Kusto.Ingest errors and exceptions

Article
08/12/2024

Applies to: ✅ Microsoft Fabric ✅ Azure Data Explorer

Any error during the ingestion handling on the client side is indicated by a C# exception.

Failures

KustoDirectIngestClient exceptions

While attempting to ingest from multiple sources, errors might occur during the ingestion process. If an ingestion fails for one of the sources, it's logged and the client continues to ingest the remaining sources. After going over all sources for ingestion, an IngestClientAggregateException is thrown, containing the IList<IngestClientException> IngestionErrors member.

IngestClientException and its derived classes contain a field IngestionSource and an Error field. The two fields together create a mapping, from the source that failed ingestion, to the error that occurred while attempting the ingestion. The information can be used in the IngestionErrors list to investigate which sources failed ingestion and why. The IngestClientAggregateException exception also contains a boolean property GlobalError, that indicates whether an error occurred for all sources.

Failures ingesting from files or blobs

If an ingestion failure occurs while attempting to ingest from a blob or file, the ingestion sources won't be deleted, even if the deleteSourceOnSuccess flag is set to true. The sources are preserved for further analysis. Once the origin of the error is understood, and if the error didn't originate from the ingestion source itself, then the user of the client may attempt to reingest it.

Failures ingesting from IDataReader

While ingesting from DataReader, the data to ingest is saved to a temporary folder whose default location is <Temp Path>\Ingestions_<current date and time>. This default folder is always deleted after a successful ingestion.

In the IngestFromDataReader and IngestFromDataReaderAsync methods, the retainCsvOnFailure flag, whose default value is false, determines whether the files should be kept after a failed ingestion. If this flag is set to false, data that fails the ingestion won't be persisted, making it hard to understand what went wrong.

KustoQueuedIngestClient exceptions

KustoQueuedIngestClient ingests data by uploading messages to an Azure queue. If an error occurs before or during the queueing process, an IngestClientAggregateException is thrown at the end of the process. The thrown exception includes a collection of IngestClientException, that contains the source of each failure, and hadn't been posted to the queue. The error that occurred while attempting to post the message is also thrown.

Posting to queue failures with a file or blob as a source

If an error occurs while using the KustoQueuedIngestClient's IngestFromFile/IngestFromBlob methods, the sources aren't deleted, even if the deleteSourceOnSuccess flag is set to true. Instead, the sources are preserved for further analysis.

Once the origin of the error is understood, and if the error didn't originate from the ingestion source itself, the user of the client may attempt to requeue the data by using the relevant IngestFromFile/IngestFromBlob methods with the failed source.

Posting to queue failures with IDataReader as a source

While using a DataReader source, the data to post to the queue is saved to a temporary folder whose default location is <Temp Path>\Ingestions_<current date and time>. This folder is always deleted after the data has been successfully posted to the queue. In the IngestFromDataReader and IngestFromDataReaderAsync methods, the retainCsvOnFailure flag, whose default value is false, determines whether the files should be kept after a failed ingestion. If this flag is set to false, data that fails the ingestion won't be persisted, making it hard to understand what went wrong.

Common Failures

Error	Reason	Mitigation
Database <database name> name doesn't exist	The database doesn't exist	Check the database name at `kustoIngestionProperties`/Create the database
Entity 'table name that doesn't exist' of kind 'Table' wasn't found.	The table doesn't exist and there's no CSV mapping.	Add CSV mapping / create the required table
Blob <blob path> excluded for reason: JSON pattern must be ingested with jsonMapping parameter	JSON ingestion when no JSON mapping is provided.	Provide a JSON mapping
Failed to download blob: 'The remote server returned an error: (404) Not Found.'	The blob doesn't exist.	Verify that the blob exists. If it exists, retry and contact the Kusto team
JSON column mapping isn't valid: Two or more mapping elements point to the same column.	JSON mapping has 2 columns with different paths	Fix JSON mapping
EngineError - [UtilsException] `IngestionDownloader.Download`: One or more files failed to download (search KustoLogs for ActivityID:<GUID1>, RootActivityId:<GUID2>)	One or more files failed to download.	Retry
Failed to parse: Stream with ID '<stream name>' has a malformed CSV format, failing per ValidationOptions policy	Malformed CSV file (such as, not having the same number of columns on every line). Fails only when validation policy is set to `ValidationOptions.ValidateCsvInputConstantColumns`.	Check your CSV files. This message applies only to CSV/TSV files
`IngestClientAggregateException` with error message 'Missing mandatory parameters for valid Shared Access Signature'	The SAS being used is of the service, and not of the storage account	Use the SAS of the storage account

Ingestion error codes

To help handle ingestion failures programmatically, failure information is enriched with a numeric error code (IngestionErrorCode enumeration).

For a full list of ingestion error codes, see Ingestion Error codes.

Detailed exceptions reference

CloudQueuesNotFoundException

Raised when no queues were returned from the Data Management cluster

Base Class: Exception

Field Name	Type	Meaning
Error	`string`	The error that occurred while attempting to retrieve queues from the DM

Relevant only when using the Kusto Queued Ingest Client. During the ingestion process, several attempts are made to retrieve the Azure Queues linked to the DM. When these attempts fail, the exception containing the reason for failure, is raised in the 'Error' field. Possibly an inner exception in the 'InnerException' field is also raised.

CloudBlobContainersNotFoundException

Raised when no blob containers were returned from the Data Management cluster

Base Class: Exception

Field Name	Type	Meaning
KustoEndpoint	`string`	The endpoint of the relevant DM

Relevant only when using the Kusto Queued Ingest Client.
When ingesting sources that aren't already in an Azure container, such as files, DataReader, or Stream, then the data uploads to a temporary blob for ingestion. The exception is raised when there are no containers found to upload the data to.

DuplicateIngestionPropertyException

Raised when an ingestion property is configured more than once

Base Class: Exception

Field Name	Type	Meaning
PropertyName	`string`	The name of the duplicate property

PostMessageToQueueFailedException

Raised when posting a message to the queue fails

Base Class: Exception

Field Name	Type	Meaning
QueueUri	`string`	The URI of the queue
Error	`string`	The error message that was generated while attempting to post to the queue

Relevant only when using the Kusto Queued Ingest Client.
The queued ingest client ingests data by uploading a message to the relevant Azure queue. If there's a post failure, the exception is raised. It will contain the queue URI, the reason for the failure in the 'Error' field, and possibly an inner exception in the 'InnerException' field.