[SERVER-79764] Ensure that streaming group over TS keeps running fully classic Created: 04/Aug/23  Updated: 26/Sep/23  Resolved: 26/Sep/23

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

Type: Task Priority: Major - P3
Reporter: Irina Yatsenko (Inactive) Assignee: Backlog - Query Integration
Resolution: Duplicate Votes: 0
Labels: None
Remaining Estimate: Not Specified
Time Spent: Not Specified
Original Estimate: Not Specified

Issue Links:
Duplicate
duplicates SERVER-79061 Block TS queries that use bounded sor... Closed
Assigned Teams:
Query Integration
Participants:

 Description   

See PM-3050 – streaming group is one of the optimizations, added in that project. It replaces $group with $_internalStreamingGroup if the input into the group is sorted on time and the group’s key includes a monotonic derivative of time.

$_internalStreamingGroup isn’t supported in SBE and while the query could benefit from lowering the prefix up to it, we’d rather not risk perf regressions and block it from running in the hybrid mode until $_internalStreamingGroup is implemented in SBE.



 Comments   
Comment by Irina Yatsenko (Inactive) [ 26/Sep/23 ]

The streaming group optimization requires sorting on time similar to the bounded sort optimization so we'll be blocking both by not allowing to lower to SBE pipelines with $sort on the timeField.

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