HighPR-scopeC# Plug & play

Add database indexes for query optimization

Index frequently filtered or joined columns and verify with query plans.

Why this matters

Proper indexing drastically improves query performance and reduces timeouts.

Side-by-side examples engineers can pattern-match during review.

Avoid

// No index on Email; queries scan entire table

Prefer

// Migration: CreateIndex("Users", "Email", unique: true);

Bad

WHERE Email = @p0 (no index)

Good

CREATE INDEX IX_Users_Email ON Users(Email)

From the same buckets as this rule.

Critical
Block risky database migrations (locking ops, downtime risk)
Review SQL/database migrations for operations that can lock large tables or cause downtime. Examples: creating indexes without CONCURRENTLY (Postgres), ALTER COLUMN TYPE on big tables, adding NOT NULL without backfill, long-running updates without batching. Require an online migration strategy (CONCURRENTLY, backfill in batches, dual-write/expand-contract) and a rollback plan.
migrations-backward-compatdatabase-query-performance
High
Add database indexes for query performance
Index columns used in WHERE/JOIN/ORDER and enforce uniqueness where applicable.
database-query-performance
High
Add foreign key constraints in migrations
Enforce referential integrity with add_foreign_key and matching indexes.
database-query-performancemigrations-backward-compat