. Questioning these claims is the occasion to learn: dev.to/franckpachot...

I'm curious to find out whether Oracle still uses DerbyDB in their Oracle Database Appliances to store the metadata, and what they will replace it with

SELECT DISTINCT ON ... ORDER BY equivalent in MongoDB (and faster) dev.to/franckpachot...

More WiredTiger internals: persisting MongoDB's committed MVCC versions through checkpoints and restarts dev.to/franckpachot...

Trust me I was so against it when I arrived at spark I’ve used it in the past and hated it. but the lack of relations is actually amazing for backfill. it just makes it so simple and painless that I’m willing to live with the mongo of it all

Blog post for September 2025 SQL Developer isn't entirely CBO-friendly. jonathanlewis.wordpress.com/2025/09/24/s...

A closer look at MongoDB Text Search: which terms are indexed for a string, how they're stored, and what formula is used to calculate the query's matching score. Since it's based on Lucene, let's use Lucene tools. dev.to/franckpachot...

Comparing 🍏 to 🍊, and MongoDB to PostgreSQL, with full-text search indexes dev.to/franckpachot...

An example of MongoDB aggregation pipeline compared to the equivalent in SQL/JSON with common table expressions (CTE), from a StackOverflow question: dev.to/franckpachot...

A flexible schema permits arrays in fields without upfront declaration, and filters and indexes (multiple keys per document) use it automatically. MongoDB tracks multikey paths in indexed fields to optimize index scans: dev.to/franckpachot...

MongoDB’s strength is not only in its flexible, document-oriented API, but also in its ability to store documents to disk without random I/O slicing or vacuuming later. Here's how MongoDB persists collections and indexes in WiredTiger: dev.to/franckpachot...

For nearly a decade, MongoDB provided reliable persistence with one of the most robust storage engines. Yet somehow, the oldest jokes keep persisting, too, so here are some facts: dev.to/franckpachot...

MongoDB is popular, inspiring databases to mimic its features on top of RDBMS. Examining execution plans can provide insight into how things work—such as how to simulate multi-key indexes in a database engine designed for single-key indexes on normalized schemas dev.to/aws-heroes/d...

If you update a row/document with the same values, is it still an update, or should the database skip the write? SQL vs NoSQL. dev.to/franckpachot...

Embedding a One-to-Many relationship into JSONB to avoid joins, if over 2KB, hides the join, but does not prevent it. Here's how PostgreSQL TOAST works: dev.to/franckpachot...

SQL or NoSQL? @franckpachot.bsky.social explains how to pick the right model for your app in this #IntelliJIDEAConf session 👉 youtu.be/CuA84bJEjDo

New blog post about comparing and sorting arrays in @MongoDB 👇🏼 It's a long story with a short conclusion to help remind it. dev.to/franckpachot...

🤓 Some geekery (for my #POUG2025 talk) on index dumps and internals to understand how Oracle Database emulates MongoDB multi-key indexes, and where the limitations come from. dev.to/franckpachot...

PostgreSQL makes it easy to fact-check internet myths: read documentation + test with explain analyze 👉🏻 an example: dev.to/mongodb/does... 🤔

Is MongoDB storing documents like heap tables or index-organized tables? 👉🏻 kind of both, a B+Tree optimized for flexible size documents dev.to/franckpachot...

Benchmarks from DbX's vendor showing it's faster than DbY are mainly marketing and serve little purpose in promoting DbX. However, they can help DbY's users spot poor design choices and anti-patterns that made DbY slower than carefully-tuned DbX dev.to/franckpachot...

Query planner transformations on MongoDB documents with flexible schemas can surprise users familiar with SQL databases, which typically have fixed tabular schemas. An example of these subtle differences is explained in a new blog post. dev.to/franckpachot...

Easy to check MongoDB durability (WAL fsync to disk + sync replication to a quorum) dev.to/franckpachot...

Nice to see a public presentation about SQL Assertions by @toonkoppelaars.bsky.social at @doagev.bsky.social my.doag.org/events/userc...

That would obviously apply to Oracle cloud also. They must give out EU stored data about EU customers to US. Very bad idea idea to use major US big-tech www.theregister.com/2025/07/25/m...

ACID properties in @MongoDB: 🔂 Single-document updates wait on conflicts, similar to pessimistic locking, but uses optimistic concurrency control to avoid locks. 🔁 User-managed transactions detect conflicts and enable applications to cancel and retry their transactions. dev.to/franckpachot...

I mainly use query planner hints for troubleshooting, and I rarely use them as workarounds. It's essential to understand whether hints force a plan, affecting the result, or favor one and may be ignored. Here's how hints work in #MongoDB dev.to/franckpachot...

Simulating edge conditions: Running #pgbench with added latency to test client/server transaction logic in SQL (business logic in App or DB?) and compare it with MongoDB’s document model dev.to/franckpachot...

I forgot to add my blog to my @bsky.app bio. Fixed. dev.to/franckpachot Expect new content about #MongoDB, as well as some #PostgreSQL and #AWS databases.

MongoDB: "The documentation is pretty good!" Also MongoDB: www.mongodb.com/developer/pr...

Looking for an AUTO-INCREMENT, BIGSERIAL, or GENERATED ALWAYS AS IDENTITY in MongoDB? Simply use a collection with an atomic increment-and-fetch operation, and choose ACID or not (SQL sequences are not ACID) dev.to/franckpachot...

Old debates about relational 3NF are resurfacing. I revisited Codd’s paper to better understand the original goals of normalization, this time considering today’s developer experience and document data modeling www.linkedin.com/pulse/data-m...

A better database development experience in @intellijidea.com

💚 Welcome the 2025 MongoDB Community Champions! A diverse group from various countries, growing the tech community with professionals from industry, academia, startups, and large companies www.mongodb.com/company/blog...

A document database isn't just a JSON store with flexible schemas; it also integrates flexibility directly into indexes. MongoDB accepts wildcards in index definitions: dev.to/franckpachot.... I've tested the same on MongoDB emulations on top of SQL databases, and they all fail

Adding a column in #PostgreSQL compared to adding a field in #MongoDB: dev.to/franckpachot... (please, tell me if you learned something new about postgres or mongo here, and if you want more content like this)