BigQuery coverage-gap analysis: historical

What remains useful

The analysis identified categories that still belong in release qualification:

1. parser or transpiler acceptance;
2. actual execution behavior;
3. silent semantic differences;
4. DuckDB engine differences;
5. REST or Storage API compatibility;
6. compatibility stubs that return empty or permissive responses; and
7. cloud control-plane behavior that cannot be inferred from a local emulator.

These categories are more durable than the individual April 2026 findings.

What changed

Newer dependency evidence includes bounded implementations or compatibility paths for features that the historical analysis called absent, including scripting, materialized views, external data, broader metadata, grouping extensions, TABLESAMPLE, and search/vector behavior. Those additions remain feature-specific and do not establish assembled LocalCloud release parity.

Current source of truth

Use the BigQuery emulator feature reference and BigQuery service contract. They preserve release-unverified status until the dependency revision, dependency image digest, assembled image digest, client qualification, evidence path, and release association are recorded together.

Production BigQuery remains required for IAM, quotas, billing, reservations, audit behavior, regional behavior, distributed performance, and any feature whose semantics are not explicitly qualified.