Snowflake moved Postgres change data capture into an extension that writes Iceberg change logs

Sources: primary, discussion
Summary: Snowflake's engineering blog post, dated 2026-07-23, describes replacing an external Postgres replication connector with a Postgres extension named snowflake_cdc. The extension runs inside the source database and writes change logs in Iceberg format, pushing batches rather than having a reader pull from the replication slot. Snowflake calls the feature data mirroring and lists it as public preview.
Why it matters: Pushing change batches from inside Postgres puts schema changes, snapshots, and row changes on one timeline, which is the coordination problem that makes external CDC connectors fragile.