[SERVER-1628] Excessive CPU usage by available replicaset nodes when one node is down Created: 13/Aug/10  Updated: 12/Jul/16  Resolved: 14/Aug/10

Status: Closed
Project: Core Server
Component/s: Performance, Replication
Affects Version/s: 1.6.0
Fix Version/s: 1.6.1, 1.7.0

Type: Bug Priority: Major - P3
Reporter: AndrewK Assignee: Dwight Merriman
Resolution: Done Votes: 0
Labels: None
Remaining Estimate: Not Specified
Time Spent: Not Specified
Original Estimate: Not Specified
Environment:

Windows 7 64bit


Attachments: PNG File excessivecpu.png    
Operating System: ALL
Participants:

 Description   

In a replicaset of 3 idle nodes, when one node is unavailable, the remaining two nodes' processes spike to about 60%-80% CPU usage. The spikes seem to occur in an alternating fashion once a second.

Bringing the missing node back online results in all nodes' processes returning to a consistent <1% cpu usage.

The attached graph shows the processes spiking on CPU #2 (right most graph) and then returning to normal at the end when the 3rd node is brought back online.



 Comments   
Comment by auto [ 16/Aug/10 ]

Author:

{'login': 'erh', 'name': 'Eliot Horowitz', 'email': 'eliot@10gen.com'}

Message: BackgroundJob::wait bug SERVER-1628

Conflicts:

util/background.cpp
http://github.com/mongodb/mongo/commit/67159d2583670da3b299a29d6e96e1afd119d31e

Comment by Dwight Merriman [ 13/Aug/10 ]

1.6.1?

Comment by auto [ 13/Aug/10 ]

Author:

{'login': 'dwight', 'name': 'dwight', 'email': 'dwight@10gen.com'}

Message: BackgroundJob::wait bug SERVER-1628
http://github.com/mongodb/mongo/commit/1bf648b529e51dea9f686745e66038b674d11a1b

Comment by auto [ 13/Aug/10 ]

Author:

{'login': 'dwight', 'name': 'dwight', 'email': 'dwight@10gen.com'}

Message: make BackgroundJob less goofy in its implementation. towards SERVER-1628
http://github.com/mongodb/mongo/commit/38cf4f81f1fe36a2fb5ab839d6114989130abe0b

Comment by Dwight Merriman [ 13/Aug/10 ]

reproduced.
looking into it

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