Sources

A source is where data comes from. SQLLoad has four kinds:

kind	Reads	Tables	Declared in
postgres	Tables of a Postgres database, with binary COPY	One per matching source table	sqlload.toml
postgres_cdc	A Postgres database’s inserts, updates and deletes, from a logical replication slot, after a first snapshot	One per matching source table	sqlload.toml
files	Parquet, CSV, JSON or NDJSON files in S3 or a local folder	One per source	sqlload.toml
Python	Whatever a Python function yields: dicts, Arrow data, JSON bytes, HTTP jobs	One per decorated function	Python, under python_paths

Every source loads into a target: its destination, or the project’s default_target. Settings that shape tables (write_strategy, unique_key, cursor_column and the rest) can be set on the source as defaults for all its tables, and per table. See sqlload.toml for the full list.

Each kind has its own page:

• Postgres: choosing tables and columns, masking, and how tables are read.
• Postgres changes: streaming changes from a replication slot into DuckDB, Snowflake or Parquet files, on a schedule or continuously, and what to watch on the server.
• Files: formats, partitions, which files load, and files the destination reads itself.
• Python: any API, SaaS or custom source as a table, including REST APIs that run entirely in Rust.