Add ingestion exception log

Author: linda33wj

articles/purview/how-to-monitor-data-map-population.md

@@ -91,6 +91,21 @@ You can click the **run ID** to check more about the scan run details:
 
     - **Duration**: The ingestion duration and the start/end time.
 
+## View the exception log (Preview)
+
+When some assets or relationship fail to ingest into data map during scan, e.g. ingestion status ends up as partially completed, you can see a "**Download log**" button in the [scan run details](#scan-run-details) panel. It provides exception log files which capture the details of the failures.
+
+The following table shows the schema of a log file.
+
+| Column | Description |
+| ------ | ----------- |
+| TimeStamp	| The UTC timestamp when the ingestion operation happens.| 
+| ErrorCode	| Error code of the exception. | 
+| OperationItem	| Identifier for the failed asset/relationship, usually using the fully qualified name. | 
+| Message | More information on which asset/relationship failed to ingest due to what reason. In case of resource set ingestion failure, it may apply to multiple assets matching the same naming pattern, and the message includes the impacted count. |
+
+Currently, the exception log doesn't include failures happened during scan phase (metadata discovery). It will be added later.
+
 ## Monitor links
 
 You can connect other services with Microsoft Purview to establish a "link", which will make the metadata and lineage of that service's assets available to Microsoft Purview. Currently, link is supported for [Azure Data Factory](how-to-link-azure-data-factory.md) and [Azure Synapse Analytics](how-to-lineage-azure-synapse-analytics.md).