[SERVER-17215] mapReduce with 'reduce' output action fails with an massert on output collection with no _id index Created: 06/Feb/15 Updated: 06/Dec/22 Resolved: 02/Aug/19 |
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| Status: | Closed |
| Project: | Core Server |
| Component/s: | MapReduce |
| Affects Version/s: | 2.4.12, 2.6.7, 3.0.0-rc8 |
| Fix Version/s: | None |
| Type: | Bug | Priority: | Minor - P4 |
| Reporter: | Kamran K. | Assignee: | Backlog - Query Team (Inactive) |
| Resolution: | Done | Votes: | 0 |
| Labels: | 28qa, neweng, query-44-grooming | ||
| Remaining Estimate: | Not Specified | ||
| Time Spent: | Not Specified | ||
| Original Estimate: | Not Specified | ||
| Assigned Teams: |
Query
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| Operating System: | ALL | ||||||||||||||||||||||
| Steps To Reproduce: |
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| Participants: |
| Description |
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A mapReduce command that specifies a 'reduce' output action against a collection without an _id index will fail with an massert. The root cause is a Helpers::findOne call that requires the use of an index: https://github.com/mongodb/mongo/blob/r3.0.0-rc8/src/mongo/db/commands/mr.cpp#L644-L648 Error message:
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| Comments |
| Comment by David Storch [ 02/Aug/19 ] |
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I can no longer reproduce this massert() with the script provided. Also, note that the autoIndexID option on collection creation is no longer permitted on collections outside of the local database. For these reasons, I don't believe the Server Query Team intends to pursue this issue further. Closing as Gone Away. |