[SERVER-57308] Further investigate slow deletion of chunks Created: 31/May/21  Updated: 27/Oct/23  Resolved: 01/Jun/21

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

Type: Task Priority: Major - P3
Reporter: Pierlauro Sciarelli Assignee: Pierlauro Sciarelli
Resolution: Works as Designed Votes: 0
Labels: PM-1965-Cleanup
Remaining Estimate: Not Specified
Time Spent: Not Specified
Original Estimate: Not Specified

Issue Links:
Related
related to SERVER-57307 Improve deletion of config.chunks ent... Closed
Sprint: Sharding EMEA 2021-06-14
Participants:

 Description   

SERVER-57221 highlighted performance problems on deletes for collections with more than one secondary index and SERVER-57307 mitigates the problem with the use of a hint for chunk documents deletion.

However, the ~17x performance gain showed in SERVER-57221 does not seem to correspond to the ~5x gain obtained when locally testing SERVER-57307 changes.

Investigate what leads to such a difference. Some options to check would be: interference on the machine, documents size, presence of specific config server hooks/observers, number of secondaries, sharding-specific overhead (since the test was done on a plain RS).



 Comments   
Comment by Pierlauro Sciarelli [ 01/Jun/21 ]

Closing as "Works as designed" because there are no relevant differences in performance between the example in SERVER-57221 and the deletion of entries in config.chunks as part of a drop collection.

Testing on the virtual workstation for hours has shown very consistently a speed up of 5x-6x using the hint in both cases.

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