[DOCS-1761] Add explanation of "multi" and "reverse" cursors in Explain Output Created: 30/Jul/13 Updated: 11/Jan/17 Resolved: 21/Aug/13 |
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| Status: | Closed |
| Project: | Documentation |
| Component/s: | None |
| Affects Version/s: | None |
| Fix Version/s: | 01112017-cleanup |
| Type: | Task | Priority: | Major - P3 |
| Reporter: | Sam Kleinman (Inactive) | Assignee: | Sam Kleinman (Inactive) |
| Resolution: | Done | Votes: | 0 |
| Labels: | None | ||
| Remaining Estimate: | Not Specified | ||
| Time Spent: | Not Specified | ||
| Original Estimate: | Not Specified | ||
| Participants: | |
| Days since reply: | 10 years, 26 weeks ago |
| Description |
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https://github.com/mongodb/mongo/blob/master/src/mongo/db/btreecursor.cpp#L265 |
| Comments |
| Comment by auto [ 21/Aug/13 ] |
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Author: {u'username': u'tychoish', u'name': u'Sam Kleinman', u'email': u'samk@10gen.com'}Message: |
| Comment by Asya Kamsky [ 30/Jul/13 ] |
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This would be for the line showing index being used: "BtreeCursor xxxx multi" means that multiple entries were looked up during index traversal (individual entries) - simplest way to see this is do db.foo.find({_id:{$in:[1, 100]}}).explain() "BtreeCursor xxxx reverse" means the index was traversed right to left instead of left to right. Easiest way to see that one is to do db.foo.find().sort({_id:-1}).explain() |