Problem

OpenClaw gateway loads ALL session files into memory at startup:

1. sessions.json (42MB in our case) is loaded via readFileSync + JSON.parse
2. All JSONL session files (831 files, 389MB) are loaded via readFileSync per session access
3. No lazy loading or streaming mechanism exists

This causes the gateway process to consume 3.5GB+ RSS on a 16GB machine after running for a few weeks.

Impact

• Gateway RSS grows linearly with session history
• No pagination or streaming for session messages
• sessions.json is a single 42MB file that gets parsed entirely on every access
• Memory never shrinks because V8 GC is not aggressive enough

Environment

• OpenClaw version: latest
• OS: macOS (ARM64)
• Session count: 831 files
• sessions.json size: 42MB

Suggested Fix

1. Lazy-load session JSONL files only when needed
2. Stream/paginate session messages instead of readFileSync
3. Split sessions.json into per-session metadata files
4. Add configurable memory limits
5. Implement LRU cache for active sessions only