[DOCS-12387] Docs for SERVER-33303: Modifying indexes impacts application of index filters Created: 23/Jan/19  Updated: 13/Nov/23  Resolved: 31/Jan/19

Status: Closed
Project: Documentation
Component/s: manual, Server
Affects Version/s: None
Fix Version/s: 4.1.5, 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: QFB, storch
Remaining Estimate: Not Specified
Time Spent: Not Specified
Original Estimate: Not Specified

Issue Links:
Documented
documents SERVER-33303 Modifying indexes impacts application... Closed
Duplicate
Related
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
is related to DOCS-11965 Docs for SERVER-23332: Expose query p... Closed
is related to DOCS-11982 Docs for SERVER-36528: Implement $pla... Closed
Participants:
Days since reply: 5 years, 2 weeks ago
Epic Link: DOCS: 4.2 Server/Tools

 Description   

Description

 

Description:

This introduces the "planCacheKey" field to explain/logger/debug output.

To summarize the difference between planCacheKey and queryHash:

queryHash is "stable" across catalog changes. That is, the "query shape" (and thus, the hash of theh query shape) is derived from the query the user wrote down, and does not depend on any state inside the server. It will not change if you add/drop/change indexes.

planCacheKey is "unstable" across catalog changes. It depends both on the query shape and which indexes are available.

This is slightly confusing even for us so if you have questions definitely slack/email me!(ian.boros/ianb)

Engineering Ticket Description:

According to the documentation:

Index filters exist for the duration of the server process and do not persist after shutdown. MongoDB also provides a command to manually remove filters.

 

While a given index filter does persist across index creation and drops, its application towards queries does seem to be influenced by such actions.

Scope of changes

  • source/reference/explain-results
  • profiler
  • log messages
  • 4.2
  • possibly regarding:
    • plan cache filter
    • analyzing mongodb perf
    • core/query-plans
    • core/query-optimization
    • tutorial/evaluate-operation-performance
    • tutorial/manage-indexes

Impact to Other Docs

MVP (Work and Date)

Resources (Scope or Design Docs, Invision, etc.)



 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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