[SERVER-63210] Verify spilling logic in HashAgg works for $lookup HJ plans Created: 02/Feb/22  Updated: 16/Feb/22  Resolved: 16/Feb/22

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

Type: Task Priority: Major - P3
Reporter: Eric Cox (Inactive) Assignee: Anna Wawrzyniak
Resolution: Won't Fix Votes: 0
Labels: sbe
Remaining Estimate: Not Specified
Time Spent: Not Specified
Original Estimate: Not Specified

Participants:

 Description   

In PM-2267 spilling to disk in HashAgg stage was implemented to support $group queries that hit the memory limit and would spill to a WT temp store when allowDiskUse=true.

Given that we will use the HashAgg stage to build a hash table for the foreign side and accumulate the set of documents that satisfy the eq predicate between the local/foreign side keys the current spilling implementation might just work for our use-case.

The owner of this ticket should exercise the spilling implementation in HashAgg and see if it is suitable for HJ plans. If changes need to be made to support HJ plans we should do so under this work.  



 Comments   
Comment by Eric Cox (Inactive) [ 16/Feb/22 ]

We decided to implement HJ in a new sbe PlanStage so it will require a new spilling implementation.

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