Engineering
5 min
Schema migration without downtime
Why renaming a column breaks production, and the four step pattern that turns a migration into a Tuesday afternoon task.
migrationexpand-contract
Read articleArchive · Engineering
Everything I have written about Engineering.
9 articles published in this category. Use the search to narrow by tag, or go back to the full archive.
9 articles
The whole archive
Engineering
6 min
The five resilience patterns that stop a cascading failure
How one slow secondary dependency takes down the whole system in ninety seconds, and the five patterns that prevent it.
resiliencearchitecture
Read articleEngineering
5 min
Saga and outbox: a transaction without a distributed transaction
You need to debit one account and credit another, and they live in different databases. The two patterns that solve it in practice, and what to avoid.
distributed-systemsmicroservices
Read articleEngineering
5 min
CAP, PACELC and the consistency models
CAP is the most quoted and most badly stated theorem in distributed computing. This article fixes the statement and shows the vocabulary you actually use day to day.
distributed-systemsarchitecture
Read articleEngineering
6 min
Sharding: a decision guide
Sharding is the most irreversible decision in a data system. This is the guide to deciding whether you need it and, if you do, how to pick the key.
shardingdatabases
Read articleEngineering
6 min
Indexes, EXPLAIN and the slow query
How an index works on the inside, why column order decides everything, and how to read an execution plan to know what to do.
postgresdatabases
Read articleEngineering
5 min
Caching: the four traps nobody anticipates
Adding a cache is easy. The hard part is living with the four consequences it creates, and all four have known solutions.
cacheperformance
Read articleEngineering
5 min
Latency, throughput and percentiles: the guide that settles the argument
Your average latency is lying to you. The three concepts that turn 'the system is slow' into a sentence with a number, an endpoint and a percentile.
performancesre
Read articleEngineering
4 min
The idempotent webhook: the bug that only shows up in production
Every gateway redelivers webhooks. If your handler is not idempotent, you will find out on the day the same sale gets counted three times.
backendwebhooks
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