ef-core-query-optimizer

EF Core Query Optimizer

Find and fix the performance problems in Entity Framework Core queries, then return the optimized code with a short explanation of every change.

Input — point it at your code

You don't need pasted snippets. Work directly from whatever target the user gives:

• A single file — path/to/Query.cs
• A folder — path/to/Features/ (scan everything relevant under it)
• A whole project or solution — a .csproj / .sln or the repo root
• A GitHub URL — clone first, then scan: git clone --depth 1 <url> /tmp/repo && cd /tmp/repo

Discover the EF code yourself with Glob/Grep/Bash instead of asking for a paste. Locate candidates first, e.g.:

grep -rl "DbContext\|IQueryable" --include=*.cs <target> | grep -vi "/obj/\|/bin/"
grep -rn "\.Include(\|\.ToListAsync\|\.Where(\|\.Select(\|AsNoTracking" --include=*.cs <target>

On a large project, scan the matched files, prioritize the worst offenders, and don't read unrelated code. Always tell the user which files you scanned and group findings by file.

When this runs

The user has shared EF Core code (queries, a DbContext, repositories, services) or a project/repo and wants it faster or reviewed. They may give a path, a folder, a solution, or a GitHub link — scan it yourself. Only ask for more if the target has no EF code or you need the entity/DbContext configuration to confirm a fix.

Workflow

1. Read the code and the data shape. Identify the entities, relationships (1:1, 1:many, many:many), and what the query actually needs to return.
2. Run the checklist below against every query.
3. Rewrite the problematic queries. Keep behavior identical unless a bug is found (call out bugs separately).
4. Explain each change in one line — what was wrong, why it's slow, what the fix does.
5. Flag what you cannot verify (e.g. missing indexes need the DB schema; suggest the migration but mark it as "verify").

The checklist

Apply every item. For each finding, state the problem, the impact, and the fix.