[SERVER-80494] [CQF] Adjust CE in cost model to account for RemoveOrphansRequirement Created: 29/Aug/23  Updated: 29/Oct/23  Resolved: 29/Aug/23

Status: Closed
Project: Core Server
Component/s: None
Affects Version/s: None
Fix Version/s: 7.2.0-rc0

Type: Task Priority: Major - P3
Reporter: Ben Shteinfeld Assignee: Ben Shteinfeld
Resolution: Fixed Votes: 0
Labels: None
Remaining Estimate: Not Specified
Time Spent: Not Specified
Original Estimate: Not Specified

Issue Links:
Issue split
split from SERVER-79608 [CQF] Satisfy RemoveOrphansRequiremen... Closed
Backwards Compatibility: Fully Compatible
Sprint: QO 2023-09-04
Participants:

 Description   

When we are optimizing a group with RemoveOrphansRequirement = false, the logical CE which doesn't include orphans differs from the "physical CE" because at execution time, the plan fragment will encounter orphaned documents. To account for this discrepancy, this ticket will adjust the CE of such a group by a small "fudge factor" to account for these extra documents.



 Comments   
Comment by Githook User [ 29/Aug/23 ]

Author:

{'name': 'Ben Shteinfeld', 'email': 'ben.shteinfeld@mongodb.com', 'username': 'bshteinfeld'}

Message: SERVER-80494 Adjust CE in cost model based on RemoveOrphansRequirement

Logical CE does not contain orphans but subtrees of a plan which haven't
filtered orphans will encounter them during execution. To account for
this discrepancy, this patch adds a small "fudge factor" to the CE which
the costing module uses to determine the cost of a plan fragment.
Branch: master
https://github.com/mongodb/mongo/commit/99c0b1b3806f45f081b438731074feed15d15a80

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