[COMPASS-6037] Investigate changes in PM-2664: FTDC metrics for global index builds Created: 18/Aug/22 Updated: 23/Aug/22 Resolved: 23/Aug/22 |
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| Status: | Closed |
| Project: | Compass |
| Component/s: | None |
| Affects Version/s: | None |
| Fix Version/s: | No version |
| Type: | Investigation | Priority: | Major - P3 |
| Reporter: | Backlog - Core Eng Program Management Team | Assignee: | Unassigned |
| Resolution: | Done | Votes: | 0 |
| Labels: | None | ||
| Remaining Estimate: | Not Specified | ||
| Time Spent: | Not Specified | ||
| Original Estimate: | Not Specified | ||
| Issue Links: |
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| Documentation Changes: | Not Needed | ||||
| Description |
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Original Downstream Change Summary the Server documentation will need to be updated as part of these changes. The serverStatus and $currentOp output are being modified as part of PM-2664 and are documented in pages such as https://www.mongodb.com/docs/manual/reference/command/serverStatus/#mongodb-serverstatus-serverstatus.shardingStatistics.resharding Description of Linked TicketEpic Summary SummaryCreate common metrics classes for global indexes builds and resharding. MotivationThe resharding project (PM-234) had added FTDC metrics very late in its development relative to when its data replication components became fully functional. This hindered the team a lot during performance investigations because it left questions open about where the time in the resharding operation was being spent. Extending the set of FTDC metrics available during the global index build and resharding processes will aid in all future investigations. Additionally, the resharding project ended up with error-prone C++ lifetime management because both its FTDC metrics and $currentOp metrics are decorations on the ServiceContext. This design led to multiple bugs where the server crashes around stepdown and step-up. Having the C++ object for $currentOp metrics instead be a member variable on the PrimaryOnlyService::Instance will avoid these issues for the global index builds project and simplify resharding’s design. Cast of Characters
DocumentationProduct Description |