[SERVER-1021] if scanAndOrder and full index scan are both options, may want to always try both Created: 14/Apr/10  Updated: 12/Jul/16  Resolved: 07/Jan/14

Status: Closed
Project: Core Server
Component/s: Querying
Affects Version/s: None
Fix Version/s: 2.5.5

Type: Bug Priority: Major - P3
Reporter: Aaron Staple Assignee: Unassigned
Resolution: Done Votes: 0
Labels: None
Remaining Estimate: Not Specified
Time Spent: Not Specified
Original Estimate: Not Specified

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 Description   

think about if there are different cases where we should adjust this policy

see SUPPORT-33 for example



 Comments   
Comment by Aaron Staple [ 14/Apr/10 ]

So depending on the data we can sometimes do scan and order and sometimes can't, even though the queries are basically the same. We decide if a scan is taking too long by comparing nscanned to the last similar query. In the problem case here the last similar query scanned all documents (which was optimal b/c scan and order would use too much memory), so we don't notice a problem.

Comment by Eliot Horowitz (Inactive) [ 14/Apr/10 ]

do you think sometimes its picking the right one and sometimes wrong?
should the logic where if the scan is taking longer than expected the other plans start kck in?

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