[DOCS-9448] Consider documenting how statistics for views are tracked in top/histogram Created: 02/Dec/16  Updated: 24/Mar/23  Resolved: 24/Mar/23

Status: Closed
Project: Documentation
Component/s: Server
Affects Version/s: None
Fix Version/s: 3.4.0

Type: Task Priority: Major - P3
Reporter: Emily Hall Assignee: Kay Kim (Inactive)
Resolution: Won't Do Votes: 0
Labels: read-only-views
Remaining Estimate: Not Specified
Time Spent: Not Specified
Original Estimate: Not Specified

Issue Links:
Documented
documents SERVER-24568 Reflect operations on views in their ... Closed
Participants:
Days since reply: 45 weeks, 5 days ago
Epic Link: 3.4: Views

 Description   

We should consider documenting how statistics are tracked for views in stats counters like Top and the histogram. As of 3.4.0, MongoDB double-counts operations performed on views: once on the view, and once on the underlying collection that the view resolves to. As an example, consider

view1 -> view2 -> view3 -> collection

where a -> b indicates that a is a view on b. Then, a query against view1 will have stats counters incremented for both the namespaces view1 and collection.

In terms of counting time, the command's execution time in collection is the time it took to run the fully-transformed view pipeline against collection. The execution time in view1 is the execution time of collection, plus the time spent transforming and processing the original view query.


Original Engineering Ticket Description:

When executing queries on views, they should be counted both on the underlying collection and on the view itself. It is important to see operations on the underlying collection to decide on indexes etc, and it is important to see operations on the view to know where they come from.



 Comments   
Comment by Sarah Olson [ 24/Mar/23 ]

Closing this out on the grounds that:

  • Details of this request are significantly outdated. 
  • Our documentation has evolved substantially since this request was made. 

Based on this, closing as WON'T DO. Please don't hesitate to give me a shout or to reopen if you disagree.

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