diff --git a/lib/config.go b/lib/config.go
index d250bdd4..e1b67efb 100644
--- a/lib/config.go
+++ b/lib/config.go
@@ -41,7 +41,7 @@ type Config struct {
 	NumStdbyDbs        int
 	InitialMaxChildren int
 	ReadonlyPct        int
-	TafPct 	   int
+	TafChildrenPct 	   int
 	//
 	// backlog
 	//
@@ -393,7 +393,7 @@ func InitConfig() error {
 	}
 
 	gAppConfig.ReadonlyPct = cdb.GetOrDefaultInt("readonly_children_pct", 0)
-	gAppConfig.TafPct = cdb.GetOrDefaultInt("taf_children_pct", 100)
+	gAppConfig.TafChildrenPct = cdb.GetOrDefaultInt("taf_children_pct", 100)
 	gAppConfig.InitialMaxChildren = numWorkers
 	if gAppConfig.EnableWhitelistTest {
 		if gAppConfig.NumWhitelistChildren < 2 {
@@ -644,15 +644,19 @@ func GetNumRWorkers(shard int) int {
 
 // GetNumStdByWorkers gets the number of workers for the "StdBy" pool
 func GetNumStdByWorkers(shard int) int {
-	numWhiteList := GetWhiteListChildCount(shard)
-	if numWhiteList > 0 {
-		return numWhiteList
+	num := GetNumWWorkers(shard)
+	// TafChildrenPct should not be greater than 100.
+	if gAppConfig.TafChildrenPct > 100 {
+		return num
 	}
-	num := GetNumWorkers(shard)
-	if gAppConfig.TafPct > 0 {
-		num = num * gAppConfig.TafPct / 100
-		if num == 0 {
+	if gAppConfig.EnableTAF && gAppConfig.TafChildrenPct < 100 {
+		if gAppConfig.TafChildrenPct < 0 {
 			num = 1
+		} else {
+			num = num * gAppConfig.TafChildrenPct / 100
+			if num == 0 {
+				num = 1
+			}
 		}
 	}
 	return num
diff --git a/tests/unittest/adjustTafChildrenPct/main_test.go b/tests/unittest/adjustTafChildrenPct/main_test.go
new file mode 100644
index 00000000..e32ac169
--- /dev/null
+++ b/tests/unittest/adjustTafChildrenPct/main_test.go
@@ -0,0 +1,102 @@
+package main
+
+import (
+	"context"
+	"database/sql"
+	"fmt"
+	"os"
+	"testing"
+	"time"
+
+	_ "github.com/paypal/hera/client/gosqldriver/tcp"
+	"github.com/paypal/hera/tests/unittest/testutil"
+	"github.com/paypal/hera/utility/logger"
+)
+
+var mx testutil.Mux
+//var tableName string
+
+func cfg() (map[string]string, map[string]string, testutil.WorkerType) {
+	fmt.Println ("setup() begin")
+	appcfg := make(map[string]string)
+	// best to chose an "unique" port in case golang runs tests in paralel
+	appcfg["bind_port"] = "31002"
+	appcfg["log_level"] = "5"
+	appcfg["log_file"] = "hera.log"
+	appcfg["enable_taf"] = "true"
+
+	appcfg["opscfg.default.server.max_connections"] = "10"
+
+	opscfg := make(map[string]string)
+	opscfg["opscfg.default.server.log_level"] = "5"
+
+	if os.Getenv("WORKER") == "postgres" {
+		return appcfg, opscfg, testutil.PostgresWorker
+	}
+	return appcfg, opscfg, testutil.MySQLWorker
+}
+
+func TestMain(m *testing.M) {
+	os.Exit(testutil.UtilMain(m, cfg, nil))
+}
+
+func TestAdjustTafChildrenPct(t *testing.T) {
+
+	logger.GetLogger().Log(logger.Debug, "TestAdjustTafChildrenPct begin +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++\n")
+
+	shard := 0
+	db, err := sql.Open("heraloop", fmt.Sprintf("%d:0:0", shard))
+	if err != nil {
+		t.Fatal("Error starting Mux:", err)
+		return
+	}
+	db.SetMaxIdleConns(0)
+	defer db.Close()
+
+	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+	defer cancel()
+	conn, err := db.Conn(ctx)
+	if err != nil {
+		t.Fatalf("Error getting connection %s\n", err.Error())
+	}
+	defer conn.Close()
+
+	rows, _ := conn.QueryContext(ctx, "SELECT version()")
+
+	if !rows.Next() {
+		t.Fatalf("Expected 1 row")
+	}
+	rows.Close()
+
+	acpt, err := testutil.StatelogGetField(2, "hera.taf")
+	if err != nil {
+		t.Fatalf("Error reading state log: %s\n", err.Error())
+	}
+
+	if acpt != 10 {
+		t.Fatalf("Expected TAF pool size: 10, Actual %d\n", acpt)
+	}
+
+	acpt, _ = testutil.StatelogGetField(2, " -v hera.taf")
+	if acpt != 5 {
+		t.Fatalf("Expected primary pool size: 10, Actual %d\n", acpt)
+	}
+
+	fmt.Println ("We now change max connections at runtime");
+	testutil.ModifyOpscfgParam (t, "hera.txt", "max_connections", "5")
+	//Wait for opsfcg change to take effect
+	time.Sleep(10 * time.Second)
+
+	acpt, _ = testutil.StatelogGetField(2, "hera.taf")
+
+	if acpt != 5 {
+		t.Fatalf("Expected TAF pool size: 5, Actual %d\n", acpt)
+	}
+
+	acpt, _ = testutil.StatelogGetField(2, " -v hera.taf")
+	if acpt != 5 {
+		t.Fatalf("Expected primary pool size: 5, Actual %d\n", acpt)
+	}
+
+	logger.GetLogger().Log(logger.Debug, "TestAdjustTafChildrenPct done  -------------------------------------------------------------")
+}
\ No newline at end of file
diff --git a/tests/unittest/adjustTafChildrenPctModified/main_test.go b/tests/unittest/adjustTafChildrenPctModified/main_test.go
new file mode 100644
index 00000000..371f5a83
--- /dev/null
+++ b/tests/unittest/adjustTafChildrenPctModified/main_test.go
@@ -0,0 +1,102 @@
+package main
+
+import (
+	"context"
+	"database/sql"
+	"fmt"
+	"os"
+	"testing"
+	"time"
+
+	_ "github.com/paypal/hera/client/gosqldriver/tcp"
+	"github.com/paypal/hera/tests/unittest/testutil"
+	"github.com/paypal/hera/utility/logger"
+)
+
+var mx testutil.Mux
+//var tableName string
+
+func cfg() (map[string]string, map[string]string, testutil.WorkerType) {
+	fmt.Println ("setup() begin")
+	appcfg := make(map[string]string)
+	// best to chose an "unique" port in case golang runs tests in paralel
+	appcfg["bind_port"] = "31002"
+	appcfg["log_level"] = "5"
+	appcfg["log_file"] = "hera.log"
+	appcfg["enable_taf"] = "true"
+	appcfg["taf_children_pct"] = "20"
+	appcfg["opscfg.default.server.max_connections"] = "10"
+
+	opscfg := make(map[string]string)
+	opscfg["opscfg.default.server.log_level"] = "5"
+
+	if os.Getenv("WORKER") == "postgres" {
+		return appcfg, opscfg, testutil.PostgresWorker
+	}
+	return appcfg, opscfg, testutil.MySQLWorker
+}
+
+func TestMain(m *testing.M) {
+	os.Exit(testutil.UtilMain(m, cfg, nil))
+}
+
+func TestAdjustTafChildrenPctModified(t *testing.T) {
+
+	logger.GetLogger().Log(logger.Debug, "TestAdjustTafChildrenPctModified begin +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++\n")
+
+	shard := 0
+	db, err := sql.Open("heraloop", fmt.Sprintf("%d:0:0", shard))
+	if err != nil {
+		t.Fatal("Error starting Mux:", err)
+		return
+	}
+	db.SetMaxIdleConns(0)
+	defer db.Close()
+
+	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+	defer cancel()
+	conn, err := db.Conn(ctx)
+	if err != nil {
+		t.Fatalf("Error getting connection %s\n", err.Error())
+	}
+	defer conn.Close()
+
+	rows, _ := conn.QueryContext(ctx, "SELECT version()")
+
+	if !rows.Next() {
+		t.Fatalf("Expected 1 row")
+	}
+	rows.Close()
+
+	acpt, err := testutil.StatelogGetField(2, "hera.taf")
+	if err != nil {
+		t.Fatalf("Error reading state log: %s\n", err.Error())
+	}
+
+	if acpt != 3 {
+		t.Fatalf("Expected TAF pool size: 2, Actual %d\n", acpt)
+	}
+
+	acpt, _ = testutil.StatelogGetField(2, " -v hera.taf")
+	if acpt != 5 {
+		t.Fatalf("Expected primary pool size: 10, Actual %d\n", acpt)
+	}
+
+	fmt.Println ("We now change max connections at runtime");
+	testutil.ModifyOpscfgParam (t, "hera.txt", "max_connections", "5")
+	//Wait for opsfcg change to take effect
+	time.Sleep(10 * time.Second)
+
+	acpt, _ = testutil.StatelogGetField(2, "hera.taf")
+
+	if acpt != 5 {
+		t.Fatalf("Expected TAF pool size: 1, Actual %d\n", acpt)
+	}
+
+	acpt, _ = testutil.StatelogGetField(2, " -v hera.taf")
+	if acpt != 5 {
+		t.Fatalf("Expected primary pool size: 5, Actual %d\n", acpt)
+	}
+
+	logger.GetLogger().Log(logger.Debug, "TestAdjustTafChildrenPctModified done  -------------------------------------------------------------")
+}
\ No newline at end of file
diff --git a/tests/unittest/adjustTafChildrenPctModifiedWithSharding/main_test.go b/tests/unittest/adjustTafChildrenPctModifiedWithSharding/main_test.go
new file mode 100644
index 00000000..2c605c02
--- /dev/null
+++ b/tests/unittest/adjustTafChildrenPctModifiedWithSharding/main_test.go
@@ -0,0 +1,114 @@
+package main
+
+import (
+	"fmt"
+	"os"
+	"testing"
+	"time"
+
+	_ "github.com/paypal/hera/client/gosqldriver/tcp"
+	"github.com/paypal/hera/tests/unittest/testutil"
+	"github.com/paypal/hera/utility/logger"
+)
+
+var mx testutil.Mux
+//var tableName string
+
+func cfg() (map[string]string, map[string]string, testutil.WorkerType) {
+	fmt.Println ("setup() begin")
+	appcfg := make(map[string]string)
+	// best to chose an "unique" port in case golang runs tests in paralel
+	appcfg["bind_port"] = "31002"
+	appcfg["log_level"] = "5"
+	appcfg["log_file"] = "hera.log"
+	appcfg["enable_taf"] = "true"
+	appcfg["taf_children_pct"] = "20"
+	appcfg["enable_sharding"] = "true"
+	appcfg["shard_key_name"] = "email_addr"
+	appcfg["shard_key_value_type_is_string"] = "true"
+	appcfg["num_shards"] = "2"
+	appcfg["sharding_cfg_reload_interval"] = "0"
+
+	appcfg["opscfg.default.server.max_connections"] = "10"
+
+	opscfg := make(map[string]string)
+	opscfg["opscfg.default.server.log_level"] = "5"
+
+	if os.Getenv("WORKER") == "postgres" {
+		return appcfg, opscfg, testutil.PostgresWorker
+	}
+	return appcfg, opscfg, testutil.MySQLWorker
+}
+
+func setupShardMap() {
+	testutil.RunDML("DROP TABLE IF EXISTS test_str_sk")
+	testutil.RunDML("create table test_str_sk (email_addr varchar(64), note varchar(64))")
+	testutil.RunDML("DROP TABLE IF EXISTS hera_shard_map")
+	testutil.RunDML("create table hera_shard_map ( scuttle_id smallint not null, shard_id smallint not null, status char(1) , read_status char(1), write_status char(1), remarks varchar(500))")
+	for i := 0; i < 1024; i++ {
+		testutil.RunDML(fmt.Sprintf("insert into hera_shard_map ( scuttle_id, shard_id, status, read_status, write_status ) values ( %d, 0, 'Y', 'Y', 'Y' )", i) )
+	}
+}
+
+func TestMain(m *testing.M) {
+	os.Exit(testutil.UtilMain(m, cfg, nil))
+}
+
+func TestAdjustTafChildrenPctWithSharding(t *testing.T) {
+	setupShardMap()
+	logger.GetLogger().Log(logger.Debug, "TestAdjustTafChildrenPctWithSharding begin +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++\n")
+
+	acpt, err := testutil.StatelogGetField(2, "hera.taf.sh0")
+	if err != nil {
+		t.Fatalf("Error reading state log: %s\n", err.Error())
+	}
+
+	if acpt != 2 {
+		t.Fatalf("Expected TAF sh0 pool size: 2, Actual %d\n", acpt)
+	}
+
+	acpt, _ = testutil.StatelogGetField(2, "hera.taf.sh1")
+
+	if acpt != 2 {
+		t.Fatalf("Expected TAF sh1 pool size: 2, Actual %d\n", acpt)
+	}
+
+	acpt, _ = testutil.StatelogGetField(2, " -v hera.sh0")
+	if acpt != 10 {
+		t.Fatalf("Expected primary pool sh0 size: 10, Actual %d\n", acpt)
+	}
+
+	acpt, _ = testutil.StatelogGetField(2, " -v hera.sh1")
+	if acpt != 10 {
+		t.Fatalf("Expected primary pool sh1 size: 10, Actual %d\n", acpt)
+	}
+
+	fmt.Println ("We now change max connections at runtime");
+	testutil.ModifyOpscfgParam (t, "hera.txt", "max_connections", "5")
+	//Wait for opsfcg change to take effect
+	time.Sleep(10 * time.Second)
+
+	acpt, _ = testutil.StatelogGetField(2, "hera.taf.sh0")
+
+	if acpt != 1 {
+		t.Fatalf("Expected TAF sh0 pool size: 1, Actual %d\n", acpt)
+	}
+
+	acpt, _ = testutil.StatelogGetField(2, "hera.taf.sh1")
+
+	if acpt != 1 {
+		t.Fatalf("Expected TAF sh1 pool size: 1, Actual %d\n", acpt)
+	}
+
+	acpt, _ = testutil.StatelogGetField(2, " -v hera.sh0")
+	if acpt != 5 {
+		t.Fatalf("Expected primary sh0 pool size: 5, Actual %d\n", acpt)
+	}
+
+	acpt, _ = testutil.StatelogGetField(2, " -v hera.sh1")
+	if acpt != 5 {
+		t.Fatalf("Expected primary sh1 pool size: 5, Actual %d\n", acpt)
+	}
+
+	logger.GetLogger().Log(logger.Debug, "TestAdjustTafChildrenPctWithSharding done  -------------------------------------------------------------")
+}
\ No newline at end of file
diff --git a/tests/unittest/testutil/setup.go b/tests/unittest/testutil/setup.go
index 795c78d0..6c365e03 100644
--- a/tests/unittest/testutil/setup.go
+++ b/tests/unittest/testutil/setup.go
@@ -360,9 +360,15 @@ func (m *mux) StartServer() error {
 			os.Setenv("username", "herausertest")
 			os.Setenv("password", "Hera-User-Test-9")
 			os.Setenv("TWO_TASK", "tcp(127.0.0.1:2121)/heratestdb")
+			os.Setenv("TWO_TASK_STANDBY0", "tcp(127.0.0.1:2121)/heratestdb")
+			os.Setenv("TWO_TASK_STANDBY0_0", "tcp(127.0.0.1:2121)/heratestdb")
+			os.Setenv("TWO_TASK_STANDBY0_1", "tcp(127.0.0.1:2121)/heratestdb")
 		} else if xMysql == "auto" {
 			ip := MakeDB("mysql22", "heratestdb", MySQL)
 			os.Setenv("TWO_TASK", "tcp("+ip+":3306)/heratestdb")
+			os.Setenv("TWO_TASK_STANDBY0", "tcp("+ip+":3306)/heratestdb")
+			os.Setenv("TWO_TASK_STANDBY0_0", "tcp("+ip+":3306)/heratestdb")
+			os.Setenv("TWO_TASK_STANDBY0_1", "tcp("+ip+":3306)/heratestdb")
 			os.Setenv("TWO_TASK_1", "tcp("+ip+":3306)/heratestdb")
 			os.Setenv("TWO_TASK_2", "tcp("+ip+":3306)/heratestdb")
 			os.Setenv("MYSQL_IP", ip)
diff --git a/tests/unittest/testutil/util.go b/tests/unittest/testutil/util.go
index 979ee4cb..b842a358 100644
--- a/tests/unittest/testutil/util.go
+++ b/tests/unittest/testutil/util.go
@@ -7,10 +7,12 @@ import (
 	"database/sql"
 	"errors"
 	"fmt"
+	"io/ioutil"
 	"os"
 	"os/exec"
 	"regexp"
 	"strings"
+	"testing"
 	"time"
 
 	"github.com/paypal/hera/utility/logger"
@@ -20,8 +22,13 @@ var (
 	INCOMPLETE = errors.New("Incomplete row")
 )
 
-func StatelogGetField(pos int) (int, error) {
-	out, err := exec.Command("/bin/bash", "-c", "/usr/bin/tail -n 1 state.log").Output()
+func StatelogGetField(pos int, pattern ...string) (int, error) {
+	cmd := "/usr/bin/tail -n 1 state.log"
+	if len(pattern) > 0 {
+		cmd = fmt.Sprintf("/usr/bin/tail -n 1 state.log | grep '%s'", pattern[0])
+		// fmt.Println("cmd:", cmd)
+	}
+	out, err := exec.Command("/bin/bash", "-c", cmd).Output()
 	if err != nil {
 		return -1, err
 	}
@@ -216,3 +223,24 @@ func ClearLogsData() {
 	}
 	defer calLogFile.Close()
 }
+
+func ModifyOpscfgParam (t *testing.T, logfile string, opscfg_param string, opscfg_value string) {
+	//Read file
+	data, err := ioutil.ReadFile(runFolder + "/" + logfile)
+	if err != nil {
+		t.Fatal(err)
+	}
+	lines := strings.Split(string(data), "\n")
+	//Modify the opcfg value
+	for i, line := range lines {
+		if strings.Contains(line, opscfg_param) {
+			lines[i] = "opscfg.default.server." + opscfg_param + "=" + opscfg_value
+		}
+	}
+	output := strings.Join(lines, "\n")
+	// write to file
+	err = ioutil.WriteFile(runFolder + "/" + logfile, []byte(output), 0644)
+	if err != nil {
+		t.Fatal(err)
+	}
+}