diff --git a/.devcontainer/devcontainer.json b/.devcontainer/devcontainer.json
index 1bce9d2..8173c52 100644
--- a/.devcontainer/devcontainer.json
+++ b/.devcontainer/devcontainer.json
@@ -1,50 +1,45 @@
 // For format details, see https://aka.ms/devcontainer.json. For config options, see the README at:
 // https://github.com/microsoft/vscode-dev-containers/tree/v0.154.2/containers/go
 {
-	"name": "Go",
-	"dockerComposeFile": "./docker-compose.yaml",
-	"service": "jobrunner_code",
-	"shutdownAction": "stopCompose",
+  "name": "Go",
+  "dockerComposeFile": "./docker-compose.yaml",
+  "service": "jobrunner_code",
+  "shutdownAction": "stopCompose",
 
-	// Set *default* container specific settings.json values on container create.
-	"settings": {
-		"terminal.integrated.shell.linux": "/bin/bash",
-		"go.toolsManagement.checkForUpdates": "local",
-		"go.useLanguageServer": true,
-		"go.gopath": "/go",
-		"go.goroot": "/usr/local/go",
-		"go.toolsGopath": "/go/bin",
-		"go.buildOnSave": "package",
-		"go.testOnSave": true,
-		"go.coverOnTestPackage": true,
-		"go.coverageDecorator": {
-			"type": "gutter",
-			"coveredHighlightColor": "rgba(64,128,128,0.5)",
-			"uncoveredHighlightColor": "rgba(128,64,64,0.25)",
-			"coveredGutterStyle": "blockgreen",
-			"uncoveredGutterStyle": "blockred"
-		},
-		"go.coverOnSingleTest": true,
-		"go.coverOnSave": true,
-		"go.testFlags": ["-short"]
-	},
+  // Set *default* container specific settings.json values on container create.
+  "settings": {
+    "go.toolsManagement.checkForUpdates": "local",
+    "go.useLanguageServer": true,
+    "go.gopath": "/go",
+    "go.goroot": "/usr/local/go",
+    "go.toolsGopath": "/go/bin",
+    "go.buildOnSave": "package",
+    "go.testOnSave": true,
+    "go.coverOnTestPackage": true,
+    "go.coverageDecorator": {
+      "type": "gutter",
+      "coveredHighlightColor": "rgba(64,128,128,0.5)",
+      "uncoveredHighlightColor": "rgba(128,64,64,0.25)",
+      "coveredGutterStyle": "blockgreen",
+      "uncoveredGutterStyle": "blockred"
+    },
+    "go.coverOnSingleTest": true,
+    "go.coverOnSave": true,
+    "go.testFlags": ["-short"]
+  },
 
-	// Mount to proper location
-	"workspaceFolder": "/go/src/github.com/zhongjie-cai/job-runner",
+  // Mount to proper location
+  "workspaceFolder": "/go/src/github.com/zhongjie-cai/job-runner",
 
-	// Add the IDs of extensions you want installed when the container is created.
-	"extensions": [
-		"golang.Go",
-		"eamodio.gitlens",
-		"yzhang.markdown-all-in-one"
-	],
+  // Add the IDs of extensions you want installed when the container is created.
+  "extensions": ["golang.Go", "eamodio.gitlens", "yzhang.markdown-all-in-one"]
 
-	// Use 'forwardPorts' to make a list of ports inside the container available locally.
-	// "forwardPorts": [],
+  // Use 'forwardPorts' to make a list of ports inside the container available locally.
+  // "forwardPorts": [],
 
-	// Use 'postCreateCommand' to run commands after the container is created.
-	// "postCreateCommand": "go version",
+  // Use 'postCreateCommand' to run commands after the container is created.
+  // "postCreateCommand": "go version",
 
-	// Comment out connect as root instead. More info: https://aka.ms/vscode-remote/containers/non-root.
-	//"remoteUser": "vscode"
+  // Comment out connect as root instead. More info: https://aka.ms/vscode-remote/containers/non-root.
+  //"remoteUser": "vscode"
 }
diff --git a/0_functionPointers.go b/0_functionPointers.go
index 064f3b9..f82be15 100644
--- a/0_functionPointers.go
+++ b/0_functionPointers.go
@@ -8,9 +8,7 @@ import (
 	"net/http"
 	"net/url"
 	"reflect"
-	"regexp"
 	"runtime"
-	"runtime/debug"
 	"sort"
 	"strconv"
 	"strings"
@@ -44,7 +42,6 @@ var (
 	fmtPrintf              = fmt.Printf
 	fmtSprintf             = fmt.Sprintf
 	marshalIgnoreErrorFunc = marshalIgnoreError
-	debugStack             = debug.Stack
 )
 
 // func pointers for injection / testing: handler.go
@@ -88,11 +85,6 @@ var (
 	stringsJoin = strings.Join
 )
 
-// func pointers for injection / testing: parameter.go
-var (
-	regexpMatchString = regexp.MatchString
-)
-
 // func pointers for injection / testing: pointerutil.go
 var (
 	reflectValueOf = reflect.ValueOf
diff --git a/0_functionPointers_test.go b/0_functionPointers_test.go
index cb74305..ec7b549 100644
--- a/0_functionPointers_test.go
+++ b/0_functionPointers_test.go
@@ -10,9 +10,7 @@ import (
 	"net/http"
 	"net/url"
 	"reflect"
-	"regexp"
 	"runtime"
-	"runtime/debug"
 	"sort"
 	"strconv"
 	"strings"
@@ -62,8 +60,6 @@ var (
 	fmtSprintfCalled                       int
 	marshalIgnoreErrorFuncExpected         int
 	marshalIgnoreErrorFuncCalled           int
-	debugStackExpected                     int
-	debugStackCalled                       int
 	stringsSplitExpected                   int
 	stringsSplitCalled                     int
 	strconvAtoiExpected                    int
@@ -104,8 +100,6 @@ var (
 	sortStringsCalled                      int
 	stringsJoinExpected                    int
 	stringsJoinCalled                      int
-	regexpMatchStringExpected              int
-	regexpMatchStringCalled                int
 	reflectValueOfExpected                 int
 	reflectValueOfCalled                   int
 	timeDateExpected                       int
@@ -144,8 +138,6 @@ var (
 	ioutilNopCloserCalled                  int
 	bytesNewBufferExpected                 int
 	bytesNewBufferCalled                   int
-	constructResponseFuncExpected          int
-	constructResponseFuncCalled            int
 	logProcessEnterFuncExpected            int
 	logProcessEnterFuncCalled              int
 	logProcessExitFuncExpected             int
@@ -276,7 +268,7 @@ func createMock(t *testing.T) {
 	}
 	handleSessionFuncExpected = 0
 	handleSessionFuncCalled = 0
-	handleSessionFunc = func(app *application, index int) error {
+	handleSessionFunc = func(app *application, index int, reruns int) error {
 		handleSessionFuncCalled++
 		return nil
 	}
@@ -329,12 +321,6 @@ func createMock(t *testing.T) {
 		marshalIgnoreErrorFuncCalled++
 		return ""
 	}
-	debugStackExpected = 0
-	debugStackCalled = 0
-	debugStack = func() []byte {
-		debugStackCalled++
-		return nil
-	}
 	stringsSplitExpected = 0
 	stringsSplitCalled = 0
 	stringsSplit = func(s, sep string) []string {
@@ -349,7 +335,7 @@ func createMock(t *testing.T) {
 	}
 	initiateSessionFuncExpected = 0
 	initiateSessionFuncCalled = 0
-	initiateSessionFunc = func(app *application, index int) *session {
+	initiateSessionFunc = func(app *application, index int, reruns int) *session {
 		initiateSessionFuncCalled++
 		return nil
 	}
@@ -453,12 +439,6 @@ func createMock(t *testing.T) {
 		stringsJoinCalled++
 		return ""
 	}
-	regexpMatchStringExpected = 0
-	regexpMatchStringCalled = 0
-	regexpMatchString = func(pattern string, s string) (bool, error) {
-		regexpMatchStringCalled++
-		return false, nil
-	}
 	reflectValueOfExpected = 0
 	reflectValueOfCalled = 0
 	reflectValueOf = func(i interface{}) reflect.Value {
@@ -825,8 +805,6 @@ func verifyAll(t *testing.T) {
 	assert.Equal(t, fmtSprintfExpected, fmtSprintfCalled, "Unexpected number of calls to method fmtSprintf")
 	marshalIgnoreErrorFunc = marshalIgnoreError
 	assert.Equal(t, marshalIgnoreErrorFuncExpected, marshalIgnoreErrorFuncCalled, "Unexpected number of calls to method marshalIgnoreErrorFunc")
-	debugStack = debug.Stack
-	assert.Equal(t, debugStackExpected, debugStackCalled, "Unexpected number of calls to debugStack")
 	stringsSplit = strings.Split
 	assert.Equal(t, stringsSplitExpected, stringsSplitCalled, "Unexpected number of calls to method stringsSplit")
 	strconvAtoi = strconv.Atoi
@@ -867,8 +845,6 @@ func verifyAll(t *testing.T) {
 	assert.Equal(t, sortStringsExpected, sortStringsCalled, "Unexpected number of calls to sortStrings")
 	stringsJoin = strings.Join
 	assert.Equal(t, stringsJoinExpected, stringsJoinCalled, "Unexpected number of calls to stringsJoin")
-	regexpMatchString = regexp.MatchString
-	assert.Equal(t, regexpMatchStringExpected, regexpMatchStringCalled, "Unexpected number of calls to regexpMatchString")
 	reflectValueOf = reflect.ValueOf
 	assert.Equal(t, reflectValueOfExpected, reflectValueOfCalled, "Unexpected number of calls to reflectValueOf")
 	timeDate = time.Date
@@ -1074,6 +1050,11 @@ func (session *dummySession) GetIndex() int {
 	return 0
 }
 
+func (session *dummySession) GetReruns() int {
+	assert.Fail(session.t, "Unexpected call to GetReruns")
+	return 0
+}
+
 func (session *dummySession) Attach(name string, value interface{}) bool {
 	assert.Fail(session.t, "Unexpected call to Attach")
 	return false
diff --git a/application.go b/application.go
index d208e4e..cc593b8 100644
--- a/application.go
+++ b/application.go
@@ -2,6 +2,7 @@ package jobrunner
 
 import (
 	"sync"
+	"sync/atomic"
 )
 
 // Application is the interface for job runner application
@@ -20,6 +21,7 @@ type application struct {
 	name          string
 	version       string
 	instances     int
+	reruns        []int32
 	schedule      Schedule
 	overlap       bool
 	session       *session
@@ -27,6 +29,7 @@ type application struct {
 	shutdown      chan bool
 	started       bool
 	lastErrors    []error
+	waits         sync.WaitGroup
 }
 
 // NewApplication creates a new application for job runner hosting
@@ -45,21 +48,23 @@ func NewApplication(
 		customization = customizationDefault
 	}
 	var application = &application{
-		name,
-		version,
-		instances,
-		schedule,
-		overlap,
-		&session{
-			uuidNew(),
-			0,
-			map[string]interface{}{},
-			customization,
+		name:      name,
+		version:   version,
+		instances: instances,
+		reruns:    make([]int32, instances),
+		schedule:  schedule,
+		overlap:   overlap,
+		session: &session{
+			id:            uuidNew(),
+			index:         0,
+			attachment:    map[string]interface{}{},
+			customization: customization,
 		},
-		customization,
-		make(chan bool),
-		false,
-		[]error{},
+		customization: customization,
+		shutdown:      make(chan bool),
+		started:       false,
+		lastErrors:    []error{},
+		waits:         sync.WaitGroup{},
 	}
 	return application
 }
@@ -197,10 +202,12 @@ func runInstances(app *application) {
 	var waitGroup sync.WaitGroup
 	for id := 0; id < app.instances; id++ {
 		waitGroup.Add(1)
-		go func(index int) {
+		atomic.AddInt32(&app.reruns[id], 1)
+		go func(index int, reruns int) {
 			var sessionError = handleSessionFunc(
 				app,
 				index,
+				reruns,
 			)
 			if sessionError != nil {
 				app.lastErrors = append(
@@ -209,9 +216,12 @@ func runInstances(app *application) {
 				)
 			}
 			waitGroup.Done()
-		}(id)
+		}(id, int(app.reruns[id]))
 	}
 	waitGroup.Wait()
+	if app.overlap {
+		app.waits.Done()
+	}
 }
 
 func scheduleExecution(app *application) {
@@ -223,6 +233,7 @@ func scheduleExecution(app *application) {
 			break
 		}
 		if app.overlap {
+			app.waits.Add(1)
 			go runInstancesFunc(
 				app,
 			)
@@ -232,6 +243,9 @@ func scheduleExecution(app *application) {
 			)
 		}
 	}
+	if app.overlap {
+		app.waits.Wait()
+	}
 }
 
 func runApplication(app *application) {
diff --git a/application_test.go b/application_test.go
index 3066ab6..7625f4a 100644
--- a/application_test.go
+++ b/application_test.go
@@ -17,7 +17,7 @@ func TestNewApplication_NilCustomization(t *testing.T) {
 	// arrange
 	var dummyName = "some name"
 	var dummyVersion = "some version"
-	var dummyInstances = rand.Int()
+	var dummyInstances = rand.Intn(100)
 	var dummySchedule Schedule
 	var dummyOverlap = rand.Intn(100) > 50
 	var dummyCustomization Customization
@@ -75,7 +75,7 @@ func TestNewApplication_HasCustomization(t *testing.T) {
 	// arrange
 	var dummyName = "some name"
 	var dummyVersion = "some version"
-	var dummyInstances = rand.Int()
+	var dummyInstances = rand.Intn(100)
 	var dummySchedule Schedule
 	var dummyOverlap = rand.Intn(100) > 50
 	var dummyCustomization = &dummyCustomization{t: t}
@@ -834,8 +834,10 @@ func TestRunInstances_ZeroInstance(t *testing.T) {
 
 func TestRunInstances_SingleInstance(t *testing.T) {
 	// arrange
+	var dummyReruns = rand.Int31n(65535)
 	var dummyApplication = &application{
 		instances: 1,
+		reruns:    []int32{dummyReruns},
 	}
 	var dummyError = errors.New("some error")
 
@@ -844,10 +846,11 @@ func TestRunInstances_SingleInstance(t *testing.T) {
 
 	// expect
 	handleSessionFuncExpected = 1
-	handleSessionFunc = func(app *application, index int) error {
+	handleSessionFunc = func(app *application, index int, reruns int) error {
 		handleSessionFuncCalled++
 		assert.Equal(t, dummyApplication, app)
 		assert.Equal(t, 0, index)
+		assert.Equal(t, int(dummyReruns)+1, reruns)
 		return dummyError
 	}
 
@@ -873,6 +876,7 @@ func TestRunInstances_MultipleInstances(t *testing.T) {
 	}
 	var dummyApplication = &application{
 		instances: len(dummyErrors),
+		reruns:    make([]int32, len(dummyErrors)),
 	}
 	var expectedIndex = map[int]bool{}
 	var writeLock sync.Mutex
@@ -882,7 +886,7 @@ func TestRunInstances_MultipleInstances(t *testing.T) {
 
 	// expect
 	handleSessionFuncExpected = dummyApplication.instances
-	handleSessionFunc = func(app *application, index int) error {
+	handleSessionFunc = func(app *application, index int, reruns int) error {
 		handleSessionFuncCalled++
 		assert.Equal(t, dummyApplication, app)
 		writeLock.Lock()
@@ -908,6 +912,45 @@ func TestRunInstances_MultipleInstances(t *testing.T) {
 	verifyAll(t)
 }
 
+func TestRunInstances_Overlap(t *testing.T) {
+	// arrange
+	var dummyReruns = rand.Int31n(65535)
+	var dummyApplication = &application{
+		instances: 1,
+		reruns:    []int32{dummyReruns},
+		overlap:   true,
+	}
+	var dummyError = errors.New("some error")
+
+	// stub
+	dummyApplication.waits.Add(1)
+
+	// mock
+	createMock(t)
+
+	// expect
+	handleSessionFuncExpected = 1
+	handleSessionFunc = func(app *application, index int, reruns int) error {
+		handleSessionFuncCalled++
+		assert.Equal(t, dummyApplication, app)
+		assert.Equal(t, 0, index)
+		assert.Equal(t, int(dummyReruns)+1, reruns)
+		return dummyError
+	}
+
+	// SUT + act
+	runInstances(
+		dummyApplication,
+	)
+
+	// assert
+	assert.Equal(t, 1, len(dummyApplication.lastErrors))
+	assert.Equal(t, dummyError, dummyApplication.lastErrors[0])
+
+	// verify
+	verifyAll(t)
+}
+
 func TestScheduleExecution_WithOverlap(t *testing.T) {
 	// arrange
 	var dummyApplication = &application{
diff --git a/handler.go b/handler.go
index 7b7f7fe..d114450 100644
--- a/handler.go
+++ b/handler.go
@@ -7,12 +7,14 @@ import (
 func initiateSession(
 	app *application,
 	index int,
+	reruns int,
 ) *session {
 	return &session{
-		uuidNew(),
-		index,
-		map[string]interface{}{},
-		app.customization,
+		id:            uuidNew(),
+		index:         index,
+		reruns:        reruns,
+		attachment:    map[string]interface{}{},
+		customization: app.customization,
 	}
 }
 
@@ -64,10 +66,12 @@ func processSession(
 func handleSession(
 	app *application,
 	index int,
+	reruns int,
 ) (err error) {
 	var session = initiateSessionFunc(
 		app,
 		index,
+		reruns,
 	)
 	logProcessEnterFunc(
 		session,
diff --git a/handler_test.go b/handler_test.go
index 464f97a..5fbc923 100644
--- a/handler_test.go
+++ b/handler_test.go
@@ -17,6 +17,7 @@ func TestInitiateSession(t *testing.T) {
 		customization: dummyCustomization,
 	}
 	var dummyIndex = rand.Intn(65536)
+	var dummyReruns = rand.Intn(65536)
 	var dummySessionID = uuid.New()
 
 	// mock
@@ -33,12 +34,14 @@ func TestInitiateSession(t *testing.T) {
 	var session = initiateSession(
 		dummyApplication,
 		dummyIndex,
+		dummyReruns,
 	)
 
 	// assert
 	assert.NotNil(t, session)
 	assert.Equal(t, dummySessionID, session.id)
 	assert.Equal(t, dummyIndex, session.index)
+	assert.Equal(t, dummyReruns, session.reruns)
 	assert.Empty(t, session.attachment)
 	assert.Equal(t, dummyCustomization, session.customization)
 
@@ -384,6 +387,7 @@ func TestHandleSession_HappyPath(t *testing.T) {
 		customization: dummyCustomization,
 	}
 	var dummyIndex = rand.Int()
+	var dummyReruns = rand.Int()
 	var dummySession = &session{id: uuid.New()}
 	var dummyTimeNow = time.Now()
 	var dummyDuration = time.Duration(rand.Intn(100))
@@ -395,10 +399,11 @@ func TestHandleSession_HappyPath(t *testing.T) {
 
 	// expect
 	initiateSessionFuncExpected = 1
-	initiateSessionFunc = func(app *application, index int) *session {
+	initiateSessionFunc = func(app *application, index int, reruns int) *session {
 		initiateSessionFuncCalled++
 		assert.Equal(t, dummyApplication, app)
 		assert.Equal(t, dummyIndex, index)
+		assert.Equal(t, dummyReruns, reruns)
 		return dummySession
 	}
 	logProcessEnterFuncExpected = 1
@@ -471,6 +476,7 @@ func TestHandleSession_HappyPath(t *testing.T) {
 	var err = handleSession(
 		dummyApplication,
 		dummyIndex,
+		dummyReruns,
 	)
 
 	// assert
diff --git a/jsonutil.go b/jsonutil.go
index a3d92f7..04e9d70 100644
--- a/jsonutil.go
+++ b/jsonutil.go
@@ -20,7 +20,7 @@ func marshalIgnoreError(v interface{}) string {
 	var encoder = jsonNewEncoder(buffer)
 	encoder.SetEscapeHTML(false)
 	encoder.Encode(v)
-	var result = string(buffer.Bytes())
+	var result = buffer.String()
 	return stringsTrimRight(result, "\n")
 }
 
diff --git a/logType.go b/logType.go
index 492a2ef..f765258 100644
--- a/logType.go
+++ b/logType.go
@@ -1,9 +1,5 @@
 package jobrunner
 
-import (
-	"strings"
-)
-
 // LogType is the entry type of logging
 type LogType int
 
@@ -148,7 +144,7 @@ func (logtype LogType) HasFlag(flag LogType) bool {
 
 // NewLogType converts a string representation of LogType flag to its strongly typed instance
 func NewLogType(value string) LogType {
-	var splitValues = strings.Split(
+	var splitValues = stringsSplit(
 		value,
 		"|",
 	)
diff --git a/scheduleMaker.go b/scheduleMaker.go
index 732444f..ffe4225 100644
--- a/scheduleMaker.go
+++ b/scheduleMaker.go
@@ -474,7 +474,7 @@ func determineScheduleIndex(
 			),
 			nil
 	}
-	schedule.second, schedule.secondIndex, increment, overflow = findValueMatchFunc(
+	schedule.second, schedule.secondIndex, _, overflow = findValueMatchFunc(
 		start.Second(),
 		schedule.seconds,
 	)
diff --git a/session.go b/session.go
index d07a3fb..d75f2a8 100644
--- a/session.go
+++ b/session.go
@@ -19,6 +19,9 @@ type SessionMeta interface {
 
 	// GetIndex returns the instance index registered to session object for given session ID
 	GetIndex() int
+
+	// GetReruns returns the rerun count for the same instance since first scheduled
+	GetReruns() int
 }
 
 // SessionAttachment is a subset of Session interface, containing only attachment related methods
@@ -63,6 +66,7 @@ type SessionWebcall interface {
 type session struct {
 	id            uuid.UUID
 	index         int
+	reruns        int
 	attachment    map[string]interface{}
 	customization Customization
 }
@@ -83,6 +87,14 @@ func (session *session) GetIndex() int {
 	return session.index
 }
 
+// GetReruns returns the rerun count for the same instance since first scheduled
+func (session *session) GetReruns() int {
+	if session == nil {
+		return 0
+	}
+	return session.reruns
+}
+
 // Attach attaches any value object into the given session associated to the session ID
 func (session *session) Attach(name string, value interface{}) bool {
 	if session == nil {