Mid-levelMid (3–6 yrs)C#.NETSQLMicrosoftAmazonTCS
EF Core N+1 and split queries
How do you diagnose and fix N+1 queries in EF Core for an Orders+Items API?
Answers use simple, clear English.
Quick interview answer
Enable sensitive logging / ToQueryString / MiniProfiler. Symptom: 1 query for orders + N for items. Fix: Include/ThenInclude, or projection Select to DTO, or AsSplitQuery() when cartesian explosion hurts.
Detailed answer
Enable sensitive logging / ToQueryString / MiniProfiler. Symptom: 1 query for orders + N for items. Fix: Include/ThenInclude, or projection Select to DTO, or AsSplitQuery() when cartesian explosion hurts. Prefer AsNoTracking for reads. Add indexes on FK.
Real example & use case
GET /orders?include=items uses .Include(o => o.Items).AsNoTracking().
Pros & cons
Pros: fewer round trips. Cons: over-Include can over-fetch.
#efcore#sql#performance