[BUG] Database Doesn't Enable WAL Mode

[olddev94]

Project

vgrep

Description

The SQLite database in src/core/db.rs is opened without enabling WAL (Write-Ahead Logging) mode. This can cause concurrency issues when multiple processes access the database simultaneously (e.g., watcher + search) and reduces write performance.

Error Message

Error: database is locked

or

SQLITE_BUSY

Debug Logs

System Information

- Bounty Version: 0.1.0
- OS: Ubuntu 24.04 LTS
- Rust: 1.75+

Screenshots

No response

Steps to Reproduce

1. Start the watcher in one terminal: vgrep watch
2. Run searches in another terminal: vgrep search "query"
3. Modify files while searching
4. Observe occasional "database is locked" errors

Expected Behavior

The database should:

1. Enable WAL mode for better concurrency
2. Set a busy timeout to handle lock contention gracefully
3. Potentially set synchronous mode for performance

Actual Behavior

1. Uses default DELETE journal mode
2. No busy timeout (immediate SQLITE_BUSY on contention)
3. Writers block readers and vice versa
4. Suboptimal write performance

Additional Context

WAL mode benefits:

• Readers don't block writers
• Writers don't block readers
• Better write performance (commits can overlap)
• Crash recovery is more robust

The issue manifests when:

• File watcher is running while user searches
• Server handles multiple simultaneous requests
• Index operation runs while search occurs

Without WAL mode, SQLite uses rollback journal which requires exclusive locks for writes, causing blocking.

[echobt]

Issue validated. The reported problem has been confirmed in the codebase. A Pull Request with the fix has been submitted: CortexLM/vgrep#31.