[SERVER-27666] listDatabases performance issue w/ replicasets & wiredTiger Created: 12/Jan/17 Updated: 18/Jan/17 Resolved: 18/Jan/17 |
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| Status: | Closed |
| Project: | Core Server |
| Component/s: | Replication, WiredTiger |
| Affects Version/s: | None |
| Fix Version/s: | None |
| Type: | Bug | Priority: | Major - P3 |
| Reporter: | Chad Kreimendahl | Assignee: | Mark Agarunov |
| Resolution: | Duplicate | Votes: | 0 |
| Labels: | None | ||
| Remaining Estimate: | Not Specified | ||
| Time Spent: | Not Specified | ||
| Original Estimate: | Not Specified | ||
| Issue Links: |
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| Operating System: | ALL | ||||||||
| Steps To Reproduce: |
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| Participants: | |||||||||
| Description |
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Each of the non-primary replica members appears to be asking the primary every minute for a "listDatabases". Since each requests takes about 2 seconds, every minute or so, we'll see our members lag on sync, because of this. While some performance issues were fixed in I would suggest creating a listDatabases (like) method that did not get file and index sizes. This would be used for whatever purposes the replicasets require, without creating the massive requests to the filesystem and delays in synchronization |
| Comments |
| Comment by Mark Agarunov [ 18/Jan/17 ] |
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Hello sallgeud, Since this ticket appears to have the same root cause as Thanks, |
| Comment by Chad Kreimendahl [ 12/Jan/17 ] |
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Great. Seems like he got a fairly simple fix in about half a year ago and it's been ignored since. Right now, the command triggers our slow log and is responsible for over 95% of our logs, and 80% of all replica delay. We'll need it on 3.2, as we're several months from going 3.4. |
| Comment by Ramon Fernandez Marina [ 12/Jan/17 ] |
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sallgeud, I believe the behavior you describe may have the same root cause as |