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fix: critical memory leak from per-session database connections (#554)

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* fix: critical memory leak from per-session database connections (#542)

Each MCP session was creating its own database connection (~900MB),
causing OOM kills every ~20 minutes with 3-4 concurrent sessions.

Changes:
- Add SharedDatabase singleton pattern - all sessions share ONE connection
- Reduce session timeout from 30 min to 5 min (configurable)
- Add eager cleanup for reconnecting instances
- Fix telemetry event listener leak

Memory impact: ~900MB/session → ~68MB shared + ~5MB/session overhead

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
Conceived by Romuald Czlonkowski - https://www.aiadvisors.pl/en

* fix: resolve test failures from shared database race conditions

- Fix `shutdown()` to respect shared database pattern (was directly closing)
- Add `await this.initialized` in both `close()` and `shutdown()` to prevent
  race condition where cleanup runs while initialization is in progress
- Add double-shutdown protection with `isShutdown` flag
- Export `SharedDatabaseState` type for proper typing
- Include error details in debug logs
- Add MCP server close to `shutdown()` for consistency with `close()`
- Null out `earlyLogger` in `shutdown()` for consistency

The CI test failure "The database connection is not open" was caused by:
1. `shutdown()` directly calling `this.db.close()` which closed the SHARED
   database connection, breaking subsequent tests
2. Race condition where `shutdown()` ran before initialization completed

Conceived by Romuald Członkowski - www.aiadvisors.pl/en

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

* test: add unit tests for shared-database module

Add comprehensive unit tests covering:
- getSharedDatabase: initialization, reuse, different path error, concurrent requests
- releaseSharedDatabase: refCount decrement, double-release guard
- closeSharedDatabase: state clearing, error handling, re-initialization
- Helper functions: isSharedDatabaseInitialized, getSharedDatabaseRefCount

21 tests covering the singleton database connection pattern used to prevent
~900MB memory leaks per session.

Conceived by Romuald Członkowski - www.aiadvisors.pl/en

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
This commit is contained in:
Romuald Członkowski
2026-01-23 19:51:22 +01:00
committed by GitHub
parent fad3437977
commit c8c76e435d
9 changed files with 761 additions and 45 deletions
Download Patch File Download Diff File Expand all files Collapse all files

18
tests/unit/http-server-session-management.test.ts
View File

@@ -333,13 +333,14 @@ describe('HTTP Server Session Management', () => {
server = new SingleSessionHTTPServer();
// Mock expired sessions
// Note: Default session timeout is 5 minutes (configurable via SESSION_TIMEOUT_MINUTES)
const mockSessionMetadata = {
'session-1': {
lastAccess: new Date(Date.now() - 40 * 60 * 1000), // 40 minutes ago (expired)
'session-1': {
lastAccess: new Date(Date.now() - 10 * 60 * 1000), // 10 minutes ago (expired with 5 min timeout)
createdAt: new Date(Date.now() - 60 * 60 * 1000)
},
'session-2': {
lastAccess: new Date(Date.now() - 10 * 60 * 1000), // 10 minutes ago (not expired)
'session-2': {
lastAccess: new Date(Date.now() - 2 * 60 * 1000), // 2 minutes ago (not expired with 5 min timeout)
createdAt: new Date(Date.now() - 20 * 60 * 1000)
}
};
@@ -514,15 +515,16 @@ describe('HTTP Server Session Management', () => {
it('should get session metrics correctly', async () => {
server = new SingleSessionHTTPServer();
// Note: Default session timeout is 5 minutes (configurable via SESSION_TIMEOUT_MINUTES)
const now = Date.now();
(server as any).sessionMetadata = {
'active-session': {
lastAccess: new Date(now - 10 * 60 * 1000), // 10 minutes ago
lastAccess: new Date(now - 2 * 60 * 1000), // 2 minutes ago (not expired with 5 min timeout)
createdAt: new Date(now - 20 * 60 * 1000)
},
'expired-session': {
lastAccess: new Date(now - 40 * 60 * 1000), // 40 minutes ago (expired)
lastAccess: new Date(now - 10 * 60 * 1000), // 10 minutes ago (expired with 5 min timeout)
createdAt: new Date(now - 60 * 60 * 1000)
}
};
@@ -532,7 +534,7 @@ describe('HTTP Server Session Management', () => {
};
const metrics = (server as any).getSessionMetrics();
expect(metrics.totalSessions).toBe(2);
expect(metrics.activeSessions).toBe(2);
expect(metrics.expiredSessions).toBe(1);