[DOCS-3286] Map/reduce documentation is wrong about write lock Created: 27/Apr/14  Updated: 05/May/14  Resolved: 05/May/14

Status: Closed
Project: Documentation
Component/s: manual
Affects Version/s: None
Fix Version/s: v1.3.5

Type: Bug Priority: Major - P3
Reporter: Andre Spiegel Assignee: Sam Kleinman (Inactive)
Resolution: Done Votes: 0
Labels: None
Remaining Estimate: Not Specified
Time Spent: Not Specified
Original Estimate: Not Specified

Issue Links:
Related
related to SERVER-13552 remove unnecessary global lock during... Backlog
Participants:
Days since reply: 9 years, 41 weeks, 2 days ago

 Description   

The page on concurrency in map/reduce (http://docs.mongodb.org/manual/core/map-reduce-concurrency/) should make it clear that the write lock taken during the reduce phase is actually a global lock, rather than just a database-level lock. Also, while in non-atomic mode the lock is released and re-acquired for every single document that is written, the lock is pre-emptive in that case and thus has essentially the same effect as in atomic mode, rendering the server inaccessible for any other operation.

(Compare SERVER-13552 where this issue is tracked.)



 Comments   
Comment by Githook User [ 05/May/14 ]

Author:

{u'username': u'tychoish', u'name': u'Sam Kleinman', u'email': u'samk@10gen.com'}

Message: DOCS-3286: clarification about map reduce lock during reduce phase
Branch: v2.4
https://github.com/mongodb/docs/commit/c33f5027ab7d7230259f111ffaafe6ebbca3676f

Comment by Githook User [ 05/May/14 ]

Author:

{u'username': u'tychoish', u'name': u'Sam Kleinman', u'email': u'samk@10gen.com'}

Message: DOCS-3286: clarification about map reduce lock during reduce phase
Branch: master
https://github.com/mongodb/docs/commit/b05dd7e2517e9817552ed75b23c5a6e5763c6be0

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