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Skill · Version 1.0.0

Review migration rollout

Reviews a planned game-data migration before release. Checks existing saves, concurrent server versions, long-running updates and whether recovery can restore data as well as code.

migration-rollout-review

Agents using this skill

See how it helps

When is it useful?

Use before approving a production schema or persisted-format transition.

What does it help you do?

  • Examines existing records and constraints for incompatible assumptions.
  • Checks deployment order while old readers and writers remain active.
  • Assesses long locks, backfill cost and data recovery limits.

Try asking this

Review a proposal to split one player inventory table into owned items and equipped slots. Check old-client reads, concurrent trades, partially migrated players and the backfill's locking cost. Require concrete validation and recovery steps before approving removal of the old fields; a successful schema change alone is insufficient.

Detailed documentation

Read the skill’s original instructions, examples and checks in their authored language.

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Migration & Rollout Review

Use this skill when reviewing changes that include database schema migrations, data transformations, storage format updates, or environment configuration changes.

Workflow

  1. Verify safety against existing production data:
    • Never evaluate a migration only against an empty test database. Check what happens when tables already contain existing rows:
      • Adding a NOT NULL column without a safe DEFAULT or backfill step will fail on non-empty tables.
      • Adding a UNIQUE constraint or narrowing a column type will fail if legacy rows contain duplicates or out-of-range values.
      • Dropping or renaming a column/table while code or views still reference it causes immediate runtime errors.
  2. Check version coexistence and rollout order (Expand & Contract):
    • Verify whether the migration and code change can deploy safely:
      • Does old code break if the migration runs seconds before the new application process starts?
      • Does new code handle legacy rows created before the migration (e.g., nullable fields, older JSON schema versions, missing metadata)?
  3. Audit performance, locking, and rollback safety:
    • Check whether missing indexes on new foreign keys or filter columns will cause full-table scans as data grows.
    • Flag migrations that rewrite or lock large tables synchronously during request handling without batching.
    • Verify whether the change is reversible (or has a documented forward-fix path) if a rollback is required after deployment.
    • Coordinate deep database engine specifics with the database and DevOps specialists.

Included files 1

  • SKILL.md