[SERVER-85137] Investigate having queries preemptively copy from the storage engine before a yield Created: 20/Jan/22  Updated: 13/Jan/24  Resolved: 22/Jul/22

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

Type: Task Priority: Major - P3
Reporter: Ian Boros Assignee: Backlog - Storage Execution Team
Resolution: Done Votes: 0
Labels: None
Remaining Estimate: Not Specified
Time Spent: Not Specified
Original Estimate: Not Specified

Issue Links:
Related
Assigned Teams:
Storage Execution
Participants:
Linked BF Score: 135

 Description   

With the "new yielding" behavior, the query system will not reset its storage cursors across getMores or yields, forcing the storage engine to "pin" the data these cursors are positioned at. This resulted in some performance regressions, explained in BF-24012.

Here is a POC of the idea to have the query system preemptively copy data when it is known that either yield or a command will call saveState() momentarily.



 Comments   
Comment by Dianna Hohensee (Inactive) [ 22/Jul/22 ]

This is finished. Investigation was done, and WT-8707 tracked the continued work.

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