* 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>
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Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
