[DOCS-12053] Docs for SERVER-36255: Prohibit $out with readConcern level "linearizable" Created: 12/Sep/18  Updated: 13/Nov/23  Resolved: 09/Nov/18

Status: Closed
Project: Documentation
Component/s: manual, Server
Affects Version/s: None
Fix Version/s: 4.1.3, Server_Docs_20231030, Server_Docs_20231106, Server_Docs_20231105, Server_Docs_20231113

Type: Task Priority: Major - P3
Reporter: Kay Kim (Inactive) Assignee: Kay Kim (Inactive)
Resolution: Fixed Votes: 0
Labels: neweng
Remaining Estimate: Not Specified
Time Spent: Not Specified
Original Estimate: Not Specified

Issue Links:
Documented
documents SERVER-36255 Prohibit $out with readConcern level ... Closed
Participants:
Days since reply: 5 years, 13 weeks, 5 days ago
Epic Link: DOCS: 4.2 Server/Tools

 Description   

Description

Description:

This is a backwards-breaking change that removes support for running the aggregate command with a $out stage and readConcern level "linearizable".

Engineering Ticket Description:

In MongoDB 4.0 and earlier, we explicitly ban readConcern level "majority" for aggregation pipelines containing $out.

    auto readConcernLevel = repl::ReadConcernArgs::get(expCtx->opCtx).getLevel();
    uassert(ErrorCodes::InvalidOptions,
            "$out cannot be used with a 'majority' read concern level",
            readConcernLevel != repl::ReadConcernLevel::kMajorityReadConcern);

However, it does allow readConcern level "linearizable". As linearizability is a property of a single document, we will ban a $out aggregation with readConcern level "linearizable", as it isn't clear what semantics will be offered to our users.

This is a backwards-breaking change in 4.2; however, we will allow support for readConcern level "majority" in $out pipelines in SERVER-20445.

Scope of changes

Impact to Other Docs

MVP (Work and Date)

Resources (Scope or Design Docs, Invision, etc.)



 Comments   
Comment by Githook User [ 09/Nov/18 ]

Author:

{'name': 'kay', 'email': 'kay.kim@10gen.com', 'username': 'kay-kim'}

Message: DOCS-12053: 4.2 $out and linearizable read concern
Branch: master
https://github.com/mongodb/docs/commit/39ba33daed9e966f5fece51ded8ca560fe108822

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