[SERVER-79805] Explain command does not report executionStats on mongos Created: 07/Aug/23  Updated: 17/Aug/23

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

Type: Improvement Priority: Major - P3
Reporter: Arun Banala Assignee: Backlog - Query Execution
Resolution: Unresolved Votes: 0
Labels: query-product-scope-2, query-product-urgency-3, query-product-value-3
Remaining Estimate: Not Specified
Time Spent: Not Specified
Original Estimate: Not Specified

Assigned Teams:
Query Execution
Participants:

 Description   

I've noticed that for sharded collections, we report executionStats under the shards field for each sub-pipeline that gets executed on the individual shards. But we don't have any information about what is happening on mongos during the $mergeCursors or the stages after the $mergeCursors. For example, a $group or a $sort could spend a significant amount of time after the $mergeCursors and we provide no information about that in the explain. There could also be a network latency between the mongos and mongod communication that would be easy to identify if we report executionStats on mongos.



 Comments   
Comment by Xiaochen Wu [ 17/Aug/23 ]

product triage: We haven't heard any customer asking for this. And since we are introducing a new explain for CQF, we'd defer this effort to future improvements. Sending it to backlog. 

Comment by Ana Meza [ 14/Aug/23 ]

Passing to product to decide on priority

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