Crate sources_postgres 

flusso-sources-postgres

The Postgres logical-replication source for flusso: capture row changes over the WAL, backfill existing rows on first seed, and build each index document from the schema’s joins and aggregates.

At a glance

Trait (sources-core)	Role
ChangeCapture	streams thin per-row changes (table + primary key) from a replication slot; confirms progress via an LSN watermark
DocumentBuilder	resolves which documents a changed row affects, then assembles each one. Also implements Catalog (a column’s SQL type + nullability, for index validation)
CaptureProvisioning	reports stream coverage + a privilege verdict for an index’s tables, and provisions the gap (create/extend a publication) when allowed

Re-exports (so callers build a capture without depending on pgwire-replication directly): Lsn, ReplicationConfig, SslMode, TlsConfig.

💡 Did you know — flusso only reads the WAL; it never polls your tables, so follow-mode load on Postgres stays flat regardless of table size.

The traits

• ChangeCapture streams thin per-row changes (table + primary key) from a replication slot and confirms progress via an LSN watermark. The slot advances only as far as the engine has durably written — at-least-once.
• DocumentBuilder resolves which documents a changed row affects and assembles each one. It also implements Catalog, the store-specific half of index validation (a column’s SQL type + nullability).
• CaptureProvisioning takes the tables an index reads, reports stream coverage and a privilege verdict, and — when allowed — provisions the gap by creating or extending a Postgres publication.

Module layout

• cdc/ — change capture. Decodes the pgoutput message stream (the crate-private decoder, fuzzed via the fuzzing feature), tracks relation metadata to extract each changed row’s key, buffers per transaction and emits on commit tagged with the commit LSN, manages the replication slot and publication, and snapshots tables for backfill.
• document/ — document assembly. Resolves a changed row back to the document keys it affects (reverse resolution per join kind), generates one server-side SQL query per document (nested relations assembled with json_build_object / json_agg, so there’s no N+1), and decodes the result into the value tree.

Structs

Lsn

PostgreSQL Log Sequence Number.

PgDocumentBuilder

Builds index documents from a Postgres database, driven by a SourceSpec — the enabled indexes and their schemas, translated from the top-level config by the composition root. Cheap to clone — the pool, spec, and primary-key cache are shared.

ReplicationConfig

Configuration for PostgreSQL logical replication connections.

TlsConfig

TLS/SSL configuration for PostgreSQL connections.

WalChangeCapture

Postgres change capture over logical replication (pgoutput).

Enums

SslMode

SSL/TLS connection mode.