[SERVER-38661] Don't allow read commands to change global read timestamp for sharded transactions Created: 14/Dec/18  Updated: 29/Oct/23  Resolved: 21/Dec/18

Status: Closed
Project: Core Server
Component/s: Sharding
Affects Version/s: None
Fix Version/s: 4.1.7

Type: Task Priority: Major - P3
Reporter: Jack Mulrow Assignee: Jack Mulrow
Resolution: Fixed Votes: 0
Labels: ShardedTxn:GlobalSnapshot
Remaining Estimate: Not Specified
Time Spent: Not Specified
Original Estimate: Not Specified

Backwards Compatibility: Fully Compatible
Sprint: Sharding 2018-12-17, Sharding 2018-12-31
Participants:

 Description   

As a holdover from Global Point in Time reads, find, aggregate, and distinct are able to change the global read timestamp of a transaction during execution, to allow picking a time based off the shards that would be targeted. This logic has been disabled until SERVER-36312 is completed, but these commands may still set the time forward, under the assumption that doing so is safe because any operations that would cause data to move would also force a stale shard version error. There's really no benefit from allowing this behavior, and it could possibly lead to obscure bugs, so it should be disabled and re-enabled as part of SERVER-36312.



 Comments   
Comment by Githook User [ 21/Dec/18 ]

Author:

{'username': 'jsmulrow', 'email': 'jack.mulrow@mongodb.com', 'name': 'Jack Mulrow'}

Message: SERVER-38661 Don't allow read commands to change global read timestamp for sharded transactions
Branch: master
https://github.com/mongodb/mongo/commit/3c140cdd63bbf20e585bbbccd21ed3ea64e656b1

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