[SERVER-64219] $last/$first window functions repeat evaluation for every document in a static window Created: 04/Mar/22  Updated: 06/Dec/22

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

Type: Improvement Priority: Major - P3
Reporter: Nicholas Zolnierz Assignee: Backlog - Query Optimization
Resolution: Unresolved Votes: 0
Labels: None
Remaining Estimate: Not Specified
Time Spent: Not Specified
Original Estimate: Not Specified

Assigned Teams:
Query Optimization
Participants:

 Description   

The executors for $last/$first do not cache results, even if the window is static ([unbounded, unbounded]). This means that we will evaluate the same expression against the same document for every document in the window.

Without partitioning it's probably not an interesting case, but I could imagine a query such as "give me the last measurement per device" would be impacted by this.


Generated at Thu Feb 08 05:59:48 UTC 2024 using Jira 9.7.1#970001-sha1:2222b88b221c4928ef0de3161136cc90c8356a66.