add a toggle to filter empty schemas and db

[Light2Dark]

📝 Summary

Closes #6807.

This toggles empty db and schemas. By default all are shown, this config is stored in local storage.

Screen.Recording.2026-05-28.at.5.35.47.PM.mov

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Project	Deployment	Actions	Updated (UTC)
marimo-docs	Ready	Preview, Comment	May 28, 2026 9:36am

[cubic-dev-ai]

1 issue found across 3 files

Prompt for AI agents (unresolved issues)

Check if these issues are valid — if so, understand the root cause of each and fix them. If appropriate, use sub-agents to investigate and fix each issue separately.


<file name="frontend/src/components/datasources/datasources.tsx">

<violation number="1" location="frontend/src/components/datasources/datasources.tsx:156">
P1: The new empty-schema filter treats `tables.length === 0` as definitively empty, but `0` is also the lazy-loading state. This can hide schemas/databases before table fetches run, preventing users from ever loading their tables.</violation>
</file>

Architecture diagram

sequenceDiagram
    participant UI as DataSources Panel
    participant Store as Jotai Store (localStorage)
    participant Backend as Backend API
    participant Cache as React useMemo

    Note over UI,Cache: Initial Load
    
    UI->>Store: NEW: read hideEmptyDatasourcesAtom (from localStorage key "marimo:datasources:hideEmpty")
    Store-->>UI: false (default)

    UI->>Backend: fetch databases & schemas
    Backend-->>UI: rawConnections with all databases & schemas

    Note over UI,Cache: Toggle Filter
    
    UI->>UI: user clicks Eye/EyeOff button
    UI->>Store: NEW: setHideEmpty(!hideEmpty)
    Store-->>UI: confirm toggle

    Note over UI,Cache: Re-render with filter applied
    
    UI->>Cache: NEW: useMemo recomputes dataConnections
    Cache->>Cache: NEW: filterEmptyDatabases() applied per connection
    
    alt hideEmpty === false
        Cache-->>UI: return rawConnections unchanged
    else hideEmpty === true
        Note over Cache: For each connection.databases:
        Cache->>Cache: filter schemas with 0 tables
        Cache->>Cache: filter databases where all schemas are empty
        alt database.schemas.length === 0
            Note over Cache: preserve - lazy state
        end
        Cache-->>UI: filteredConnections
    end

    alt filteredConnections changed
        UI->>UI: re-render tree with filtered data
    else no change (immuatable check)
        UI->>UI: return previous reference
    end

    Note over UI,Backend: Unchanged Backend Behavior
    
    Note over Backend: CHANGED: get_schemas() no longer filters empty schemas server-side
    Note over Backend: now returns ALL schemas regardless of table count

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<sub>Reply with feedback, questions, or to request a fix.

Re-trigger cubic</sub>

[cubic-dev-ai]

P1: The new empty-schema filter treats tables.length === 0 as definitively empty, but 0 is also the lazy-loading state. This can hide schemas/databases before table fetches run, preventing users from ever loading their tables.

Prompt for AI agents

Check if this issue is valid — if so, understand the root cause and fix it. At frontend/src/components/datasources/datasources.tsx, line 156:

<comment>The new empty-schema filter treats `tables.length === 0` as definitively empty, but `0` is also the lazy-loading state. This can hide schemas/databases before table fetches run, preventing users from ever loading their tables.</comment>

<file context>
@@ -116,6 +124,51 @@ const sortedTablesAtom = atom((get) => {
+      continue;
+    }
+    const nonEmptySchemas = database.schemas.filter(
+      (schema) => schema.tables.length > 0,
+    );
+    if (nonEmptySchemas.length === 0) {
</file context>