[DOCS-13090] Statement in production notes seems incorrect. Created: 10/Oct/19  Updated: 30/Oct/23  Resolved: 06/Nov/19

Status: Closed
Project: Documentation
Component/s: manual
Affects Version/s: None
Fix Version/s: Server_Docs_20231030

Type: Improvement Priority: Major - P3
Reporter: John Page Assignee: Ravind Kumar (Inactive)
Resolution: Fixed Votes: 0
Labels: docs-investigating
Remaining Estimate: Not Specified
Time Spent: Not Specified
Original Estimate: Not Specified

Issue Links:
Related
is related to DOCS-10562 Add warning about using WiredTiger wi... Closed
Participants:
Days since reply: 4 years, 14 weeks ago
Epic Link: DOCSP-1769
Story Points: 2

 Description   

Description

The statement " WiredTiger storage engine may experience checkpoint hangs on systems with unreliable clocks." seems to have little supporting evidence among our engineers.

https://docs.mongodb.com/v4.0/administration/production-notes/#clock-synchronization

Scope of changes

Impact to Other Docs

MVP (Work and Date)

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



 Comments   
Comment by Ravind Kumar (Inactive) [ 06/Nov/19 ]

Thanks for your patience. Publishing master -> 3.2 now with the updates.

Comment by Githook User [ 06/Nov/19 ]

Author:

{'name': 'Ravind Kumar', 'email': 'ravind.kumar@mongodb.com'}

Message: DOCS-13090: Revise outdated production notes guidance on clock sync
Branch: v3.4
https://github.com/mongodb/docs/commit/c00f9fb9269b53f679733d46cc839a01d8310b9f

Comment by Githook User [ 06/Nov/19 ]

Author:

{'email': 'ravind.kumar@mongodb.com', 'name': 'Ravind Kumar'}

Message: DOCS-13090: Revise outdated production notes guidance on clock sync
Branch: v3.2
https://github.com/mongodb/docs/commit/be53a124240f34b46a13263bb5b0b4384d1cedea

Comment by Githook User [ 06/Nov/19 ]

Author:

{'name': 'Ravind Kumar', 'email': 'ravind.kumar@mongodb.com'}

Message: DOCS-13090: Revise outdated production notes guidance on clock sync
Branch: v3.6
https://github.com/mongodb/docs/commit/d5e5fd4c09fde6e9347d27d15a2ff73012da6449

Comment by Githook User [ 06/Nov/19 ]

Author:

{'name': 'Ravind Kumar', 'email': 'ravind.kumar@mongodb.com'}

Message: DOCS-13090: Revise outdated production notes guidance on clock sync
Branch: v4.0
https://github.com/mongodb/docs/commit/275323cc610772992bc5c87aac18dd5ab3b19970

Comment by Githook User [ 06/Nov/19 ]

Author:

{'name': 'Ravind Kumar', 'email': 'ravind.kumar@mongodb.com'}

Message: DOCS-13090: Revise outdated production notes guidance on clock sync
Branch: master
https://github.com/mongodb/docs/commit/cf621fe42d5b302938abfd9a4ceee52dae1a3171

Comment by Ravind Kumar (Inactive) [ 11/Oct/19 ]

I'm checking w/ the server DS team to confirm whether the NTP clock is required for sharded transactions. cc milkie Based on that answer I'll move forward, as I may not be able to simply nuke the entire section as originally planned.

Comment by Ravind Kumar (Inactive) [ 10/Oct/19 ]

No worries, this seems a straightforward enough fix. I'll try to get to it before the end of the week. Thanks for raising it!

Comment by John Page [ 10/Oct/19 ]

Was unaware of WT-3347, as were others in MongoDB Tech Channel

Comment by Susan LoVerso [ 10/Oct/19 ]

we can safely remove that graf in 3.6+, and perhaps generalize it for 3.2/3.4 to state that the problem is considered resolved in the latest point versions of those releases.

This seems very reasonable to me. The fix is in every latest point release now.

Comment by Ravind Kumar (Inactive) [ 10/Oct/19 ]

So from the original docs ticket, I see

> We should warn users against using MongoDB <3.4.6 on a system with known clock issues.

So maybe this warning only really applies to 3.4.5 and earlier?

As noted in Kevin Arhelger's comment in #mongodb-tech:

> Non-monotonic system clock is known to cause problems; related tickets include WT-3327, WT-SERVER-29102, SERVER-29230
> Plus WT-3461

We'd probably want to confirm with someone from storage (perhaps sue.loverso who worked on WT-3327?) that we can safely remove that graf in 3.6+, and perhaps generalize it for 3.2/3.4 to state that the problem is considered resolved in the latest point versions of those releases.

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