[Enhancement]: Auto-fallback to SQLite for zero-config startup when embedded seekdb is unavailable (non-Linux / missing pylibseekdb)

[knqiufan]

Description

PR #393 made embedded seekdb the zero-config default (DATABASE_PROVIDER=oceanbase, empty OCEANBASE_HOST → ./seekdb_data). This works on Linux where pylibseekdb is available, but on Windows/macOS the same path fails with pylibseekdb is not available (Linux only). powermem-server still starts and /api/v1/system/health returns healthy, while all memory APIs return 503 because MemoryService init fails — a confusing experience for Claude Code / VS Code / Dashboard users on non-Linux platforms.

Proposal: When storage is not explicitly configured, auto-select the default provider:

• DATABASE_PROVIDER or OCEANBASE_HOST set → respect user config (unchanged).
• Non-Linux → default to sqlite (SQLITE_PATH=./data/powermem_dev.db), log INFO.
• Linux → probe pylibseekdb; if available keep embedded seekdb; otherwise fall back to sqlite with WARNING.

This completes PR #393's zero-config goal on cross-platform dev machines without changing the Linux default. Centralize logic in a shared helper (e.g. default_database_provider()). Workaround today: manual .env with DATABASE_PROVIDER=sqlite (see apps/claude-code-plugin/SETUP.md [E005]).

Willing to submit a PR after acceptance.

[longdafeng]

Doesn't seekdb works on macOS? I remember seekdb works on my macOS

[lightzt99]

Hi @knqiufan, thanks for the detailed report. Could you help us narrow down the scope?

• What is your Mac's chip type? (Intel x86_64 or Apple Silicon arm64)
• What version of pylibseekdb was installed when you hit the issue?

[knqiufan]

@lightzt99 @longdafeng Thanks for the feedback! I think I should clarify my intent,the original description may have been a bit broad.

I believe SeekDB works fine on macOS. My issue is specifically about Windows. My environment is Windows 10 x86_64. I didn't hit this on Mac. Apologies for the imprecise scope.

The core scenario I encountered: When starting powermem from source on Windows, the default config uses embedded SeekDB, but SeekDB doesn't ship a Windows build. This causes MemoryService init to fail silently, the server starts, health check passes, but all memory APIs return 503. This is a confusing experience, especially for new users.

My proposal is mainly about graceful degradation on Windows (not questioning SeekDB's macOS support, apologies for the confusion). The idea is: when SeekDB is genuinely unavailable, auto-fall back to SQLite instead of failing silently, and show a clear indicator on the Dashboard so the user knows they're running on SQLite.

That said, I'm aware this introduces another concern: if a user has been running with SeekDB for a while and SeekDB becomes unavailable for some reason (e.g. a broken upgrade), the system would silently switch to a fresh SQLite database — causing a memory gap without the user realizing it. This is something worth discussing before merging.

Happy to narrow the PR scope or adjust the approach based on your thoughts.