Postgres perf, path migration, and shutdown race fixes

- Major query performance boost: replaced correlated subqueries with DistinctBy() in BaseItemRepository, added episode deduplication index, and increased default command timeout to 120s. - Fixed LibraryMonitor shutdown race: added disposal checks and exception handling in FileRefresher to prevent ObjectDisposedException. - Added PowerShell and SQL utilities for fixing Linux paths in config files and database; new scripts for WebDir and path migration. - Auto-fix for WebDir in startup.json on load; new helper scripts and docs. - Added automated weekly DB performance monitoring scripts and reporting. - Expanded documentation and README for all fixes, scripts, and migration steps. - Updated SQL scripts for index creation and diagnostics; improved output handling. - Updated db-config defaults and added new diagnostic/report files.
2026-03-05 08:56:42 -05:00
parent 0eb44818ff
commit 7eb2b445cb
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+# LibraryMonitor Disposal Fix - Summary
+
+## What Was Fixed
+
+Fixed `ObjectDisposedException` that occurred during application shutdown when file system monitor timer callbacks executed after the service provider was disposed.
+
+## Error Message
+
+```
+System.ObjectDisposedException: Cannot access a disposed object.
+Object name: 'IServiceProvider'.
+   at Emby.Server.Implementations.IO.LibraryMonitor: Error processing directory changes
+```
+
+## Root Cause
+
+Race condition during shutdown:
+1. Application begins shutdown and disposes `IServiceProvider`
+2. `LibraryMonitor` disposal starts
+3. `FileRefresher` timer callback fires **before** timer is fully disposed
+4. Callback tries to access database through disposed service provider
+5. Exception thrown
+
+## Solution
+
+Added three layers of protection in `FileRefresher.cs`:
+
+### 1. Early Exit Check
+```csharp
+private void OnTimerCallback(object? state)
+{
+    if (_disposed) return; // ← Added
+    // ...
+}
+```
+
+### 2. Post-Timer-Disposal Check
+```csharp
+DisposeTimer();
+if (_disposed) return; // ← Added
+ProcessPathChanges(paths);
+```
+
+### 3. Exception Handling
+```csharp
+try
+{
+    itemsToRefresh = paths.Select(GetAffectedBaseItem)...;
+}
+catch (ObjectDisposedException) // ← Added
+{
+    _logger.LogDebug("Service provider disposed during shutdown");
+    return;
+}
+```
+
+## Impact
+
+- ✅ Clean application shutdowns
+- ✅ No more `ObjectDisposedException` errors in logs
+- ✅ No impact on normal operation
+- ✅ Graceful handling of shutdown race conditions
+
+## Files Modified
+
+- **Emby.Server.Implementations\IO\FileRefresher.cs**
+  - Added disposal checks in `OnTimerCallback`
+  - Added disposal handling in `ProcessPathChanges`
+
+## Testing
+
+- ✅ Build successful
+- ✅ No breaking changes
+- ✅ Addresses shutdown race condition
+
+## Documentation
+
+- **Full Guide:** [LIBRARYMONITOR_DISPOSAL_FIX.md](./LIBRARYMONITOR_DISPOSAL_FIX.md)
+- **README Updated:** Added to "Error Fixes & Troubleshooting" section
+
+## Related Issues
+
+This error typically appears when:
+- Application is shutting down
+- File system changes occur during shutdown
+- Timer callbacks execute after service disposal begins
+
+The fix ensures these scenarios are handled gracefully.
+
+---
+
+**Status:** ✅ Complete  
+**Risk Level:** Low (shutdown-only scenario)  
+**User Impact:** Reduced error noise in logs during shutdown