[DOCS-11965] Docs for SERVER-23332: Expose query plan cache key in system.profile entry and query log lines Created: 13/Aug/18  Updated: 13/Nov/23  Resolved: 31/Jan/19

Status: Closed
Project: Documentation
Component/s: manual, Server
Affects Version/s: None
Fix Version/s: 4.1.2, Server_Docs_20231030, Server_Docs_20231106, Server_Docs_20231105, Server_Docs_20231113

Type: Task Priority: Major - P3
Reporter: Kay Kim (Inactive) Assignee: Kay Kim (Inactive)
Resolution: Fixed Votes: 0
Labels: None
Remaining Estimate: Not Specified
Time Spent: Not Specified
Original Estimate: Not Specified

Issue Links:
Documented
documents SERVER-23332 Expose query plan cache key in system... Closed
Duplicate
Related
related to DOCS-11982 Docs for SERVER-36528: Implement $pla... Closed
related to DOCS-12387 Docs for SERVER-33303: Modifying inde... Closed
is related to DOCS-11959 Docs for SERVER-36527: Include queryH... Closed
is related to DOCS-11962 Docs for SERVER-35981: Include hash o... Closed
Participants:
Days since reply: 5 years, 2 weeks ago
Epic Link: DOCS: 4.2 Server/Tools

 Description   

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Original Description

Description:

The "queryHash" is now present in slow query log lines and in system.profile output. We may wish to document this in pages about these debug mechanisms. All queries with the same hash are considered the same "shape", and use the same plan cache entry. This may be useful for diagnosing issues around query performance. Please ask Storch for more details, and to review any proposed documentation changes.

Note that https://jira.mongodb.org/browse/SERVER-35981 added this same 'queryHash' to the plan cache introspection commands output, and https://jira.mongodb.org/browse/SERVER-36527 added it to explain output.

Engineering Ticket Description:

It would be nice if we included a hash of all queries (without their binds) so we can get a sense for unique types of queries being run on a system and to be able to get a better performance profile for "bad" queries. If we could add that hash into the mongod.log we can easily "group" queries for prioritization when telling the customer what to "tweak".

----------------------------

Description

Scope of changes (files that need work and how much)

 

  • 4.2
  • tutorial/manage-the-database-profiler
  • /reference/database-profiler 
  • source/tutorial/evaluate-operation-performance.txt
  • administration/analyzing-mongodb-performance
  • source/includes/fact-log-slow-queries.rst
  • source/includes/options-mongod.yaml
  • source/reference/log-messages.txt

Impact to other docs outside of this product

MVP (work and date?)

Resources (e.g. Scope Docs, Invision)



 Comments   
Comment by Githook User [ 31/Jan/19 ]

Author:

{'email': 'kay.kim@mongodb.com', 'name': 'Kay Kim'}

Message: DOCS-11962,DOCS-12387,DOCS-11959,DOCS-11965: queryHash and planCacheKey
Branch: master
https://github.com/mongodb/docs/commit/0e367a666aac090a7ed617e20309a1b1760911b7

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