[DOCS-14454] Investigate changes in SERVER-48380: Expose total data size in bytes processed by $sort and $group in agg execution stats explain Created: 13/May/21 Updated: 13/Nov/23 Due: 27/Aug/21 Resolved: 23/Aug/21 |
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| Status: | Closed |
| Project: | Documentation |
| Component/s: | manual, Server |
| Affects Version/s: | None |
| Fix Version/s: | 4.9.0, Server_Docs_20231030, Server_Docs_20231106, Server_Docs_20231105, Server_Docs_20231113 |
| Type: | Task | Priority: | Major - P3 |
| Reporter: | Backlog - Core Eng Program Management Team | Assignee: | Joseph Dougherty |
| Resolution: | Done | Votes: | 0 |
| Labels: | None | ||
| Remaining Estimate: | Not Specified | ||
| Time Spent: | Not Specified | ||
| Original Estimate: | Not Specified | ||
| Issue Links: |
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| Participants: | |||||||||
| Days since reply: | 2 years, 24 weeks, 5 days ago | ||||||||
| Epic Link: | DOCSP-9747 | ||||||||
| Story Points: | 3 | ||||||||
| Description |
DescriptionDownstream Change Summary When running an explain of an aggregation pipeline containing $sort or $group when the verbosity is executionStats or above, the output will contain some extra fields exposing the amount of data processed. The new fields are, for each stage: $sort:
$group:
Description of Linked Ticket One suggestion from alex.bevilacqua is to expose the amount of data processed by $sort or $group. We have such stats for sorts executed in the PlanStage layer, but not for sorts executed in the DocumentSource layer. The $sort stage would report a totalDataSizeSorted metric, and the $group stage would report totalDataSizeGrouped. Another idea that we could consider implementing at the same time is to report usedDisk:true when either a $sort or a $group spills to disk at runtime. Scope of changesImpact to Other DocsMVP (Work and Date)Resources (Scope or Design Docs, Invision, etc.) |
| Comments |
| Comment by Githook User [ 20/Aug/21 ] | ||||||||||||
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Author: {'name': 'Joseph Dougherty', 'email': 'joseph.dougherty@mongodb.com', 'username': 'jmd-mongo'}Message: | ||||||||||||
| Comment by Joseph Dougherty [ 26/Jul/21 ] | ||||||||||||
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Hello rishab.joshi! Have you had a chance to look at this one? Thank you, | ||||||||||||
| Comment by Joseph Dougherty [ 13/Jul/21 ] | ||||||||||||
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Hello rishab.joshi! I'm in the process of documenting these new attributes, but my test results don't seem correct. Would you mind taking a look? I'm using MongoDB 5.0.0 with Mongosh 1.0.0. I've run the sample query (found in the issue summary here), but found the results to be different than expected. Sample query:
Here are my results for the $group stage:
I'm not sure why I'm seeing totalOutputDataSizeBytes when I'd expected to see totalDataSizeBytesEstimate. Is there something else I need to do in order to trigger the desired behavior, or am I possibly looking in the incorrect place in the explain output? Thanks for your help! |