Posts
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🤖 Designing a robot that talks with kids
How a robot that talked with kids worked: the body, the parts, the wiring, the software and the cloud, and the reasons behind each choice.
🧁 WAL Cake: Ordered ACKs from Parallel S3 Uploads
How WAL Cake reads the Postgres WAL in order, uploads Parquet files to S3 in parallel, and uses one ring buffer to keep the replication slot ACK in order.
🦉 The Outbox Without an Outbox
The outbox pattern needs durable, ordered, resumable delivery, and database replication already provides it. Postgres' pg_logical_emit_message writes events into the replication stream. A line-by-line explanation of factlib and OwlPost.
🚂 Temporal — Under the Hood
Every SQL statement a Temporal workflow runs against Postgres, and why each one exists. Then Absurd, a 5-table durable-execution engine in one SQL file, does the same job with about a fifth of the statements and 20× the throughput.
💸 1B Payments/Day - TigerBeetle & PostgreSQL
Napkin math and reproducible benchmarks for a ledger at a billion payments a day: TigerBeetle vs PostgreSQL, traced with eBPF down to the io_uring and fsync calls.
🏃 Running 101
How I went from a 38-minute 4K to a 24:45 5K with one goal at a time and one running metric at a time, measured with a Garmin watch. Compare your cadence, ground contact time, and vertical oscillation with Garmin's percentile bands, and get your heart-rate zones in bpm.
🔧 Lost SSH Access to Ec2 ?
Recover SSH access to an EC2 instance by adding a new public key through user data, and why a plain users: block needs one cloud_final_modules line to work.
🏎️ Building pre-owned Car Platform With Valkey - Part 2
How we moved a used-car marketplace's listing page from Django filters on SQL to Valkey: each filter is a sorted set of car ids, a page is their intersection, and a personalised order is computed per request from one unordered set.
🐈 A Cat Stereogram - Dark Mode
How to fuse a white-on-black pair of cats into one: where your eyes aim, why a fingertip helps, how a pair gets depth, and what the exercise does and does not do for your eyes.
🧩 The Psychology of Seeking Help
Five ways engineers ask for help, three ways they take the fix, and where to ask. How to recognise the pattern from the first message and give the help that fits.
📜 The Best Way to Learn Backend Web Development
A plan for your first year of backend development: one stack for six months, three fundamentals learned deeply, one project you extend for months, and a realistic timeline.
🪲 The Tiger Style
A repost of TigerBeetle's coding guide. It ranks safety, then performance, then developer experience, and gives rules for assertions, limits, static memory, batching, and naming.
🚗 Pre-owned Car Platform with Valkey - Part 1
How we served a pre-owned car page in 60 ms from one pre-computed JSON in Valkey, kept it fresh by reading the MySQL binlog through Kafka, and what happens to a price change when each part of that pipeline fails.
🧿 Creating Content
At the end of this, you'll know what stops people from sharing, why talent matters less than knowledge and practice, and when, what, and where to start.
🐘 Postgres - Optimising query
Postgres reads data in 8 KB pages. This post explains why one lookup reads 33,333 pages without an index and 4 with one, when the planner skips an index, how to read EXPLAIN, and what SELECT * and LIMIT save.
♥️ System Design - Tinder
How to design a location-based dating app for 75M daily users: derive the load, precompute each user's deck, find nearby people with geohash cells, check matches without races, and never lose the first message.