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perf: progressive loading for Cursor vscdb sessions #125

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Merged
vakovalskii merged 1 commit into from
Apr 8, 2026
Merged

perf: progressive loading for Cursor vscdb sessions #125

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183 changes: 119 additions & 64 deletions src/data.js
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Original file line number Diff line number Diff line change
Expand Up @@ -570,16 +570,26 @@ function decodeCursorProjectFolderKey(proj) {
return cwd;
}

// Build composerId -> project path mapping from Cursor workspace storage (cached 5 min)
// Build composerId -> project path mapping from Cursor workspace storage
// Uses disk cache to avoid querying 190+ SQLite files on every startup
let _cursorWsMapCache = null;
let _cursorWsMapCacheTs = 0;
const CURSOR_WS_MAP_TTL = 300000; // 5 minutes
const CURSOR_WS_MAP_CACHE_FILE = path.join(os.tmpdir(), 'codedash-cursor-ws-map.json');
const CURSOR_WS_MAP_TTL = 600000; // 10 minutes

function buildCursorWorkspaceMap() {
const now = Date.now();
if (_cursorWsMapCache && (now - _cursorWsMapCacheTs) < CURSOR_WS_MAP_TTL) {
return _cursorWsMapCache;
}
if (_cursorWsMapCache) return _cursorWsMapCache;

// Try loading from disk cache first (~1ms vs ~1500ms full rebuild)
try {
if (fs.existsSync(CURSOR_WS_MAP_CACHE_FILE)) {
const cached = JSON.parse(fs.readFileSync(CURSOR_WS_MAP_CACHE_FILE, 'utf8'));
if (cached._ts && (Date.now() - cached._ts) < CURSOR_WS_MAP_TTL) {
delete cached._ts;
_cursorWsMapCache = cached;
return cached;
}
}
} catch {}

const map = {}; // composerId -> projectPath
if (!fs.existsSync(CURSOR_WORKSPACE_STORAGE)) return map;
Expand Down Expand Up @@ -621,7 +631,12 @@ function buildCursorWorkspaceMap() {
} catch {}

_cursorWsMapCache = map;
_cursorWsMapCacheTs = now;

// Save to disk cache for fast startup next time
try {
fs.writeFileSync(CURSOR_WS_MAP_CACHE_FILE, JSON.stringify(Object.assign({ _ts: Date.now() }, map)));
} catch {}

return map;
}

Expand Down Expand Up @@ -733,62 +748,8 @@ function scanCursorSessions() {
} catch {}
}

// Scan Cursor global state.vscdb (composerData + bubbleId entries)
if (fs.existsSync(CURSOR_GLOBAL_DB)) {
try {
// Build workspace -> project mapping for project association
const wsMap = buildCursorWorkspaceMap();

// Use json_extract + json_array_length for lightweight query (~215KB vs ~48MB full values)
const rows = execFileSync('sqlite3', [
'-separator', '\t',
CURSOR_GLOBAL_DB,
"SELECT json_extract(value, '$.composerId'), json_extract(value, '$.name'), json_extract(value, '$.createdAt'), json_extract(value, '$.lastUpdatedAt'), json_array_length(json_extract(value, '$.fullConversationHeadersOnly')) FROM cursorDiskKV WHERE key LIKE 'composerData:%'"
], { encoding: 'utf8', timeout: 15000, maxBuffer: 10 * 1024 * 1024, windowsHide: true }).trim();

if (rows) {
for (const row of rows.split('\n')) {
const cols = row.split('\t');
if (cols.length < 5) continue;

try {
const composerId = cols[0];
if (!composerId || seenIds.has(composerId)) continue;

const name = cols[1] || '';
const createdAt = parseInt(cols[2]) || 0;
const lastUpdatedAt = parseInt(cols[3]) || createdAt;
const msgCount = parseInt(cols[4]) || 0;

// Skip empty sessions (no messages at all)
if (msgCount === 0) continue;

// Get first user message text from the session name (Cursor auto-names sessions)
const firstMsg = name.slice(0, 200);

// Resolve project path from workspace mapping
const projectPath = wsMap[composerId] || '';

seenIds.add(composerId);
sessions.push({
id: composerId,
tool: 'cursor',
project: projectPath,
project_short: projectPath ? projectPath.replace(os.homedir(), '~') : '',
first_ts: createdAt,
last_ts: lastUpdatedAt,
messages: msgCount,
first_message: firstMsg,
has_detail: true,
file_size: 0,
detail_messages: msgCount,
_cursor_vscdb: true,
});
} catch {}
}
}
} catch {}
}
// Cursor vscdb sessions are loaded via background task (see _loadCursorVscdbInBackground)
// and merged into loadSessions() result when ready

return sessions;
}
Expand Down Expand Up @@ -1171,6 +1132,86 @@ let _sessionsCache = null;
let _sessionsCacheTs = 0;
const SESSIONS_CACHE_TTL = 10000; // 10 seconds

// Progressive loading: cursor vscdb sessions load in background
let _cursorVscdbSessions = null;
let _cursorVscdbLoading = false;

function _loadCursorVscdbInBackground() {
if (_cursorVscdbLoading || _cursorVscdbSessions) return;
if (!fs.existsSync(CURSOR_GLOBAL_DB)) { _cursorVscdbSessions = []; return; }
_cursorVscdbLoading = true;

// Workspace map from disk cache is instant (~1ms), only global DB query is slow
const wsMap = buildCursorWorkspaceMap();
const homedir = os.homedir();

// Async sqlite3 query — does NOT block the event loop
const query = "SELECT json_extract(value, '$.composerId'), json_extract(value, '$.name'), json_extract(value, '$.createdAt'), json_extract(value, '$.lastUpdatedAt'), json_array_length(json_extract(value, '$.fullConversationHeadersOnly')) FROM cursorDiskKV WHERE key LIKE 'composerData:%'";

const child = require('child_process').execFile('sqlite3', [
'-separator', '\t', CURSOR_GLOBAL_DB, query
], { encoding: 'utf8', timeout: 15000, maxBuffer: 10 * 1024 * 1024, windowsHide: true },
function(err, stdout) {
try {
const results = [];
const rows = (stdout || '').trim();
if (rows) {
for (const row of rows.split('\n')) {
const cols = row.split('\t');
if (cols.length < 5) continue;
const composerId = cols[0];
if (!composerId) continue;
const msgCount = parseInt(cols[4]) || 0;
if (msgCount === 0) continue;
const projectPath = wsMap[composerId] || '';
results.push({
id: composerId,
tool: 'cursor',
project: projectPath,
project_short: projectPath ? projectPath.replace(homedir, '~') : '',
first_ts: parseInt(cols[2]) || 0,
last_ts: parseInt(cols[3]) || parseInt(cols[2]) || 0,
messages: msgCount,
first_message: (cols[1] || '').slice(0, 200),
has_detail: true,
file_size: 0,
detail_messages: msgCount,
_cursor_vscdb: true,
});
}
}
_cursorVscdbSessions = results;
} catch {
_cursorVscdbSessions = [];
}
_cursorVscdbLoading = false;
// Merge into existing cache instead of full invalidation
if (_sessionsCache && _cursorVscdbSessions && _cursorVscdbSessions.length > 0) {
const existingIds = new Set(_sessionsCache.map(function(s) { return s.id; }));
const newSessions = [];
for (var i = 0; i < _cursorVscdbSessions.length; i++) {
var cs = _cursorVscdbSessions[i];
if (existingIds.has(cs.id)) continue;
cs.first_time = new Date(cs.first_ts).toLocaleString('sv-SE').slice(0, 16);
cs.last_time = new Date(cs.last_ts).toLocaleString('sv-SE').slice(0, 16);
var dt = new Date(cs.last_ts);
cs.date = dt.getFullYear() + '-' + String(dt.getMonth()+1).padStart(2,'0') + '-' + String(dt.getDate()).padStart(2,'0');
cs.git_root = '';
if (!cs.mcp_servers) cs.mcp_servers = [];
if (!cs.skills) cs.skills = [];
newSessions.push(cs);
}
if (newSessions.length > 0) {
_sessionsCache = _sessionsCache.concat(newSessions).sort(function(a, b) { return b.last_ts - a.last_ts; });
// Keep the same cache timestamp — no full rebuild needed
}
} else {
_sessionsCache = null;
_sessionsCacheTs = 0;
}
});
}

function loadSessions() {
const now = Date.now();
if (_sessionsCache && (now - _sessionsCacheTs) < SESSIONS_CACHE_TTL) {
Expand Down Expand Up @@ -1399,6 +1440,17 @@ function loadSessions() {
if (!s.skills) s.skills = [];
}

// Merge background-loaded Cursor vscdb sessions (progressive loading)
const existingIds = new Set(Object.keys(sessions));
if (_cursorVscdbSessions) {
for (const cs of _cursorVscdbSessions) {
if (!existingIds.has(cs.id)) sessions[cs.id] = cs;
}
} else {
// Kick off background loading if not started yet
_loadCursorVscdbInBackground();
}

const result = Object.values(sessions).sort((a, b) => b.last_ts - a.last_ts);

// Collect unique project paths and resolve git roots in one pass
Expand All @@ -1414,6 +1466,9 @@ function loadSessions() {
s.git_root = s.worktree_original_cwd || (s.project ? (_gitRootCache[s.project] || '') : '');
}

// Flag for frontend: true = cursor vscdb still loading, will have more data soon
result._loading = !_cursorVscdbSessions && _cursorVscdbLoading;

_sessionsCache = result;
_sessionsCacheTs = Date.now();
return result;
Expand Down
4 changes: 4 additions & 0 deletions src/frontend/app.js
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Original file line number Diff line number Diff line change
Expand Up @@ -390,6 +390,10 @@ async function loadSessions() {
var resp = await fetch('/api/sessions');
allSessions = await resp.json();
applyFilters();
// Progressive loading: if server is still loading cursor vscdb sessions, auto-refresh
if (resp.headers.get('X-Loading') === '1') {
setTimeout(loadSessions, 2000);
}
} catch (e) {
document.getElementById('content').innerHTML = '<div class="empty-state">Failed to load sessions. Is the server running?</div>';
}
Expand Down
4 changes: 3 additions & 1 deletion src/server.js
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Original file line number Diff line number Diff line change
Expand Up @@ -68,7 +68,9 @@ function startServer(host, port, openBrowser = true) {
const sessions = loadSessions();
const byTool = {};
sessions.forEach(s => { byTool[s.tool] = (byTool[s.tool] || 0) + 1; });
log('DATA', `loaded ${sessions.length} sessions`, byTool);
log('DATA', `loaded ${sessions.length} sessions${sessions._loading ? ' (cursor loading...)' : ''}`, byTool);
// Send _loading flag as header to avoid polluting array response
if (sessions._loading) res.setHeader('X-Loading', '1');
json(res, sessions);
}

Expand Down
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