[SERVER-27262] Wiredtiger cache usage is higher than normal status, so eviction thread never sleep Created: 02/Dec/16 Updated: 08/Feb/23 Resolved: 06/Jan/17 |
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| Status: | Closed |
| Project: | Core Server |
| Component/s: | WiredTiger |
| Affects Version/s: | 3.2.9 |
| Fix Version/s: | None |
| Type: | Bug | Priority: | Major - P3 |
| Reporter: | 아나 하리 | Assignee: | Kelsey Schubert |
| Resolution: | Done | Votes: | 0 |
| Labels: | None | ||
| Remaining Estimate: | Not Specified | ||
| Time Spent: | Not Specified | ||
| Original Estimate: | Not Specified | ||
| Attachments: |
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| Operating System: | ALL |
| Participants: |
| Description |
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in Two shards mongodb cluster, one primary's wiredtiger cache usage is staying about 90%.
We query a lot of data selecting query(about 27000 docs x 30 times) on both primary member. Looks like cache usage is not dropped stable status (like 80~85%), so eviction thread never stop scanning pages. I don't know why cache usage is never drop to stable status. According to stacktrace, one thread is doing "__tree_walk_internal()", acutally 2 threads and they are consuming 1 cpu core by turns. |
| Comments |
| Comment by Kelsey Schubert [ 06/Jan/17 ] |
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Hi matt.lee, Since we haven't heard back from you regarding this issue since upgrading to MongoDB 3.2.11, I assume you haven't seen this issue again. If that's the case, I'd like to close this ticket. If you see this issue again on a later version of MongoDB, please let us know so we can reopen this ticket and continue to investigate. Kind regards, |
| Comment by 아나 하리 [ 06/Dec/16 ] |
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Hi Bruce. This case (eviction thread can't sleep) has gone yesterday. (We have not done anything). Thanks. |
| Comment by Bruce Lucas (Inactive) [ 05/Dec/16 ] |
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Hi Matt, There were also substantial improvements in cache management after 3.2.9. Would you be able to test whether the most recent 3.2 version, 3.2.11, has better eviction behavior on your workload? It also collects additional internal metrics that may help us understand the behavior on you workload better. Thanks, |
| Comment by 아나 하리 [ 05/Dec/16 ] |
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@Alexander Gorrod Sorry it's typo, Could you change it to 3.2.9? Regards, |
| Comment by Alexander Gorrod [ 05/Dec/16 ] |
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This ticket references MongoDB 3.0.9. We have made a lot of improvements to WiredTiger cache management (eviction) since the 3.0.9 release. We recommend that you upgrade to the 3.4.0 release of MongoDB - please let us know if your issue has not been resolved in a more recent release. |