[Internal]Nregion: Adds support for including nregioncommit synchronous for less than Strong Consistency

[ananth7592]

Description

Feature: N-region synchronous commit support for < Strong consistency in SDK)

This PR brings in N region syncrhonous commit for accounts that have this feature enabled. The feature primarly brings in Barrier requests for Writes for less than Strong consistencies

The change contains two parts (one part is in this PR and other is done in Msdata/released as Direct package version 3.41.0 which is consumed in this PR)

Part 2 THIS PR : V3 Repo changes which include changes in AccountProperties to read the support for Nregion Commit .

-Adds support for including nregioncommit account feature while creating StoreClient within DocumentClient

Part 1 CHanges to ConsistencyWriter for adding Barrier requests and StoreResult to support the new NRegionCommittedGLSN which is critical to performing the barriers.

This is done in the Msdata ShareFiles and a new Direct package version 3.41.0 is released with this change

• Refactors ConsistencyWriter to support synchronous barrier commits in NRegion accounts (< Strong) when EnableNRegionSynchronousCommit is enabled.

• Ensures response is only returned once GlobalNRegionCommittedGLSN has caught up with the write LSN, preserving linearizability

Change PR in msdata: https://msdata.visualstudio.com/CosmosDB/_git/CosmosDB/pullrequest/1800184

Direct package changes

Direct version upgrade to 3.41.0 brings in the following changes

• Part 1 from above: Adds write barrier logic to ConsistencyWriter using StoreResult's N-region committed LSN to enforce N region synchronous commit semantics for less-than-strong consistency writes.
• Introduced SDK support for new regions of SingaporeCentral and SingaporeNorth
• Resolves failover handling in strong consistency writes by ensuring stale barrier context is cleared when retrying across regions.
• Introduced new Length Aware Range Comparators in EPK Range class.

Testing

Emulator test for NregionCommit Write Barrier

Used Http interceptor to "mock" nregioncommit feature enabled in AccountProperties.
Used Transport interceptor to mock GLobalNRegionCommitLSN for testing scenario.

Type of change

Please delete options that are not relevant.

• [] Bug fix (non-breaking change which fixes an issue)
• [] New feature (non-breaking change which adds functionality)
• [] Breaking change (fix or feature that would cause existing functionality to not work as expected)
• [] This change requires a documentation update

Closing issues

To automatically close an issue: closes #IssueNumber

[kundadebdatta]

Since we are bumping up the Direct version, it would be good to highlight the list of features (basically introduced through the cherry-picked commits) brought in through that direct release.

[Copilot]

Pull Request Overview

This PR adds support for N-region synchronous commit functionality for accounts with consistency levels less than Strong. The feature enables barrier requests for writes to ensure linearizability guarantees are maintained when GlobalNRegionCommittedGLSN hasn't caught up with the write LSN.

Key changes:

• Adds EnableNRegionSynchronousCommit property to AccountProperties and AccountConfigurationProperties
• Updates DocumentClient to pass N-region commit configuration to StoreClient during initialization
• Upgrades Direct package version from 3.40.3 to 3.41.0 to support new backend functionality

Reviewed Changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
AccountProperties.cs	Adds EnableNRegionSynchronousCommit property for account-level feature configuration
DocumentClient.cs	Updates CreateStoreModel to extract and pass N-region commit settings to StoreClient
Directory.Build.props	Upgrades DirectVersion to 3.41.0 for backend N-region commit support
StoreReaderTest.cs	Adds comprehensive test for N-region synchronous commit barrier functionality
DocumentClientUnitTests.cs	Adds unit test to verify N-region commit configuration is passed to StoreClient
CosmosJsonSerializerUnitTests.cs	Updates serialization test to include new EnableNRegionSynchronousCommit property
TraceWriter.TraceJsonWriter.cs	Adds GlobalNRegionCommittedGLSN to trace output for debugging
ThinClientTransportSerializer.cs	Duplicates accountName parameter in SerializeProxyRequestAsync call

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[kundadebdatta]

LGTM

[ananth7592]

[celebrate] Ananth Mudumba reacted to your message:

…

________________________________ From: Debdatta Kunda ***@***.***> Sent: Tuesday, September 30, 2025 4:36:00 PM To: Azure/azure-cosmos-dotnet-v3 ***@***.***> Cc: Ananth Mudumba ***@***.***>; Assign ***@***.***> Subject: Re: [Azure/azure-cosmos-dotnet-v3] [Internal]Nregion: Adds support for including nregioncommit synchronous for less than Strong Consistency (PR #5401) @kundadebdatta approved this pull request. LGTM — Reply to this email directly, view it on GitHub<#5401 (review)>, or unsubscribe<https://github.com/notifications/unsubscribe-auth/BMDK6G3XAWWLILEUZFV5HE33VKWPBAVCNFSM6AAAAACGJMOSNOVHI2DSMVQWIX3LMV43YUDVNRWFEZLROVSXG5CSMV3GSZLXHMZTEOBVHA2TKNBZGY>. You are receiving this because you were assigned.Message ID: ***@***.***>

[FabianMeiswinkel]

LGTM - Thanks!