VReplication: Estimate lag when workflow fully throttled (#16577) #178
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) Signed-off-by: Matt Lord <[email protected]>
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Pull Request Overview
This PR implements lag estimation for VReplication workflows when they are fully throttled, ensuring that lag metrics remain accurate even during throttling periods.
- Removes the timer-based heartbeat injection during throttling in vstreamer
- Adds lag estimation functionality when throttled heartbeat events are encountered
- Updates test helper functions to validate throttling behavior and lag calculation
Reviewed Changes
Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.
| File | Description |
|---|---|
| go/vt/vttablet/tabletserver/vstreamer/vstreamer.go | Simplifies throttling logic by removing timer-based heartbeats and improving logging |
| go/vt/vttablet/tabletmanager/vreplication/vplayer.go | Adds lag estimation function and filters out throttled heartbeats from lag calculations |
| go/test/endtoend/vreplication/vreplication_test.go | Refactors test helpers into reusable function for validating VReplication throttling metrics |
| estimateLag := func() { | ||
| behind := time.Now().UnixNano() - vp.lastTimestampNs - vp.timeOffsetNs | ||
| vp.vr.stats.ReplicationLagSeconds.Store(behind / 1e9) | ||
| vp.vr.stats.VReplicationLags.Add(strconv.Itoa(int(vp.vr.id)), time.Duration(behind/1e9)*time.Second) |
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The lag calculation behind / 1e9 is repeated twice. Consider storing this value in a variable to avoid duplication and improve readability.
| vp.vr.stats.VReplicationLags.Add(strconv.Itoa(int(vp.vr.id)), time.Duration(behind/1e9)*time.Second) | |
| lagSecs := behind / 1e9 | |
| vp.vr.stats.ReplicationLagSeconds.Store(lagSecs) | |
| vp.vr.stats.VReplicationLags.Add(strconv.Itoa(int(vp.vr.id)), time.Duration(lagSecs)*time.Second) |
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| // If the batch consists only of throttled heartbeat events then we cannot | ||
| // determine the actual lag, as the vstreamer is fully throttled, and we | ||
| // will estimate it after processing the batch. | ||
| if !(event.Type == binlogdatapb.VEventType_HEARTBEAT && event.Throttled) { |
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[nitpick] Consider extracting this condition into a named function like isThrottledHeartbeat(event) to improve readability and make the logic more explicit.
| if !(event.Type == binlogdatapb.VEventType_HEARTBEAT && event.Throttled) { | |
| if !isThrottledHeartbeat(event) { |
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This is a backport for vitessio#16577
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