sqlx Code Review

Review Workflow

1. Check Cargo.toml — Note sqlx features (runtime-tokio, tls-rustls/tls-native-tls, postgres/mysql/sqlite, uuid, chrono, json, migrate)
2. Check query patterns — Compile-time checked (query!, query_as!) vs runtime (query, query_as)
3. Check pool configuration — Connection limits, timeouts, idle settings
4. Check migrations — File naming, reversibility, data migration safety
5. Check type mappings — Rust types align with SQL column types

Output Format

Report findings as:

[FILE:LINE] ISSUE_TITLE
Severity: Critical | Major | Minor | Informational
Description of the issue and why it matters.

Quick Reference

Issue Type	Reference
Query macros, bind parameters, result mapping	references/queries.md
Migrations, pool config, transaction patterns	references/migrations.md

Review Checklist

Query Patterns

• Compile-time checked queries (query!, query_as!) used where possible
• sqlx.toml or DATABASE_URL configured for offline compile-time checking
• No string interpolation in queries (SQL injection risk) — use bind parameters ($1, $2)
• query_as! maps to named structs, not anonymous records, for public APIs
• .fetch_one(), .fetch_optional(), .fetch_all() chosen appropriately
• .fetch() (streaming) used for large result sets

Connection Pool

• PgPool shared via Arc or framework state (not created per-request)
• Pool size configured for the deployment (not left at defaults in production)
• Connection acquisition timeout set
• Idle connection cleanup configured

Transactions

• pool.begin() used for multi-statement operations
• Transaction committed explicitly (not relying on implicit rollback on drop)
• Errors within transactions trigger rollback before propagation
• Nested transactions use savepoints (tx.begin()) if needed

Type Mapping

• sqlx::Type derives match database column types
• Enum representations consistent between Rust, serde, and SQL
• Uuid, DateTime<Utc>, Decimal types used (not strings for structured data)
• Option<T> used for nullable columns
• serde_json::Value used for JSONB columns

Migrations

• Migration files follow naming convention (YYYYMMDDHHMMSS_description.sql)
• Destructive migrations (DROP, ALTER DROP COLUMN) are reversible or have data backup plan
• No data-dependent schema changes in same migration as data changes
• sqlx::migrate!() called at application startup

Severity Calibration

Critical

• String interpolation in SQL queries (SQL injection)
• Missing transaction for multi-statement writes (partial writes on error)
• Connection pool created per-request (connection exhaustion)
• Missing bind parameter escaping

Major

• Runtime queries (query()) where compile-time (query!()) could verify correctness
• Missing transaction rollback on error paths
• Enum type mismatch between Rust and database
• Unbounded .fetch_all() on potentially large tables

Minor

• Pool defaults used in production without tuning
• Missing .fetch_optional() (using .fetch_one() then handling error for "not found")
• Overly broad SELECT * when only specific columns needed
• Missing indexes for queried columns (flag only if query pattern is clearly slow)

Informational

• Suggestions to use query_as! for type-safe result mapping
• Suggestions to add database-level constraints alongside Rust validation
• Migration organization improvements

Valid Patterns (Do NOT Flag)

• Runtime query() for dynamic queries — Compile-time checking doesn't work with dynamic SQL
• sqlx::FromRow derive — Valid alternative to query_as! for reusable row types
• TEXT columns for enum storage — Valid with sqlx::Type derive, simpler than custom SQL types
• .execute() ignoring row count — Acceptable for idempotent operations (upserts, deletes)
• Shared DB with other languages — e.g., Elixir owns migrations, Rust reads. This is a valid architecture.

Before Submitting Findings

Load and follow beagle-rust:review-verification-protocol before reporting any issue.