[SERVER-208] map reduce api Created: 03/Aug/09 Updated: 12/Jul/16 Resolved: 24/Sep/09 |
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| Status: | Closed |
| Project: | Core Server |
| Component/s: | JavaScript, Usability |
| Affects Version/s: | None |
| Fix Version/s: | 1.1.1 |
| Type: | New Feature | Priority: | Major - P3 |
| Reporter: | Eliot Horowitz (Inactive) | Assignee: | Eliot Horowitz (Inactive) |
| Resolution: | Done | Votes: | 8 |
| Labels: | None | ||
| Remaining Estimate: | Not Specified | ||
| Time Spent: | Not Specified | ||
| Original Estimate: | Not Specified | ||
| Issue Links: |
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| Description |
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This is very similar to group() except group only allows a single key to be extracted per object; map would allow emitting several. And use the map / reduce nomenclature. Needs to work with mongos too. db.coll.mapreduce(queryexpr, mapf, reducef); db.stuff.mapreduce( );} }, ; ); |
| Comments |
| Comment by Eliot Horowitz (Inactive) [ 24/Sep/09 ] |
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simple map/reduce api |
| Comment by Eliot Horowitz (Inactive) [ 07/Aug/09 ] |
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probably store in a temp collection. then you could even query it, etc.... |
| Comment by Ryan Nitz [ 07/Aug/09 ] |
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How are large result datasets going to be handled? Will the results from the various nodes be stored in core or in a tmp document in the database? One of the issues (not sure if they fixed it yet) with GridGain is that the results from all the nodes is sent to a single node and placed in memory. I believe Hadoop handles this by storing all the node results in some sort of tmp file (and then provides a cursor). |