Merge pull request #35441 from yorek/rc1-dm-fix

added note about known bug

Author: prmerger-automator[bot]

docs/sql-server/sql-server-2025-known-issues.md

@@ -29,6 +29,7 @@ This article describes known issues for [!INCLUDE [sssql25-md](../includes/sssql
 - [Local ONNX models not supported on Linux operating systems](#local-onnx-models-not-supported-on-linux-operating-systems)
 - [PBKDF2 hashing algorithm can affect login performance](#pbkdf2-hashing-algorithm-can-affect-login-performance)
 - [Access violation exception can occur on readable secondary replicas under certain conditions](#access-violation-exception-can-occur-on-readable-secondary-replicas-under-certain-conditions)
+- [Vector index](#vector-index)
 
 ## Windows Arm64 not supported
 
@@ -131,6 +132,15 @@ ALTER DATABASE SCOPED CONFIGURATION FOR SECONDARY
     SET PARAMETER_SENSITIVE_PLAN_OPTIMIZATION = OFF;
 ```
 
+## Vector index
+
+Currently, when you create a vector index on some datasets, it may return the following errors:
+
+- Error 9829: `STRING_AGG aggregation result exceeded the limit of 8000 bytes. Use LOB types to avoid result truncation.`
+- 42234: `Internal SQL error during DiskANN graph build`
+
+A fix has been identified and will be part of a future release of [!INCLUDE [sssql25-md](../includes/sssql25-md.md)].
+
 ## Related content
 
 - [What's new in SQL Server 2025 Preview](what-s-new-in-sql-server-2025.md)

docs/t-sql/statements/create-vector-index-transact-sql.md

@@ -71,19 +71,19 @@ Table on which the index is created. It must be a base table. Views, temporary t
 
 Column to use to create the vector index. It must be of **vector** type.
 
-### METRIC = { 'cosine' | 'dot' | 'euclidean' }
+### METRIC
 
 A string with the name of the distance metric to use to calculate the distance between the two given vectors. The following distance metrics are supported:
 
 - `cosine` - Cosine distance
 - `euclidean` - Euclidean distance
 - `dot` - (Negative) Dot product
 
-## TYPE = 'DiskANN'
+### TYPE
 
 The type of [ANN algorithm](../../sql-server/ai/vectors.md#approximate-vector-index-and-vector-search-approximate-nearest-neighbors) used to build the index. Only `DiskANN` is currently supported. DiskANN is the default value.
 
-## MAXDOP = *max_degree_of_parallelism*
+### MAXDOP
 
 Overrides the **max degree of parallelism** configuration option for the index operation. For more information, see [Max degree of parallelism](../../database-engine/configure-windows/configure-the-max-degree-of-parallelism-server-configuration-option.md). Use `MAXDOP` to limit the degree of parallelism and the resulting resource consumption for an index build operation.
 
@@ -115,6 +115,15 @@ The current preview has the following limitations:
 - A table with a vector index becomes read only. No data modification is allowed while the vector index is present on the table.
 - Vector indexes aren't replicated to subscribers.
 
+## Known issues
+
+Currently, when you create a vector index on some datasets, it may return the following errors:
+
+- Error 9829: `STRING_AGG aggregation result exceeded the limit of 8000 bytes. Use LOB types to avoid result truncation.`
+- 42234: `Internal SQL error during DiskANN graph build`
+
+For more information, review [Known issues](../../sql-server/sql-server-2025-known-issues.md#vector-index).
+
 ## Permissions
 
 The user must have `ALTER` permission on the table.