RavenDB C# client throws error as Invalid node tag character: n - ravendb

Question

I am trying to remove a document in RavenDB which has 3 nodes running in a single machine (development setup).
Below is the code for removing the document.
public bool Remove<T>(string id) where T : new()
{
bool bResult = false;
using (var session = _session.OpenSession())
{
session.Delete(id);
session.SaveChanges();
bResult = true;
}
return bResult;
}
but it throws error on the line session.SaveChanges();
Invalid node tag character: n ...
Stack trace:
System.ArgumentException: Invalid node tag character: n
at Raven.Server.Documents.Replication.ChangeVectorParser.ThrowInvalidNodeTag(Char ch) in C:\Builds\RavenDB-Stable-4.1\src\Raven.Server\Documents\Replication\ChangeVectorParser.cs:line 71
at Raven.Server.Documents.Replication.ChangeVectorParser.ParseNodeTag(String changeVector, Int32 start, Int32 end) in C:\Builds\RavenDB-Stable-4.1\src\Raven.Server\Documents\Replication\ChangeVectorParser.cs:line 52
at Raven.Server.Documents.Replication.ChangeVectorParser.MergeChangeVector(String changeVector, List`1 entries) in C:\Builds\RavenDB-Stable-4.1\src\Raven.Server\Documents\Replication\ChangeVectorParser.cs:line 186
at Raven.Server.Utils.ChangeVectorUtils.MergeVectors(String vectorAstring, String vectorBstring) in C:\Builds\RavenDB-Stable-4.1\src\Raven.Server\Utils\ChangeVectorUtils.cs:line 213
at Raven.Server.Documents.DocumentsStorage.CreateTombstone(DocumentsOperationContext context, Slice lowerId, Int64 documentEtag, CollectionName collectionName, String docChangeVector, Int64 lastModifiedTicks, String changeVector, DocumentFlags flags, NonPersistentDocumentFlags nonPersistentFlags) in C:\Builds\RavenDB-Stable-4.1\src\Raven.Server\Documents\DocumentsStorage.cs:line 1378
at Raven.Server.Documents.DocumentsStorage.Delete(DocumentsOperationContext context, Slice lowerId, String id, LazyStringValue expectedChangeVector, Nullable`1 lastModifiedTicks, String changeVector, CollectionName collectionName, NonPersistentDocumentFlags nonPersistentFlags, DocumentFlags documentFlags) in C:\Builds\RavenDB-Stable-4.1\src\Raven.Server\Documents\DocumentsStorage.cs:line 1195
at Raven.Server.Documents.DocumentsStorage.Delete(DocumentsOperationContext context, String id, String expectedChangeVector) in C:\Builds\RavenDB-Stable-4.1\src\Raven.Server\Documents\DocumentsStorage.cs:line 1091
at Raven.Server.Documents.Handlers.BatchHandler.MergedBatchCommand.ExecuteCmd(DocumentsOperationContext context) in C:\Builds\RavenDB-Stable-4.1\src\Raven.Server\Documents\Handlers\BatchHandler.cs:line 706
at Raven.Server.Documents.TransactionOperationsMerger.ExecutePendingOperationsInTransaction(List`1 pendingOps, DocumentsOperationContext context, Task previousOperation, DurationMeasurement& meter) in C:\Builds\RavenDB-Stable-4.1\src\Raven.Server\Documents\TransactionOperationsMerger.cs:line 825
at Raven.Server.Documents.TransactionOperationsMerger.MergeTransactionsOnce() in C:\Builds\RavenDB-Stable-4.1\src\Raven.Server\Documents\TransactionOperationsMerger.cs:line 500
--- End of stack trace from previous location where exception was thrown ---
at Raven.Server.Documents.TransactionOperationsMerger.Enqueue(MergedTransactionCommand cmd) in C:\Builds\RavenDB-Stable-4.1\src\Raven.Server\Documents\TransactionOperationsMerger.cs:line 124
at Raven.Server.Documents.Handlers.BatchHandler.BulkDocs() in C:\Builds\RavenDB-Stable-4.1\src\Raven.Server\Documents\Handlers\BatchHandler.cs:line 96
at Raven.Server.Routing.RequestRouter.HandlePath(RequestHandlerContext reqCtx) in C:\Builds\RavenDB-Stable-4.1\src\Raven.Server\Routing\RequestRouter.cs:line 124
at Raven.Server.RavenServerStartup.RequestHandler(HttpContext context) in C:\Builds\RavenDB-Stable-4.1\src\Raven.Server\RavenServerStartup.cs:line 172

Answer 1

I've run into the same error yesterday. I restored database on the different machine where I installed brand new RavenDB and (being lazy) named new instance node "A". It appears that RavenDB cannot currently remove documents when change vector and instance tag name don't match.
node-tag-mismatch
It looks like an honest mistake in code instead of intentional behavior.. but its only my guess, because I didn't find anything about this behavior in 4.1 documentation.
Solution (if you confirm there is a mismatch):
You could try to add a new node to your cluster with the name matching change vector of locked documents.
In my case I am not able to configure standalone RavenDB to have node tag of more than 4 characters (that was no problem on Docker)... It might be harder to get database to consistent state then.
Alternatively try exporting and importing data. It fixes the problem because change vectors are updated and match new node tag.