PostgreSQL
3 engineering logs on PostgreSQL. Newest first.
- fsync is the only thing between you and data loss, and it is slower than you think
Why a successful write() means nothing, what fsync actually costs in the cloud, and why synchronous_commit off and fsync off are not the same knob despite being discussed as if they were.
- Decoding isolation levels: I built a toy DB to force dirty reads and phantom reads
Why the ANSI isolation table does not describe your database, what a phantom read actually is at the index level, and why snapshot isolation still lets two correct transactions corrupt each other.
- AI agents break connection pooling by holding the slot while they think
Agents keep pooled DB connections open for LLM inference, exhausting pools and evicting buffer cache. Decouple reasoning from data, route agents to replicas, and never hold a connection across an inference call.