[SERVER-57547] Add SBE builder for $group accumulators Created: 08/Jun/21  Updated: 29/Oct/23  Resolved: 15/Jul/21

Status: Closed
Project: Core Server
Component/s: None
Affects Version/s: None
Fix Version/s: 5.1.0-rc0

Type: Task Priority: Major - P3
Reporter: Ian Boros Assignee: Eric Cox (Inactive)
Resolution: Fixed Votes: 0
Labels: None
Remaining Estimate: Not Specified
Time Spent: Not Specified
Original Estimate: Not Specified

Issue Links:
Depends
depends on SERVER-57899 Make it more convenient to switch on ... Closed
is depended on by SERVER-57549 Implement translation of $accumulator... Backlog
is depended on by SERVER-57550 Implement translation of $addToSet Closed
is depended on by SERVER-57551 Implement translation of $first, $las... Closed
is depended on by SERVER-57552 Implement translation of $stdDevPop a... Closed
is depended on by SERVER-57553 Implement translation of $sum accumul... Closed
is depended on by SERVER-58070 Support accumulator $topN in SBE Closed
Backwards Compatibility: Fully Compatible
Sprint: Query Execution 2021-07-12, Query Execution 2021-07-26
Participants:

 Description   

Unlike agg expressions, which are transformed from Expression* to an SBE PlanStage tree, $group accumulators will need to transformed from from an AccumulationStatement (or related type) into two sets of SBE expressions: one set for "accumulation" and another for "finalization."

For example, $avg will be implemented with two accumulators: one for summing all of the elements and another for counting. The "finalization" expression will divide the sum by the count.

$push on the other hand will be implemented with just an accumulator, which pushes to an array (there is no need for "finalizing").

 



 Comments   
Comment by Vivian Ge (Inactive) [ 06/Oct/21 ]

Updating the fixversion since branching activities occurred yesterday. This ticket will be in rc0 when it’s been triggered. For more active release information, please keep an eye on #server-release. Thank you!

Comment by Githook User [ 15/Jul/21 ]

Author:

{'name': 'Eric Cox', 'email': 'eric.cox@mongodb.com', 'username': 'ericox'}

Message: SERVER-57547 Add SBE builder for group accumulators
Branch: master
https://github.com/mongodb/mongo/commit/7348a8ea1883a250398ea37ba03225ea887ebf13

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