Cleanup | Consolidate connection capability metadata by edwardneal · Pull Request #3862 · dotnet/SqlClient

edwardneal · 2025-12-28T23:23:41Z

Description

This PR emerges in part from discussion with @paulmedynski on #3858. We noticed that the json datatype wouldn't appear when running SqlConnection.GetSchema("DataTypes") against an Azure SQL instance. This is because of an underlying design choice in SqlMetaDataFactory: it only uses the SQL Server version number to control whether specific queries are used and specific records are returned. This isn't compatible with Azure SQL (which always returns a version of 12.x.) To fix this, we need SqlMetaDataFactory to be able to make decisions based upon the server capabilities, whether determined by the version, the presence of a FEATUREEXTACK token, or the contents of one of those tokens' values.

In this PR, we introduce a new type, ConnectionCapabilities. This class takes on the responsibility of hosting the various feature flags as an object which SqlConnectionInternal, SqlMetaDataFactory and TdsParser can interrogate to check for feature availability. For good measure, I then plumb this object through to SqlMetaDataFactory. A subsequent PR can work out the best way to implement filtering.

Other points of errata:

Moving the LOGINACK capability/version interrogation into the new type means that we no longer need to keep the original SqlLoginAck instance as a field on SqlConnectionInternal, which means that it never leaves the scope it was created in. I've turned it into a readonly ref struct.
229a04d enables SqlClient to build under the Release configuration. This was necessary to get the benchmarking to work.
Benchmarking confirms that the CPU time, number of Gen0 GCs and memory usage remains identical (or very slightly better - slightly fewer Gen0 collections) between this branch and main.

This is a comparatively large PR, so I've tried to make it practical to move commit-by-commit.

Issues

Builds on a conversation in #3858.
Prerequisite to #3833.

Testing

This is covered by existing tests.

This class parses FEATUREEXTACK and LOGINACK streams, updating an object which specifies the capabilities of a connection.

This also means that we no longer need to hold the original SqlLoginAck record in memory.

This is adjacent cleanup which is best kept separate from the next step.

This includes the now-redundant checking (and associated exception) of the TDS version, and the assignment to _is20XX. Remove the now-redundant _is20XX fields.

We only ever use two of these versions, and they're based on TDS versions rather than SQL Server versions. Convert the Major/Minor/Increment bit-shifting to a constant value for clarity, and associate it with ConnectionCapabilities to eliminate duplication. Also add explanatory comment to describe reason for big-endian vs. little-endian reads.

Move UTF8 feature detection handling to ConnectionCapabilities.

This was always equal to !Capability.DnsCaching.

This enables the if condition from OnFeatureExtAck to continue to apply to capability processing. Also remove now-redundant comments, and clean up one reference to IsSQLDNSCachingSupported.

This is never persisted, and eliminates an allocation

One missing validation path. Also switched conditions to use pattern matching and to better align with original method for easier comparison and better codegen.

github-actions · 2026-02-12T03:01:01Z

This pull request has been marked as stale due to inactivity for more than 30 days.

If you would like to keep this pull request open, please provide an update or respond to any comments. Otherwise, it will be closed automatically in 7 days.

mdaigle · 2026-06-03T17:36:18Z

/azp run

azure-pipelines · 2026-06-03T17:36:44Z

Azure Pipelines successfully started running 2 pipeline(s).

…up/unified-connection-capabilities

mdaigle · 2026-06-24T18:05:28Z

/azp run

azure-pipelines · 2026-06-24T18:07:05Z

Azure Pipelines successfully started running 3 pipeline(s).

paulmedynski

Great changes overall and a good step towards encapsulating concerns in this old spaghetti code! A few questions/comments for your consideration.

Name is misleading, and this corrects the semantics of Is2012OrNewer

mdaigle · 2026-07-06T17:30:54Z

/azp run

azure-pipelines · 2026-07-06T17:31:32Z

Azure Pipelines successfully started running 3 pipeline(s).

Co-authored-by: Malcolm Daigle <mdaigle@microsoft.com>

Remove entries with no customer-visible effect, and reframe entries that led with implementation detail rather than customer impact. Removed: - #3862 ConnectionCapabilities consolidation - internal refactor; the GetSchema("DataTypes") fix it enables is deferred to a later PR. - #3700/#3741 SSRP scaffolding - adds no parsing code and no behavior change. - #4517 CodeQL findings - PKCS#1 half is suppression comments for declared false positives; the SHA-1 removal is a no-op in practice. - #4421 Extensions.Azure APIScan remediation - no public API change and managed-identity behavior preserved exactly; the removed assignment was already a no-op. Extensions.Azure now has no Changed section. Promoted: - #4504 counter fixes moved from a pool V2 sub-bullet into Fixed. These affect the default pool that customers use without opting in, and the previous text understated them as two fixes limited to Count. Reframed: - Cross-platform build collapsed to the one customer-visible outcome (trimming on Linux/macOS); package contents were always unchanged. - #4528 now leads with the allocation regression rather than call-site count. - AKV cache fixes now lead with symptoms (unbounded signature cache growth, duplicate CryptographyClient per key) rather than GetOrCreate/GetOrAdd. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com> Copilot-Session: 8c691319-4c66-40f6-a88e-b453937052f1

* Add release notes for 7.1.0-preview3 Adds release notes for Microsoft.Data.SqlClient 7.1.0-preview3 and its four aligned companion packages, updates the per-version README index tables, and adds the corresponding CHANGELOG entry. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com> Copilot-Session: c7425f3e-f6b8-439b-b74f-e25f8406fbf6 * Capture remaining closed 7.1.0-preview3 milestone items in release notes Adds coverage for milestone items that closed after the initial draft: - #4529 leaked-connection reclamation in ChannelDbConnectionPool - #4535 SqlBulkCopy graph column alias mapping bypass - #4521 / #4496 Entra ID tenant parsing for multi-segment STSURL authorities - #4540 async key store provider APIs in the AzureKeyVaultProvider Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com> Copilot-Session: c485150e-f46e-4c55-8d06-e0491a10e7e8 * Add #4439 and #4445 to 7.1.0-preview3 release notes Both are user-facing fixes merged into the preview3 milestone that were not yet captured in the release notes or CHANGELOG: - #4439: DateOnly values in sql_variant TVP columns were sent as datetime instead of date, overflowing for values outside the datetime range. - #4445: ServerCertificate pin validation was skipped when the platform reported no TLS policy errors, and an unloadable certificate file fell back to host-name validation instead of failing closed. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com> Copilot-Session: 8c691319-4c66-40f6-a88e-b453937052f1 * Add #4474 to 7.1.0-preview3 cross-platform build notes PR #4474 (Remove OS-Specific Builds) removed OS-specific build targets and output paths, and rewrote the MDS nuspec to source a single OS-agnostic assembly for both the win and unix runtime folders. Verified the nuspec change is src-path-only: all 52 file entries have identical target= values before and after, so the produced package layout is unchanged. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com> Copilot-Session: 8c691319-4c66-40f6-a88e-b453937052f1 * Clarify #4536 allocation fix applies to the default async read path Addresses review feedback on PR #4565: the PacketData node-reuse fix is not gated behind UseCompatibilityAsyncBehaviour or any other AppContext switch, and the perf validation was measured on the default path. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com> Copilot-Session: 8c691319-4c66-40f6-a88e-b453937052f1 * Scope preview3 release notes to customer-facing changes Remove entries with no customer-visible effect, and reframe entries that led with implementation detail rather than customer impact. Removed: - #3862 ConnectionCapabilities consolidation - internal refactor; the GetSchema("DataTypes") fix it enables is deferred to a later PR. - #3700/#3741 SSRP scaffolding - adds no parsing code and no behavior change. - #4517 CodeQL findings - PKCS#1 half is suppression comments for declared false positives; the SHA-1 removal is a no-op in practice. - #4421 Extensions.Azure APIScan remediation - no public API change and managed-identity behavior preserved exactly; the removed assignment was already a no-op. Extensions.Azure now has no Changed section. Promoted: - #4504 counter fixes moved from a pool V2 sub-bullet into Fixed. These affect the default pool that customers use without opting in, and the previous text understated them as two fixes limited to Count. Reframed: - Cross-platform build collapsed to the one customer-visible outcome (trimming on Linux/macOS); package contents were always unchanged. - #4528 now leads with the allocation regression rather than call-site count. - AKV cache fixes now lead with symptoms (unbounded signature cache growth, duplicate CryptographyClient per key) rather than GetOrCreate/GetOrAdd. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com> Copilot-Session: 8c691319-4c66-40f6-a88e-b453937052f1 --------- Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com> Copilot-Session: c7425f3e-f6b8-439b-b74f-e25f8406fbf6 Copilot-Session: c485150e-f46e-4c55-8d06-e0491a10e7e8 Copilot-Session: 8c691319-4c66-40f6-a88e-b453937052f1

edwardneal added 23 commits December 27, 2025 15:04

Add ConnectionCapabilities class

a6646c0

This class parses FEATUREEXTACK and LOGINACK streams, updating an object which specifies the capabilities of a connection.

Hook LOGINACK handling

e37f3a2

This also means that we no longer need to hold the original SqlLoginAck record in memory.

Update reference to _is20XX to reference Capabilities property

de5c285

Errata: use BinaryPrimitives

65e701f

This is adjacent cleanup which is best kept separate from the next step.

Move handling of SqlLoginAck to ConnectionCapabilities

943c7db

This includes the now-redundant checking (and associated exception) of the TDS version, and the assignment to _is20XX. Remove the now-redundant _is20XX fields.

Hook FEATUREEXT handling

d68b90c

Move UTF8 feature detection handling to ConnectionCapabilities.

Move JSON feature detection handling

936218e

Move float32 vector feature detection handling

53f8947

Move Azure SQL feature detection handling

8ee0fb4

Add additional detection logic for Global Transactions

7713018

Move Global Transactions feature detection handling

0e1fcc5

Move data classification feature detection handling

ade2336

Move initial SQL DNS caching feature detection handling

ab9ebff

Remove unnecessary _cleanSQLDNSCaching member

abd69b7

This was always equal to !Capability.DnsCaching.

Move column encryption feature detection handling

50ccf47

Move logic to throw on unknown FEATUREEXT tokens into TdsParser

24caa2a

Refactor parsing condition into ShouldProcessFeatureExtAck

984ac2e

This enables the if condition from OnFeatureExtAck to continue to apply to capability processing. Also remove now-redundant comments, and clean up one reference to IsSQLDNSCachingSupported.

Maintain original server version behaviour

9380711

Performance: convert SqlLoginAck to a readonly ref struct

95ac4f5

This is never persisted, and eliminates an allocation

Enable Release mode build

229a04d

Plumb new ConnectionCapabilities to SqlMetaDataFactory

25b01d4

Cross-check FEATUREEXT validation to original OnFeatureExtAck

6560f5f

One missing validation path. Also switched conditions to use pattern matching and to better align with original method for easier comparison and better codegen.

edwardneal requested a review from a team as a code owner December 28, 2025 23:23

github-project-automation Bot added this to SqlClient Board Dec 28, 2025

github-project-automation Bot moved this to To triage in SqlClient Board Dec 28, 2025

cheenamalhotra moved this from To triage to In review in SqlClient Board Jan 5, 2026

cheenamalhotra added the Code Health 💊 Issues/PRs that are targeted to source code quality improvements. label Jan 13, 2026

github-actions Bot added the Stale The Issue or PR has become stale and will be automatically closed shortly if no activity occurs. label Feb 12, 2026

edwardneal mentioned this pull request Jun 15, 2026

Discard Microsoft.Data.SqlCLient.SqlMetaData.xml in favor of storing metadata internally #4362

Open

Merge branch 'main' of https://github.com/dotnet/SqlClient into clean…

49df425

…up/unified-connection-capabilities

mdaigle requested a review from paulmedynski June 24, 2026 18:05

paulmedynski requested changes Jun 26, 2026

View reviewed changes

github-project-automation Bot moved this from In progress to Waiting for customer in SqlClient Board Jun 26, 2026

paulmedynski moved this from Waiting for customer to In review in SqlClient Board Jun 30, 2026

paulmedynski modified the milestones: 7.1.0-preview2, 7.1.0-preview3 Jun 30, 2026

edwardneal added 3 commits July 2, 2026 20:22

Merge main

5aa2223

Code review: Remove Is2022OrNewer

a27ae84

Name is misleading, and this corrects the semantics of Is2012OrNewer

Use feature flags rather than TDS versions

eabf579

edwardneal dismissed mdaigle’s stale review via eabf579 July 2, 2026 20:01

edwardneal requested a review from paulmedynski July 2, 2026 20:29

paulmedynski approved these changes Jul 13, 2026

View reviewed changes

paulmedynski enabled auto-merge (squash) July 13, 2026 18:21

paulmedynski requested a review from mdaigle July 13, 2026 18:21

mdaigle approved these changes Jul 13, 2026

View reviewed changes

paulmedynski merged commit ca469d5 into dotnet:main Jul 13, 2026
354 checks passed

github-project-automation Bot moved this from In review to Done in SqlClient Board Jul 13, 2026

edwardneal deleted the cleanup/unified-connection-capabilities branch July 13, 2026 22:27

cheenamalhotra pushed a commit that referenced this pull request Jul 14, 2026

Cleanup | Consolidate connection capability metadata (#3862)

cf1f277

Co-authored-by: Malcolm Daigle <mdaigle@microsoft.com>

priyankatiwari08 mentioned this pull request Aug 26, 2026

[v7.1.0-preview3] Release Notes #4565

Merged

5 tasks

Navigation Menu

Uh oh!

Cleanup | Consolidate connection capability metadata - #3862

Cleanup | Consolidate connection capability metadata#3862
paulmedynski merged 39 commits into
dotnet:mainfrom
edwardneal:cleanup/unified-connection-capabilities

edwardneal commented Dec 28, 2025 •

edited

Loading

Uh oh!

github-actions Bot commented Feb 12, 2026

Uh oh!

mdaigle commented Jun 3, 2026

Uh oh!

azure-pipelines Bot commented Jun 3, 2026

Uh oh!

mdaigle commented Jun 24, 2026

Uh oh!

azure-pipelines Bot commented Jun 24, 2026

Uh oh!

paulmedynski left a comment

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

mdaigle commented Jul 6, 2026

Uh oh!

azure-pipelines Bot commented Jul 6, 2026

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

6 participants

Uh oh!

Conversation

edwardneal commented Dec 28, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Description

Issues

Testing

Uh oh!

github-actions Bot commented Feb 12, 2026

Uh oh!

mdaigle commented Jun 3, 2026

Uh oh!

azure-pipelines Bot commented Jun 3, 2026

Uh oh!

mdaigle commented Jun 24, 2026

Uh oh!

azure-pipelines Bot commented Jun 24, 2026

Uh oh!

paulmedynski left a comment

Choose a reason for hiding this comment

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

mdaigle commented Jul 6, 2026

Uh oh!

azure-pipelines Bot commented Jul 6, 2026

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

6 participants

edwardneal commented Dec 28, 2025 •

edited

Loading