🧁 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.
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 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.
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.