[SERVER-83196] SBE multiplanning may chooses the wrong plan Created: 13/Nov/23  Updated: 30/Nov/23

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

Type: Bug Priority: Major - P3
Reporter: Xiaochen Wu Assignee: Backlog - Query Optimization
Resolution: Unresolved Votes: 1
Labels: query-director-triage
Remaining Estimate: Not Specified
Time Spent: Not Specified
Original Estimate: Not Specified

Issue Links:
Duplicate
is duplicated by SERVER-82217 Filter query with sort performs much ... Closed
Related
related to SERVER-62150 SBE Multiplanning can be slow when su... Open
Assigned Teams:
Query Optimization
Operating System: ALL
Participants:

 Description   

For SBE, we implemented a default limit of 10,000 reads for each candidate plan. This bounds the expense of the trial period cost at 10,000n where n is the number of plans – an important backstop given that we may incidentally trial the “wrong” plan(s) first. However, this limit can be much higher for the Classic multi-planner. As a result, the SBE multi-planner will sometimes do less partial execution than the Classic multi-planner, rendering it unable to distinguish amongst plans when no well-indexed plan exists.


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