[DOCS-13775] Investigate changes in SERVER-47824: Ban transaction snapshot reads on capped collections Created: 20/Jul/20  Updated: 13/Nov/23  Resolved: 11/Feb/21

Status: Closed
Project: Documentation
Component/s: manual, Server
Affects Version/s: None
Fix Version/s: 4.7.0, 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: Naomi Pentrel (Inactive)
Resolution: Done Votes: 0
Labels: None
Remaining Estimate: Not Specified
Time Spent: Not Specified
Original Estimate: Not Specified

Issue Links:
Documented
documents SERVER-47824 Ban transaction snapshot reads on cap... Closed
Participants:
Days since reply: 2 years, 51 weeks, 6 days ago
Epic Link: DOCSP-9747
Story Points: 2

 Description   

Description

Downstream Change Summary

Transaction snapshot reads are now banned on capped collections.

Description of Linked Ticket

Capped collections typically (always?) delete records with an unreplicated/untimestamped write. Those deletions will always become visible in a newer transaction. So if a transaction uses snapshot with an atClusterTime (e.g. coming from mongos), it may not see some deleted documents even if they existed at the point in time requested.

Snapshot transactions without atClusterTime might still work if the snapshot is open before the deletions happen probably because they hold onto the WT txn and the snapshot. But I am not 100% sure. Either way, it seems that we will still have to ban transaction snapshot reads on capped collections unless we choose to timestamp the capped collection deletions.

Scope of changes

Pages to review and update:

Impact to Other Docs

MVP (Work and Date)

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



 Comments   
Comment by Githook User [ 11/Feb/21 ]

Author:

{'name': 'Naomi Pentrel', 'email': '5212232+npentrel@users.noreply.github.com', 'username': 'npentrel'}

Message: DOCS-13775 Ban snapshot reads on capped colls
Branch: v5.0
https://github.com/mongodb/docs/commit/6a11e30f0dadb831bd854b746ca1e7b1f4293ed8

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