Today, we’re announcing WalShadow, an open-source engine that replicates Postgres data to ClickHouse directly from physical WAL. In our benchmarks, transactions committed in Postgres became visible in ClickHouse in around 200 ms, while WalShadow sustained 289K rows/sec, effectively keeping pace with the source Postgres instance. Unlike traditional CDC based systems, WalShadow doesn’t use Postgres logical replication. It consumes the same physical WAL stream used by Postgres replicas, decodes it ...