[DOCS-14906] Investigate changes in SERVER-54909: In replSetGetStatus, report last durable and last applied operation wall times for all members Created: 28/Oct/21  Updated: 13/Nov/23  Due: 21/Jan/22  Resolved: 20/Jan/22

Status: Closed
Project: Documentation
Component/s: manual, Server
Affects Version/s: None
Fix Version/s: 5.2.0, 4.4.11, 5.0.5, 5.1.1, Server_Docs_20231030, Server_Docs_20231106, Server_Docs_20231105, Server_Docs_20231113

Type: Task Priority: Major - P3
Reporter: Backlog - Core Eng Program Management Team Assignee: Joseph Dougherty
Resolution: Fixed Votes: 0
Labels: None
Remaining Estimate: Not Specified
Time Spent: Not Specified
Original Estimate: Not Specified

Issue Links:
Backports
backported by DOCS-14943 [SERVER][BACKPORT] [v5.1] In replSetG... Closed
backported by DOCS-14945 [SERVER][BACKPORT] [v4.4] In replSetG... Closed
backports DOCS-14944 [SERVER][BACKPORT] [v5.0] In replSetG... Closed
Documented
documents SERVER-54909 In replSetGetStatus, report last dura... Closed
Related
related to DOCS-14943 [SERVER][BACKPORT] [v5.1] In replSetG... Closed
is related to DOCS-14944 [SERVER][BACKPORT] [v5.0] In replSetG... Closed
is related to DOCS-14945 [SERVER][BACKPORT] [v4.4] In replSetG... Closed
Participants:
Days since reply: 2 years, 3 weeks ago
Epic Link: DOCSP-17171
Story Points: 2

 Description   
Downstream Change Summary

New fields in replSetGetStatus: "lastAppliedWallTime" and "lastDurableWallTime" now included for each member in the config.

Description of Linked Ticket

Beginning in 4.2, MongoDB records the wall clock time at which the primary processes each operation with millisecond granularity and records the value in the oplog. Secondary nodes report these values back to the primary node when the issue replSetUpdatePosition, and the information is duly recorded in the TopologyCoordinator's data structure of member data.

If we went a step further and reported these values in the output of replSetGetStatus, it would be possible to calculate and report the primary's estimate of each secondary's replication lag in milliseconds. Presently, the optime is used to approximate this calculation, but it only has whole-second granularity, and due to monotonicity requirements can be incorrect for a long time after a clock adjustment on the primary node.

So, we should add, to each element of the members field returned in replSetGetStatus's response, that member's most recently reported last durable and last applied operation wall clock timestamps.



 Comments   
Comment by Githook User [ 20/Jan/22 ]

Author:

{'name': 'jmd-mongo', 'email': '73852296+jmd-mongo@users.noreply.github.com', 'username': 'jmd-mongo'}

Message: DOCS-14906 new replSetGetStatus output fields (#199)

  • clarifies lastAppliedWallTime
  • rewording
Comment by Githook User [ 19/Jan/22 ]

Author:

{'name': 'jmd-mongo', 'email': '73852296+jmd-mongo@users.noreply.github.com', 'username': 'jmd-mongo'}

Message: [BACKPORT] new replSetGetStatus output fields v4.4 (#356)

  • DOCS-14906 new replSetGetStatus output fields (#199)
  • clarifies lastAppliedWallTime
  • rewording
  • tech review updates
Comment by Githook User [ 19/Jan/22 ]

Author:

{'name': 'jmd-mongo', 'email': '73852296+jmd-mongo@users.noreply.github.com', 'username': 'jmd-mongo'}

Message: [BACKPORT] new replSetGetStatus output fields v5.0 (#355)

  • DOCS-14906 new replSetGetStatus output fields (#199)
  • clarifies lastAppliedWallTime
  • rewording
  • tech review updates
Comment by Githook User [ 19/Jan/22 ]

Author:

{'name': 'jmd-mongo', 'email': '73852296+jmd-mongo@users.noreply.github.com', 'username': 'jmd-mongo'}

Message: [BACKPORT] new replSetGetStatus output fields (#353)

  • DOCS-14906 new replSetGetStatus output fields (#199)
  • clarifies lastAppliedWallTime
  • rewording
  • tech review updates
Comment by Githook User [ 19/Jan/22 ]

Author:

{'name': 'jmd-mongo', 'email': '73852296+jmd-mongo@users.noreply.github.com', 'username': 'jmd-mongo'}

Message: DOCS-14906 new replSetGetStatus output fields (#199)

  • clarifies lastAppliedWallTime
  • rewording
Comment by PM Bot [ 28/Oct/21 ]

Downstream changes updated for upstream SERVER-54909:
New fields in replSetGetStatus: "lastAppliedWallTime" and "lastDurableWallTime" now included for each member in the config.

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