Database Tech with Fexingo: SQL, NoSQL, and Data Storage Conversations

Lucas and Luna dig into the CAP theorem — consistency, availability, and partition tolerance — and why you can't have all three in a distributed database. They use a concrete example: a real-world fintech firm that chose availability over consistency and paid for it with a double-spend incident. They explain how DynamoDB, Cassandra, and Spanner each make different CAP tradeoffs, and why the 'pick...

In this episode of Database Tech with Fexingo, Lucas and Luna explore write-ahead logs (WAL) — the unsung hero of database durability. They break down how PostgreSQL's WAL works, using a concrete example of a banking transaction to illustrate the 'log first, write later' principle. Lucas explains the mechanics of checkpointing, how WAL enables point-in-time recovery, and why it's critical for cras...

Lucas and Luna drill into one of the trickiest decisions in distributed databases: choosing a shard key. They walk through a real-world example where a social media startup used user ID as its shard key, hit a 'hot partition' that crashed their database, and had to re-shard 200 million records live. Along the way they explain sharding basics, the difference between ranged and hashed keys, and why...

Lucas and Luna dive into the hidden bottleneck that plagues most production databases: poor indexing. Using a real-world case from a mid-size e-commerce company, they show how one missing composite index caused a 47-second query that should have run in 200 milliseconds. They explain B-tree vs. hash indexes, clustered vs. non-clustered, and why covering indexes can eliminate table scans entirely. N...

In this debut episode of Database Tech with Fexingo, Lucas and Luna dive into a real-world disaster: a fast-growing e-commerce startup that lost an entire day of sales because of one poorly written SQL query. They break down how a simple missing index turned a two-millisecond lookup into an 18-hour table scan, what the engineering team could have done differently, and why this case study is a perf...