[SERVER-16593] mongod memory usage much larger than cache_size for wiredtiger b-tree Created: 18/Dec/14 Updated: 24/Jan/15 Resolved: 31/Dec/14 |
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| Status: | Closed |
| Project: | Core Server |
| Component/s: | Storage |
| Affects Version/s: | None |
| Fix Version/s: | None |
| Type: | Bug | Priority: | Major - P3 |
| Reporter: | Mark Callaghan | Assignee: | Michael Cahill (Inactive) |
| Resolution: | Duplicate | Votes: | 0 |
| Labels: | None | ||
| Remaining Estimate: | Not Specified | ||
| Time Spent: | Not Specified | ||
| Original Estimate: | Not Specified | ||
| Issue Links: |
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| Backwards Compatibility: | Fully Compatible | ||||||||||||||||
| Operating System: | ALL | ||||||||||||||||
| Steps To Reproduce: | Start WT b-tree via:
With WT LSM this does not reproduce:
mongo.conf is:
The test client is iibench with 10 concurrent load threads as explained in https://jira.mongodb.org/browse/SERVER-16575 |
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| Participants: | |||||||||||||||||
| Description |
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Memory usage by mongod is much larger than the cache_size setting for the WT b-tree. This is also a problem for the WT LSM. When using cache_size=8G and then running iibench I see that mongod vsz and rss are larger than 60G for the WT b-tree: And larger than 30G for the WT LSM: From /proc/$pid/smaps for the WT b-tree there is one huge allocation for the heap: And for the WT LSM the heap allocation isn't as huge (less than 8G): 02c10000-1c46fe000 rw-p 00000000 00:00 0 [heap] |
| Comments |
| Comment by Mark Callaghan [ 29/Dec/14 ] |
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yes |
| Comment by Michael Cahill (Inactive) [ 29/Dec/14 ] |
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mdcallag, I'd like to close this one as a duplicate of |
| Comment by Michael Cahill (Inactive) [ 19/Dec/14 ] |
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Hi mdcallag, This looks like a duplicate of Michael. |