[Delisted] Stable Release v6.1.0
Release Notes
Warning
This release version is delisted from NuGet.org and is no longer supported.
It contains critical bugs that make it unsuitable for use.
Stable Release 6.1.0 - 2025-07-25
This update brings the following changes since the 6.0.2 stable release:
Added
Added dedicated SQL Server vector datatype support
What Changed:
- Optimized vector communications between MDS and SQL Server 2025, employing a custom binary format over the TDS protocol. (#3433, #3443)
- Reduced processing load compared to existing JSON-based vector support.
- Initial support for 32-bit single-precision floating point vectors.
Who Benefits:
- Applications moving large vector data sets will see beneficial improvements to processing times and memory requirements.
- Vector-specific APIs are ready to support future numeric representations with a consistent look-and-feel.
Impact:
- Reduced transmission and processing times for vector operations versus JSON using SQL Server 2025 preview:
- Reads: 50x improvement
- Writes: 3.3x improvement
- Bulk Copy: 19x improvement
- (Observed with vector column of max 1998 size, and 10,000 records for each operation.)
- Improved memory footprint due to the elimination of JSON serialization/deserialization and string representation bloat.
- For backwards compatibility with earlier SQL Server Vector implementations, applications may continue to use JSON strings to send/receive vector data, although they will not see any of the performance improvements noted above.
Revived .NET Standard 2.0 target support
What Changed:
- Support for targeting .NET Standard 2.0 has returned. (#3381)
- Support had previously been removed in the 6.0 release, with the community voicing concerns.
Who Benefits:
- Libraries that depend on MDS may seamlessly target any of the following frameworks:
- .NET Standard 2.0
- .NET Framework 4.6.2 and above
- .NET 8.0
- .NET 9.0
- Applications should continue to target runtimes.
- The MDS .NET Standard 2.0 target framework support does not include an actual implementation, and cannot be used with a runtime.
- An application's build/publish process should always pick the appropriate MDS .NET/.NET Framework runtime implementation.
- Custom build/publish actions that incorrectly try to deploy the MDS .NET Standard 2.0 reference DLL at runtime are not supported.
Impact:
- Libraries targeting .NET Standard 2.0 will no longer receive warnings like this:
warning NU1701: Package 'Microsoft.Data.SqlClient 6.0.2' was restored using '.NETFramework,Version=v4.6.1, .NETFramework,Version=v4.6.2, .NETFramework,Version=v4.7, .NETFramework,Version=v4.7.1, .NETFramework,Version=v4.7.2, .NETFramework,Version=v4.8, .NETFramework,Version=v4.8.1' instead of the project target framework '.NETStandard,Version=v2.0'. This package may not be fully compatible with your project.
Other Additions
- Added packet multiplexing support to improve large data read performance. (#2714, #3161, #3202)
- Added support for special casing with Fabric endpoints. (#3084)
Fixed
- Fixed distributed transactions to be preserved during pooled connection resets. (#3019)
- Fixed application crash when the
Data Source
parameter begins with a comma. (#3250) - Resolved synonym count discrepancies in debug mode. (#3098)
- Addressed warnings for down-level SSL/TLS versions. (#3126)
- Fixed missing <NeutralLanguage> property. (#3325)
- Fixed injection of UTF-8 BOM during bulk copy. (#3399)
- Fixed
SqlCachedBuffer
async read edge case. (#3329) - Fixed
SqlSequentialTextReader
edge case with single-byte reads. (#3383) - Fixed an incorrect error message when parsing connection string
PoolBlockingPeriod
. (#3411) - Added missing
ToString()
override toSqlJson
. (#3427) - Fixed missing socket error codes on non-Windows platforms. (#3475)
- Fixed primary/secondary server SPN handling during SSPI negotiation. (#3478)
- Fixed AzureKeyVaultProvider package key caching to serialize Azure key fetch operations. (#3477)
- Fixed a rare error related to multi-packet async text reads. (#3474)
- Fixed some spelling errors in the API docs. (#3500)
- Fixed a rare multi-packet string corruption bug. (#3513)
Changed
SqlDecimal type workarounds conversions
What Changed:
- Changed how SqlDecimal type workarounds perform conversions to meet compliance policies. (#3467)
Who Benefits:
- Microsoft products must not use undocumented APIs on other Microsoft products. This change removes calls to undocumented APIs and replaces them with compliant API use.
Impact:
- These changes impose an observed 5% decrease in performance on .NET Framework.
SqlVector API improvements (since 6.1.0-preview2)
What Changed:
- Several changes were made to the SqlVector API published in the 6.1.0-preview2 release (#3472):
- The SqlVector class was changed to a readonly struct.
- The null value constructor was changed to a static
CreateNull()
method. - The
Size
property was removed.
Who Benefits:
- SqlVector instances gain the efficiencies of struct handling.
Impact:
- Early-adopter applications may require updates if they rely on the old APIs and any class-specific behaviour.
Other Changes
- Reduced allocations when opening a connection. (#3364)
- Various performance improvements related to TDS parsing. (#3337, #3377, #3422)
- Improved native AOT support. (#3364, #3369, #3401)
- Progress towards SSPI extensibility. (#2454)
- Progress towards connection pooling improvements. (#3352, #3396)
- Expanded/clarified SqlConnection's AccessToken and AccessTokenCallback documentation. (#3339)
- Fixed some poorly formatted tables in the API docs. (#3391)
- Optimized binary size for AOT. (#3091)
- Refined bulk copy operations to handle unmatched column names more effectively. (#3205)
- Enhanced
SqlBulkCopy
to explicitly identify mismatched column names. (#3183) - Optimized outgoing SSPI blob handling using
IBufferWriter<byte>
. (#2452) - Replaced
byte[]
withstring
for SNI to improve efficiency. (#2790) - Code cleanup to remove SQL 2000 support. (#2839, #3206, #3217)
- Connection pool design refactor for a modular connection pool design. (#3199)
- Added dependency on
System.Text.Json
8.0.5 (.NET 8.0) and 9.0.5 (.NET Standard 2.0, .NET 9.0) to avoid transitive vulnerabilities (CVE-2024-43485). (#3403) - Updated various dependencies #3229, primarily:
- System.Text.Encodings.Web to v8.0.0
- System.Text.Json to v8.0.5
- Azure.Identity to v1.13.2
- Microsoft.Identity.Model.Json.Web.Tokens to v7.7.1
- Microsoft.Identity.Model.Protocols.OpenIdConnect to v7.7.1
- Code merge towards a unified SqlClient project, aligning .NET Framework and .NET Core implementations. (Many PRs - see 6.1.0-preview1 and 6.1.0-preview2 for details.)
- Test improvements include a new unit test project, updates to test dependencies, removal of hardcoded credentials, and improved robustness. (Many PRs - see 6.1.0-preview1 and 6.1.0-preview2 for details.)
Contributors
We thank the following public contributors. Their efforts toward this project are very much appreciated.
New Contributors
- BradBarnich made their first contribution in #3325
- deusanyjunior made their first contribution in #3310
- emmanuel-ferdman made their first contribution in #3041
- JNjenga made their first contribution in #3183
- MaceWindu made their first contribution in #3134
- Midhunnnk made their first contribution in #3250
Target Platform Support
- .NET Framework 4.6.2+ (Windows ARM64, Windows x86, Windows x64)
- .NET 8.0+ (Windows x86, Windows x64, Windows ARM64, Windows ARM, Linux, macOS)
Dependencies
.NET Standard 2.0
- Azure.Identity 1.13.2
- Microsoft.Bcl.Cryptography 9.0.4
- Microsoft.Data.SqlClient.SNI.runtime 6.0.2
- Microsoft.Extensions.Caching.Memory 9.0.4
- Microsoft.IdentityModel.JsonWebTokens 7.7.1
- Microsoft.IdentityModel.Protocols.OpenIdConnect 7.7.1
- Microsoft.SqlServer.Server 1.0.0
- System.Configuration.ConfigurationManager 9.0.4
- System.Security.Cryptography.Pkcs 9.0.4
- System.Text.Json 9.0.5
.NET Framework 4.6.2+
- Azure.Identity 1.13.2
- Microsoft.Bcl.Cryptography 8.0.0
- Microsoft.Data.SqlClient.SNI 6.0.2
- Microsoft.Extensions.Caching.Memory 8.0.1
- Microsoft.IdentityModel.JsonWebTokens 7.7.1
- Microsoft.IdentityModel.Protocols.OpenIdConnect 7.7.1
- System.Buffers 4.5.1
- System.Data.Common 4.3.0
- System.Security.Cryptography.Pkcs 8.0.1
- System.Text.Encodings.Web 8.0.0
- System.Text.Json 8.0.5
.NET 8.0
- Azure.Identity 1.13.2
- Microsoft.Bcl.Cryptography 8.0.0
- Microsoft.Data.SqlClient.SNI.runtime 6.0.2
- Microsoft.Extensions.Caching.Memory 8.0.1
- Microsoft.IdentityModel.JsonWebTokens 7.7.1
- Microsoft.IdentityModel.Protocols.OpenIdConnect 7.7.1
- Microsoft.SqlServer.Server 1.0.0
- System.Configuration.ConfigurationManager 8.0.1
- System.Security.Cryptography.Pkcs 8.0.1
- System.Text.Json 8.0.5
.NET 9.0
- Azure.Identity 1.13.2
- Microsoft.Bcl.Cryptography 9.0.4
- Microsoft.Data.SqlClient.SNI.runtime 6.0.2
- Microsoft.Extensions.Caching.Memory 9.0.4
- Microsoft.IdentityModel.JsonWebTokens 7.7.1
- Microsoft.IdentityModel.Protocols.OpenIdConnect 7.7.1
- Microsoft.SqlServer.Server 1.0.0
- System.Configuration.ConfigurationManager 9.0.4
- System.Security.Cryptography.Pkcs 9.0.4
- System.Text.Json 9.0.5