ClickHouse released WalShadow, a tool that replicates PostgreSQL data by reading the physical WAL stream rather than using logical decoding. It decodes heap records directly from the byte stream and writes them as ClickHouse-native blocks. This approach bypasses standard logical replication mechanisms to achieve data synchronization.
- Bypasses logical decoding overhead by reading raw physical WAL bytes
- Decodes heap records internally to generate ClickHouse-native block formats
- Offers an alternative replication path for Postgres to ClickHouse workflows
- Requires careful monitoring as it operates outside standard logical replication