workload: increase burst for changefeed limiter

stevendanna · stevendanna · commit f95fe8560978 · 2025-11-03T14:53:27.000Z
The inbound work from the rangefeed is not evenly distributed over a 1s interval. For changefeeds, we mostly care about whether the configured rate is or is not sufficient for the given write rate over rather long time intervals. Using a large burst helps make we get the desired rate over those longer time horizons. Epic: CRDB-55203 Release note: none
diff --git a/pkg/workload/cli/run.go b/pkg/workload/cli/run.go
@@ -441,7 +441,9 @@ func runRun(gen workload.Generator, urls []string, dbName string) error {
 	}
 	var changefeedLimiter *rate.Limiter
 	if *changefeedMaxRate > 0 {
-		changefeedLimiter = rate.NewLimiter(rate.Limit(*changefeedMaxRate), 1)
+		ratePerSecond := *changefeedMaxRate
+		burst := max(int(ratePerSecond), 1)
+		changefeedLimiter = rate.NewLimiter(rate.Limit(ratePerSecond), burst)
 	}
 
 	maybeLogRandomSeed(ctx, gen)

Original file line number	Diff line number	Diff line change
`@@ -441,7 +441,9 @@ func runRun(gen workload.Generator, urls []string, dbName string) error {`
`441`	`441`	`}`
`442`	`442`	`var changefeedLimiter *rate.Limiter`
`443`	`443`	`if *changefeedMaxRate > 0 {`
`444`		`- changefeedLimiter = rate.NewLimiter(rate.Limit(*changefeedMaxRate), 1)`
	`444`	`+ ratePerSecond := *changefeedMaxRate`
	`445`	`+ burst := max(int(ratePerSecond), 1)`
	`446`	`+ changefeedLimiter = rate.NewLimiter(rate.Limit(ratePerSecond), burst)`
`445`	`447`	`}`
`446`	`448`
`447`	`449`	`maybeLogRandomSeed(ctx, gen)`