PostgreSQL sink

Role

Backend postgres — registry/observation/plain tables in schema pipeline.
Transport: framework/db/postgres/. Adapter: backend_builtins._Postgres*.

DRTML (inline)

datasets:
  lemma_vocab:
    role: output
    backend: postgres
    kind: registry
    uniq: lemma_token_id
    columns:
      run_id: { type: string, not_null: true }
      lemma_token_id: { type: string, not_null: true }
      token_count: { type: int64, not_null: true }
    postgres:
      connection: postgres_app
      schema: pipeline
      table: lemma_run_staging_v1
      schema_version: "2026.07.3"
      on_conflict:
        target: [run_id, lemma_token_id]
        action: do_update
        update_additive: [token_count]
    checkpoint: { column: doc_id, every_n: 100 }
    metric_defs:
      cardinality: { method: count_distinct, column: lemma_token_id }

DDL vs runtime

When	What
Deploy	ddl_codegen → static/postgres/ → migrate-postgres.sh
Run start	assert_schema_version
Run	INSERT/UPSERT / metric snapshot procs

Forbidden at runtime: CREATE TABLE / ALTER.
Forbidden in platform init: step-specific DDL (bootstrap + generic procs only).

Saturation

See Saturation. Homogeneity uses a single formula B.