[SERVER-18081] Tailing the oplog requires paging in the recently added entries under WiredTiger Created: 16/Apr/15 Updated: 06/Dec/22 Resolved: 21/Dec/16 |
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| Status: | Closed |
| Project: | Core Server |
| Component/s: | WiredTiger |
| Affects Version/s: | 3.0.1 |
| Fix Version/s: | None |
| Type: | Bug | Priority: | Major - P3 |
| Reporter: | Bruce Lucas (Inactive) | Assignee: | Backlog - Storage Execution Team |
| Resolution: | Duplicate | Votes: | 0 |
| Labels: | WTcc | ||
| Remaining Estimate: | Not Specified | ||
| Time Spent: | Not Specified | ||
| Original Estimate: | Not Specified | ||
| Issue Links: |
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| Assigned Teams: |
Storage Execution
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| Backwards Compatibility: | Fully Compatible | ||||||||||||||||||||||||||||
| Operating System: | ALL | ||||||||||||||||||||||||||||
| Participants: | |||||||||||||||||||||||||||||
| Description |
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While debugging a large performance drop related to the oplog filling (see Independent of the memory allocator issues on that ticket, it seems that having to page in the recently added oplog entries is not optimal for performance. Is there any way to avoid this? |
| Comments |
| Comment by Daniel Pasette (Inactive) [ 08/Jun/15 ] |
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The actual impact needs to be quantified, but this may be important for primary performance. Most likely to happen when tailing the oplog falls slightly behind, ie, > 10M behind when splits/evictions kick in. Need to pay attention to cache misses on the oplog collection. Keep in mind that truncation at the beginning of the oplog may also cause cache misses. |