Settings and app data
DuckLocal keeps one file on disk. Everything else lives in memory for the duration of a session.
Where things are stored
| Platform | Path |
|---|---|
| macOS | ~/Library/Application Support/DuckLocal/history.duckdb |
| Linux (if built there) | ~/.local/share/ducklocal/history.duckdb |
That single DuckDB file holds three tables: the query history, the registered data files, and a small key/value settings table — the interface language, the open app and dashboard tabs, the recent-documents list, and the app folders you have trusted. It lives beside a .wal while the app is running.
Your data is never copied into it. Registered files are referenced by path and re-attached on launch.
What survives a restart
| Remembered | Where |
|---|---|
| Registered data files — path, view name, kind | app data file |
| Query history, including failures | app data file |
| Interface language | app data file |
| Interface size | app data file |
| Whether the sidebar is hidden | app data file |
| Open app and dashboard tabs, with their titles | app data file |
| Recently opened apps and dashboards (the sidebar's Apps / Dashboards) | app data file |
| App folders you chose to trust | app data file |
| Not remembered | Notes |
|---|---|
| Open query tabs and their SQL | in memory only — past queries are in History |
| The results panel contents | in memory only |
| Which database file is open | each launch starts in memory unless you name one |
| Window size and position | fixed at 1440×900, minimum 960×600 |
| Sidebar and results panel sizes | fixed per launch |
| The results filter | in memory only |
| The theme | always starts light — see below |
| S3 credentials | session-only by design |
The theme is the odd one out: the language toggle persists, the theme toggle does not, and every launch begins in light mode.
Language
The EN / 中 button in the title bar switches the interface language immediately and records the choice.
On first run — before any setting is stored — the language is taken from the system locale: LC_ALL or LANG containing zh selects Chinese, anything else selects English. An unrecognized stored value falls back to Chinese.
A few strings are deliberately not translated: DuckLocal, the S3 and EXPLAIN button labels, the EN / 中 toggle, and the credential placeholders. Engine and network error messages are surfaced verbatim and are always in English, whatever the interface language is.
Themes
The sun/moon button toggles between the light and dark theme. There is no theme picker and no theme file to edit — the two modes are what you get.
Interface size
Text, icons and controls scale together, in four steps:
| Size | Base text | Editor text |
|---|---|---|
| Small | 13px | 12px |
| Default | 14px | 13px |
| Large | 16px | 15px |
| Extra large | 18px | 17px |
Choose one from the Aa button in the title bar, or step through them with ⌘+ (larger), ⌘− (smaller) and ⌘0 (back to default) — these work wherever the focus is, the SQL editor included. The choice is remembered, and survives switching between light and dark.
Panel sizes you dragged, and the height of a dashboard's plots, stay in pixels: they are yours to adjust, not the interface's.
Resetting
To start over — clearing history, registered files, remembered tabs, trusted app folders and the language setting — quit DuckLocal and remove its app data directory:
rm -rf ~/Library/Application\ Support/DuckLocalThe next launch creates it fresh. Your data files are never affected by this, only DuckLocal's own records.
Troubleshooting
Symptoms, causes and fixes are collected on the Troubleshooting page.