Report: High Memory Usage in Large Workspaces

Issue Description

VS Code was consuming excessive memory (4GB+) when opening large monorepo workspaces with more than 20 TypeScript projects. This caused performance degradation and sometimes crashes on machines with limited RAM.

Investigation

• Profiled memory usage using Chrome DevTools
• Identified that the TypeScript language server was creating separate instances for each project
• Found that file watchers were duplicating efforts across projects
• Discovered unnecessary caching of AST nodes

Reproduction Steps

1. Open a monorepo with 20+ TypeScript projects
2. Wait for IntelliSense to initialize
3. Observe memory usage climbing above 4GB
4. Notice sluggish editor performance

Impact

• Affected developers working on large codebases
• Made VS Code unusable on lower-end machines
• Caused crashes during long coding sessions

Resolution

The VS Code team implemented several optimizations:

• Shared TypeScript server instances across related projects
• Optimized file watcher strategy
• Improved AST node caching with LRU eviction

Issue Thread

#144523 - Closed as fixed on January 5, 2026