mongodb data_error ai_generated partial

MongoServerError: orphan documents detected during chunk migration on namespace mydb.mycoll

ID: mongodb/sharded-cluster-orphan-documents

Also available as: JSON · Markdown · 中文

75%Fix Rate

82%Confidence

1Evidence

2024-01-10First Seen

Version Compatibility

Version	Status	Introduced	Deprecated	Notes
MongoDB 6.0	active	—	—	—
MongoDB 7.0	active	—	—	—
MongoDB 8.0	active	—	—	—

Chunk migration left behind documents that do not belong to the new shard range due to concurrent writes or a failed migration cleanup.

generic

由于并发写入或迁移清理失败，块迁移留下了不属于新分片范围的文档。

80% success Use the cleanupOrphaned command on the affected shard to remove orphan documents: db.adminCommand({ cleanupOrphaned: 'mydb.mycoll' }).
```
Use the cleanupOrphaned command on the affected shard to remove orphan documents: db.adminCommand({ cleanupOrphaned: 'mydb.mycoll' }).
```
85% success Temporarily disable the balancer (sh.stopBalancer()) and manually re-migrate the chunk to ensure consistent range coverage.
```
Temporarily disable the balancer (sh.stopBalancer()) and manually re-migrate the chunk to ensure consistent range coverage.
```
70% success Verify shard key distribution and adjust chunk boundaries using splitChunk to isolate orphan documents.
```
Verify shard key distribution and adjust chunk boundaries using splitChunk to isolate orphan documents.
```

Use the cleanupOrphaned command on the affected shard to remove orphan documents: db.adminCommand({ cleanupOrphaned: 'mydb.mycoll' }).

Temporarily disable the balancer (sh.stopBalancer()) and manually re-migrate the chunk to ensure consistent range coverage.

Verify shard key distribution and adjust chunk boundaries using splitChunk to isolate orphan documents.

Common approaches that don't work:

80% fail
Deletion without verifying shard key ranges can cause data loss.
90% fail
Orphans persist after restart unless the balancer re-migrates or cleanup runs.
50% fail
Cleanup may conflict with ongoing balancer operations, requiring repeated runs.