[SERVER-12795] Penalize ixisect during plan scoring so that it won't get chosen over faster single-index plans Created: 19/Feb/14  Updated: 11/Jul/16  Resolved: 24/Feb/14

Status: Closed
Project: Core Server
Component/s: Querying
Affects Version/s: 2.5.5
Fix Version/s: 2.6.0-rc1

Type: Improvement Priority: Major - P3
Reporter: David Storch Assignee: David Storch
Resolution: Done Votes: 0
Labels: None
Remaining Estimate: Not Specified
Time Spent: Not Specified
Original Estimate: Not Specified

Issue Links:
Related
related to SERVER-12673 index bounds incorrect on compound in... Closed
Participants:

 Description   

We have seen cases where the multi plan runner cannot distinguish between index intersection and single index plans. For instance, if the query has zero results, then all plans could be equally unproductive, and we have no information to distinguish between the various plans (see SERVER-12639). The ixisect plan might be chosen even if it is dramatically slower than the other plans.

We should penalize ixisect plans and require them to make up the delta with a no-fetch bonus.



 Comments   
Comment by Githook User [ 24/Feb/14 ]

Author:

{u'username': u'dstorch', u'name': u'David Storch', u'email': u'david.storch@10gen.com'}

Message: SERVER-12795 penalize ixisect while breaking ties during plan scoring
Branch: master
https://github.com/mongodb/mongo/commit/a9f00ca795116b48abe1396123245502b5aa4590

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