[SERVER-79873] Provide a knob to disable or adjust updates with damages for a collection Created: 09/Aug/23 Updated: 27/Oct/23 Resolved: 23/Aug/23 |
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| Status: | Closed |
| Project: | Core Server |
| Component/s: | None |
| Affects Version/s: | None |
| Fix Version/s: | None |
| Type: | Improvement | Priority: | Major - P3 |
| Reporter: | Sulabh Mahajan | Assignee: | Gregory Wlodarek |
| Resolution: | Works as Designed | Votes: | 0 |
| Labels: | None | ||
| Remaining Estimate: | Not Specified | ||
| Time Spent: | Not Specified | ||
| Original Estimate: | Not Specified | ||
| Issue Links: |
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| Assigned Teams: |
Storage Execution NAMER
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| Backport Requested: |
v7.0, v6.0, v5.0, v4.4
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| Sprint: | Execution NAMR Team 2023-09-04 | ||||||||||||||||||||
| Participants: | |||||||||||||||||||||
| Description |
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Updates-with-damages uses WiredTiger's modify operation instead of the usual update operation. Whereas an update is a full new value for a document, the modify is a delta on top of the previous value. Using a modify instead of an update benefits using lesser cache and reduces log amplification. But this comes at the performance cost of reads and writes, as full values need to be computed, which might need coalescing several modify on top of a base update. Currently, there is no way to disable or tune the usage of updates-with-damages, so if a workload generates a lot of modify with a high-performance penalty, we can't mitigate the situation. This ticket can explore providing knob(s) to disable updates-with-damages on a collection or reduce how often modify get generated. |
| Comments |
| Comment by Geert Bosch [ 23/Aug/23 ] |
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We didn't actually observe this being an issue, so we don't want to add the complexity of an extra knob. |