Optimizing EF Core Queries

Diagnose and fix slow or incorrect application data access built on EF Core. In a source-only review, trace the code without executing it and separate proven code behavior from runtime assumptions. When SQL, logs, or plans are available, use them to confirm the bottleneck. Prefer changes that reduce round-trips, duplicated rows, scans, or per-call translation cost over micro-optimizations.

When to Use

• EF Core queries are slow or emit far more SQL statements than expected
• The same query repeats once per row (N+1 / lazy loading)
• Multiple collection Includes blow up or duplicate rows
• Deep pages slow down as Skip grows, or bulk updates load rows just to modify them
• A filtered/sorted query scans even though the column is indexed, or a filtered/sorted column has no supporting index
• A hot, frequently-executed query pays EF Core's LINQ-translation cost on every call

When Not to Use

• The code uses Dapper or raw ADO.NET, not EF Core. Answer the SQL/indexing/query-plan question directly; do not introduce a DbContext or recommend AsNoTracking, Include, AsSplitQuery, or other EF Core APIs.

Source review workflow