[SERVER-39870] WTKVEngine::setOldestFromStable must not choose a time earlier than the initialDataTimestamp Created: 27/Feb/19  Updated: 29/Oct/23  Resolved: 11/Apr/19

Status: Closed
Project: Core Server
Component/s: Storage
Affects Version/s: None
Fix Version/s: 4.1.11

Type: Bug Priority: Major - P3
Reporter: Daniel Gottlieb (Inactive) Assignee: Daniel Gottlieb (Inactive)
Resolution: Fixed Votes: 0
Labels: None
Remaining Estimate: Not Specified
Time Spent: Not Specified
Original Estimate: Not Specified

Backwards Compatibility: Fully Compatible
Operating System: ALL
Sprint: Storage NYC 2019-04-08, Storage NYC 2019-04-22
Participants:

 Description   

The initialDataTimestamp is the earliest time the system knows the data to be consistent. setOldestTimestampFromStable will intentionally lag the oldest timestamp a few seconds behind the stable timestamp to provide a window for reads to get in.

At startup, the initialDataTimestamp will be set to the checkpoint timestamp. The system has no history before this time. However, setOldestFromStable will communicate an earlier oldest_timestamp to WiredTiger. This means a transaction with a read_timestamp can come in that WT will allow, but does not have the history to correctly satisfy.



 Comments   
Comment by Githook User [ 11/Apr/19 ]

Author:

{'name': 'Daniel Gottlieb', 'username': 'dgottlieb', 'email': 'daniel.gottlieb@mongodb.com'}

Message: SERVER-39870: Guarantee the oldest timestamp obeys any initial data timestamp constraints.
Branch: master
https://github.com/mongodb/mongo/commit/95bb948f7e5e573ca1473ba43dd6fd8e53cb5f50

Comment by Suganthi Mani [ 28/Mar/19 ]

As a part of SERVER-39782, to overcome the lag between stable and oldest timestamp during startup recovery, I added a workaround. You can remove it, once this lag issue is fixed.

Comment by Githook User [ 28/Mar/19 ]

Author:

{'name': 'Daniel Gottlieb', 'username': 'dgottlieb', 'email': 'daniel.gottlieb@mongodb.com'}

Message: Revert "SERVER-39870: Guarantee the oldest timestamp obeys any initial data timestamp constraints."

This reverts commit ef38b62f0de257cfa0c5a2940c67949b7402079b.
Branch: master
https://github.com/mongodb/mongo/commit/00afe420f0eccb4204c5a235049385a1189e9c78

Comment by Githook User [ 28/Mar/19 ]

Author:

{'email': 'daniel.gottlieb@mongodb.com', 'name': 'Daniel Gottlieb', 'username': 'dgottlieb'}

Message: SERVER-39870: Guarantee the oldest timestamp obeys any initial data timestamp constraints.
Branch: master
https://github.com/mongodb/mongo/commit/ef38b62f0de257cfa0c5a2940c67949b7402079b

Generated at Thu Feb 08 04:53:22 UTC 2024 using Jira 9.7.1#970001-sha1:2222b88b221c4928ef0de3161136cc90c8356a66.