How to Add a Data Diff Check in a Pull Request

A data diff compares the PR-built model to production so reviewers see exactly which rows and columns changed.

Build the changed models in CI, then run recce (or data-diff) to compare them against the production relations and post a summary.

Steps

• Build changed models against the CI schema.
• Run recce run with the production manifest as the base.
• Attach the recce summary as an artifact or PR comment.

Workflow

steps:
  - uses: actions/checkout@v4
  - run: pip install dbt-snowflake==1.8.0 recce
  - run: aws s3 cp s3://dbt-artifacts/manifest.json target-base/manifest.json
  - run: dbt build --target ci --select state:modified+ --defer --state target-base
  - name: Run data diff
    run: recce run --target-base-path target-base
  - uses: actions/upload-artifact@v4
    with:
      name: recce-report
      path: recce_state.json

Gotchas

• Diff a key subset of columns for wide tables so the comparison stays cheap.
• A large diff is a signal to review, not always a failure; decide which diffs should block.

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