[SERVER-68442] Make mongos capture read/write latency for a collection Created: 29/Jul/22 Updated: 09/Nov/22 |
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| Status: | Backlog |
| Project: | Core Server |
| Component/s: | None |
| Affects Version/s: | None |
| Fix Version/s: | None |
| Type: | Task | Priority: | Major - P3 |
| Reporter: | Cheahuychou Mao | Assignee: | Garaudy Etienne |
| Resolution: | Unresolved | Votes: | 0 |
| Labels: | None | ||
| Remaining Estimate: | Not Specified | ||
| Time Spent: | Not Specified | ||
| Original Estimate: | Not Specified | ||
| Issue Links: |
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| Description |
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Mongod captures the latency metrics of reads and writes to a collection and exposes them via $collStats. However, mongos doesn't do that. Running $collStats against a mongos returns the latencyStats for each shard in a separate document along with the other stats. Similar to |
| Comments |
| Comment by Garaudy Etienne [ 11/Oct/22 ] |
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From Cailin: "I spent several hours today failing to notice that one mongos (out of 36) in a sharded cluster was unhealthy and causing substantial application slowness. Given the metrics available, the only metric that did indicate "unhealthy" was virtual memory. But... I didn't think to look at virtual memory for all 36 mongos. If there had been opLatency metrics available for the mongos, I feel confident I would have figured this out sooner." |