[DOCS-2743] Running explain no longer causes the query planner cache to be dropped Created: 18/Feb/14  Updated: 05/Mar/14  Resolved: 05/Mar/14

Status: Closed
Project: Documentation
Component/s: manual
Affects Version/s: None
Fix Version/s: v1.3.2

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

Issue Links:
Related
related to SERVER-7468 Don't invalidate query plans when exp... Closed
Participants:
Days since reply: 9 years, 50 weeks ago

 Description   

Up until 2.5.5, when a user ran explain on a query, it would have the side effect of dropping the query plan cache for that query "shape."

In 2.5.5+ this behavior no longer holds true and the full set of plans which are considered for the query are pulled from the queryPlanCache itself.

The only direct user-triggered way of dropping the cached plan for a query is by using the QueryPlanCache manipulation methods directly.

I'm not sure if this is mentioned anywhere in our documentation or whether this should be documented specifically, but it is a known behavior pre 2.5.5 and this is a backwards breaking change for users who depended on this behavior.

See: SERVER-7468



 Comments   
Comment by Githook User [ 05/Mar/14 ]

Author:

{u'username': u'kay-kim', u'name': u'kay', u'email': u'kay.kim@10gen.com'}

Message: DOCS-2826 DOCS-2743 DOCS-2650 DOCS-2465 DOCS-2726 backwards compatibility and release notes cleanup
Branch: master
https://github.com/mongodb/docs/commit/94f29def1eda4f0f24d247fa0b3172dabe43d813

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