diff --git a/hrp/boomer.go b/hrp/boomer.go
index 1761169c..9a1d20fa 100644
--- a/hrp/boomer.go
+++ b/hrp/boomer.go
@@ -95,27 +95,27 @@ func (b *HRPBoomer) convertBoomerTask(testcase *TestCase, rendezvousList []*Rend
 		Name:   config.Name,
 		Weight: config.Weight,
 		Fn: func() {
-			sessionRunner := hrpRunner.NewSessionRunner(testcase)
+			sessionTestCase := &TestCase{}
+			// copy testcase to avoid data racing
+			if err := copier.Copy(sessionTestCase, testcase); err != nil {
+				log.Error().Err(err).Msg("copy testcase data failed")
+				return
+			}
+			sessionRunner := hrpRunner.NewSessionRunner(sessionTestCase)
 			sessionRunner.parser.plugin = plugin
 
 			testcaseSuccess := true       // flag whole testcase result
 			var transactionSuccess = true // flag current transaction result
 
-			cfg := testcase.Config
-			caseConfig := &TConfig{}
-			// copy config to avoid data racing
-			if err := copier.Copy(caseConfig, cfg); err != nil {
-				log.Error().Err(err).Msg("copy config data failed")
-				return
-			}
+			cfg := sessionTestCase.Config
 			// iterate through all parameter iterators and update case variables
-			for _, it := range caseConfig.ParametersSetting.Iterators {
+			for _, it := range cfg.ParametersSetting.Iterators {
 				if it.HasNext() {
-					caseConfig.Variables = mergeVariables(it.Next(), caseConfig.Variables)
+					cfg.Variables = mergeVariables(it.Next(), cfg.Variables)
 				}
 			}
 
-			if err := sessionRunner.parseConfig(caseConfig); err != nil {
+			if err := sessionRunner.parseConfig(cfg); err != nil {
 				log.Error().Err(err).Msg("parse config failed")
 				return
 			}
diff --git a/hrp/config.go b/hrp/config.go
index 5af9ae87..7a3683fd 100644
--- a/hrp/config.go
+++ b/hrp/config.go
@@ -177,7 +177,7 @@ type iteratorStrategyType string
 
 const (
 	strategyRandom     iteratorStrategyType = "random"
-	strategySequential iteratorStrategyType = "Sequential"
+	strategySequential iteratorStrategyType = "sequential"
 )
 
 type iteratorParamsType []map[string]interface{}
diff --git a/hrp/parser.go b/hrp/parser.go
index 4a8126a3..3a7ea231 100644
--- a/hrp/parser.go
+++ b/hrp/parser.go
@@ -652,7 +652,7 @@ func initParameterIterator(cfg *TConfig, mode string) (err error) {
 				// use strategy if configured
 				cfg.ParametersSetting.Iterators = append(
 					cfg.ParametersSetting.Iterators,
-					newIterator(v, rawValue.MapIndex(reflect.ValueOf(k)).Interface().(iteratorStrategyType), cfg.ParametersSetting.Iteration),
+					newIterator(v, iteratorStrategyType(rawValue.MapIndex(reflect.ValueOf(k)).String()), cfg.ParametersSetting.Iteration),
 				)
 			} else {
 				// use sequential strategy by default
@@ -667,7 +667,7 @@ func initParameterIterator(cfg *TConfig, mode string) (err error) {
 		if len(rawValue.String()) == 0 {
 			cfg.ParametersSetting.Strategy = strategySequential
 		} else {
-			cfg.ParametersSetting.Strategy = strings.ToLower(rawValue.String())
+			cfg.ParametersSetting.Strategy = iteratorStrategyType(strings.ToLower(rawValue.String()))
 		}
 		cfg.ParametersSetting.Iterators = append(
 			cfg.ParametersSetting.Iterators,