Database Query Performance

Priority: P0 (CRITICAL)

Slow query work starts with the query shape and evidence, not with random index creation.

Rules

• Capture the exact query, parameters, and access path.
• Run explain or equivalent plan inspection before adding indexes.
• Match indexes to filter, join, sort, and coverage needs.
• Fix N+1 at the query pattern or loading strategy, not by caching first.

Verify

• Explain plan was reviewed.
• Proposed index maps to a named query path.
• Write cost of the index is acceptable.
• Pagination or batch loading avoids deep scans or N+1 loops.