[MEDIUM] Large database queries without pagination

[Tsukieomie]

Performance Issue: Unpaginated Database Queries

Severity: MEDIUM
Location: src/main/lib/trpc/routers/files.ts:222-253

Description

File scanning reads entire directory tree without pagination, potentially causing memory spikes on large projects.

Risk

• Large projects (node_modules, .git) could cause memory issues
• No timeout on directory traversal
• Simple 5-second TTL cache may not be sufficient

Current Mitigation

• Traversal depth limit: 15 (good ✓)
• File type filtering (good ✓)
• Basic caching (needs improvement)

Recommendation

1. Add Pagination

interface FileListOptions {
  limit?: number
  offset?: number
  maxFiles?: number  // Hard limit
}

// Stop after maxFiles reached
if (results.length >= maxFiles) break

2. Add Timeout/Cancellation

const abortController = new AbortController()
const timeout = setTimeout(() => abortController.abort(), 5000)

// Check abort signal during traversal
if (abortController.signal.aborted) break

3. Improve Caching Strategy

• LRU cache with size limit
• Invalidate on file system changes (use chokidar)
• Per-directory caching instead of full tree

4. Stream Results

// Instead of returning all at once
for await (const file of walkDirectory()) {
  yield file  // Stream to client
}

Impact

Medium - Affects performance on large codebases, could cause app to freeze.

Labels: performance, database