diff --git a/go/base/context.go b/go/base/context.go
index 51b43dfc8..b9badc43b 100644
--- a/go/base/context.go
+++ b/go/base/context.go
@@ -52,6 +52,7 @@ const (
 const (
 	HTTPStatusOK       = 200
 	MaxEventsBatchSize = 1000
+	ETAUnknown         = math.MinInt64
 )
 
 var (
@@ -182,6 +183,7 @@ type MigrationContext struct {
 	lastHeartbeatOnChangelogMutex          *sync.Mutex
 	CurrentLag                             int64
 	currentProgress                        uint64
+	etaNanoseonds                          int64
 	ThrottleHTTPStatusCode                 int64
 	controlReplicasLagResult               mysql.ReplicationLagResult
 	TotalRowsCopied                        int64
@@ -267,6 +269,7 @@ func NewMigrationContext() *MigrationContext {
 		MaxLagMillisecondsThrottleThreshold: 1500,
 		CutOverLockTimeoutSeconds:           3,
 		DMLBatchSize:                        10,
+		etaNanoseonds:                       ETAUnknown,
 		maxLoad:                             NewLoadMap(),
 		criticalLoad:                        NewLoadMap(),
 		throttleMutex:                       &sync.Mutex{},
@@ -474,6 +477,22 @@ func (this *MigrationContext) SetProgressPct(progressPct float64) {
 	atomic.StoreUint64(&this.currentProgress, math.Float64bits(progressPct))
 }
 
+func (this *MigrationContext) GetETADuration() time.Duration {
+	return time.Duration(atomic.LoadInt64(&this.etaNanoseonds))
+}
+
+func (this *MigrationContext) SetETADuration(etaDuration time.Duration) {
+	atomic.StoreInt64(&this.etaNanoseonds, etaDuration.Nanoseconds())
+}
+
+func (this *MigrationContext) GetETASeconds() int64 {
+	nano := atomic.LoadInt64(&this.etaNanoseonds)
+	if nano < 0 {
+		return ETAUnknown
+	}
+	return nano / int64(time.Second)
+}
+
 // math.Float64bits([f=0..100])
 
 // GetTotalRowsCopied returns the accurate number of rows being copied (affected)
diff --git a/go/logic/hooks.go b/go/logic/hooks.go
index 71f070ce3..2275ede51 100644
--- a/go/logic/hooks.go
+++ b/go/logic/hooks.go
@@ -66,6 +66,7 @@ func (this *HooksExecutor) applyEnvironmentVariables(extraVariables ...string) [
 	env = append(env, fmt.Sprintf("GH_OST_INSPECTED_LAG=%f", this.migrationContext.GetCurrentLagDuration().Seconds()))
 	env = append(env, fmt.Sprintf("GH_OST_HEARTBEAT_LAG=%f", this.migrationContext.TimeSinceLastHeartbeatOnChangelog().Seconds()))
 	env = append(env, fmt.Sprintf("GH_OST_PROGRESS=%f", this.migrationContext.GetProgressPct()))
+	env = append(env, fmt.Sprintf("GH_OST_ETA_SECONDS=%d", this.migrationContext.GetETASeconds()))
 	env = append(env, fmt.Sprintf("GH_OST_HOOKS_HINT=%s", this.migrationContext.HooksHintMessage))
 	env = append(env, fmt.Sprintf("GH_OST_HOOKS_HINT_OWNER=%s", this.migrationContext.HooksHintOwner))
 	env = append(env, fmt.Sprintf("GH_OST_HOOKS_HINT_TOKEN=%s", this.migrationContext.HooksHintToken))
diff --git a/go/logic/inspect.go b/go/logic/inspect.go
index 097b58f3a..fb473b830 100644
--- a/go/logic/inspect.go
+++ b/go/logic/inspect.go
@@ -187,6 +187,10 @@ func (this *Inspector) inspectOriginalAndGhostTables() (err error) {
 		if column.Name == mappedColumn.Name && column.Type == sql.DateTimeColumnType && mappedColumn.Type == sql.TimestampColumnType {
 			this.migrationContext.MappedSharedColumns.SetConvertDatetimeToTimestamp(column.Name, this.migrationContext.ApplierTimeZone)
 		}
+		if column.Name == mappedColumn.Name && column.Type == sql.EnumColumnType && mappedColumn.Charset != "" {
+			this.migrationContext.MappedSharedColumns.SetEnumToTextConversion(column.Name)
+			this.migrationContext.MappedSharedColumns.SetEnumValues(column.Name, column.EnumValues)
+		}
 	}
 
 	for _, column := range this.migrationContext.UniqueKey.Columns.Columns() {
@@ -590,6 +594,7 @@ func (this *Inspector) applyColumnTypes(databaseName, tableName string, columnsL
 			}
 			if strings.HasPrefix(columnType, "enum") {
 				column.Type = sql.EnumColumnType
+				column.EnumValues = sql.ParseEnumValues(m.GetString("COLUMN_TYPE"))
 			}
 			if strings.HasPrefix(columnType, "binary") {
 				column.Type = sql.BinaryColumnType
diff --git a/go/logic/migrator.go b/go/logic/migrator.go
index dfddccffc..c12c21fc3 100644
--- a/go/logic/migrator.go
+++ b/go/logic/migrator.go
@@ -939,20 +939,29 @@ func (this *Migrator) printStatus(rule PrintStatusRule, writers ...io.Writer) {
 	}
 
 	var etaSeconds float64 = math.MaxFloat64
-	eta := "N/A"
+	var etaDuration = time.Duration(base.ETAUnknown)
 	if progressPct >= 100.0 {
-		eta = "due"
+		etaDuration = 0
 	} else if progressPct >= 0.1 {
 		elapsedRowCopySeconds := this.migrationContext.ElapsedRowCopyTime().Seconds()
 		totalExpectedSeconds := elapsedRowCopySeconds * float64(rowsEstimate) / float64(totalRowsCopied)
 		etaSeconds = totalExpectedSeconds - elapsedRowCopySeconds
 		if etaSeconds >= 0 {
-			etaDuration := time.Duration(etaSeconds) * time.Second
-			eta = base.PrettifyDurationOutput(etaDuration)
+			etaDuration = time.Duration(etaSeconds) * time.Second
 		} else {
-			eta = "due"
+			etaDuration = 0
 		}
 	}
+	this.migrationContext.SetETADuration(etaDuration)
+	var eta string
+	switch etaDuration {
+	case 0:
+		eta = "due"
+	case time.Duration(base.ETAUnknown):
+		eta = "N/A"
+	default:
+		eta = base.PrettifyDurationOutput(etaDuration)
+	}
 
 	state := "migrating"
 	if atomic.LoadInt64(&this.migrationContext.CountingRowsFlag) > 0 && !this.migrationContext.ConcurrentCountTableRows {
diff --git a/go/logic/throttler.go b/go/logic/throttler.go
index d234ea663..abe8669e1 100644
--- a/go/logic/throttler.go
+++ b/go/logic/throttler.go
@@ -188,9 +188,12 @@ func (this *Throttler) collectControlReplicasLag() {
 		dbUri := connectionConfig.GetDBUri("information_schema")
 
 		var heartbeatValue string
-		if db, _, err := mysql.GetDB(this.migrationContext.Uuid, dbUri); err != nil {
+		db, _, err := mysql.GetDB(this.migrationContext.Uuid, dbUri)
+		if err != nil {
 			return lag, err
-		} else if err = db.QueryRow(replicationLagQuery).Scan(&heartbeatValue); err != nil {
+		}
+
+		if err := db.QueryRow(replicationLagQuery).Scan(&heartbeatValue); err != nil {
 			return lag, err
 		}
 
diff --git a/go/mysql/utils.go b/go/mysql/utils.go
index 17bb5fc32..43a228e18 100644
--- a/go/mysql/utils.go
+++ b/go/mysql/utils.go
@@ -18,8 +18,11 @@ import (
 	"github.com/outbrain/golib/sqlutils"
 )
 
-const MaxTableNameLength = 64
-const MaxReplicationPasswordLength = 32
+const (
+	MaxTableNameLength           = 64
+	MaxReplicationPasswordLength = 32
+	MaxDBPoolConnections         = 3
+)
 
 type ReplicationLagResult struct {
 	Key InstanceKey
@@ -39,23 +42,22 @@ func (this *ReplicationLagResult) HasLag() bool {
 var knownDBs map[string]*gosql.DB = make(map[string]*gosql.DB)
 var knownDBsMutex = &sync.Mutex{}
 
-func GetDB(migrationUuid string, mysql_uri string) (*gosql.DB, bool, error) {
+func GetDB(migrationUuid string, mysql_uri string) (db *gosql.DB, exists bool, err error) {
 	cacheKey := migrationUuid + ":" + mysql_uri
 
 	knownDBsMutex.Lock()
-	defer func() {
-		knownDBsMutex.Unlock()
-	}()
-
-	var exists bool
-	if _, exists = knownDBs[cacheKey]; !exists {
-		if db, err := gosql.Open("mysql", mysql_uri); err == nil {
-			knownDBs[cacheKey] = db
-		} else {
-			return db, exists, err
+	defer knownDBsMutex.Unlock()
+
+	if db, exists = knownDBs[cacheKey]; !exists {
+		db, err = gosql.Open("mysql", mysql_uri)
+		if err != nil {
+			return nil, false, err
 		}
+		db.SetMaxOpenConns(MaxDBPoolConnections)
+		db.SetMaxIdleConns(MaxDBPoolConnections)
+		knownDBs[cacheKey] = db
 	}
-	return knownDBs[cacheKey], exists, nil
+	return db, exists, nil
 }
 
 // GetReplicationLagFromSlaveStatus returns replication lag for a given db; via SHOW SLAVE STATUS
diff --git a/go/sql/builder.go b/go/sql/builder.go
index 776a10d70..7fe366c6f 100644
--- a/go/sql/builder.go
+++ b/go/sql/builder.go
@@ -38,6 +38,8 @@ func buildColumnsPreparedValues(columns *ColumnList) []string {
 		var token string
 		if column.timezoneConversion != nil {
 			token = fmt.Sprintf("convert_tz(?, '%s', '%s')", column.timezoneConversion.ToTimezone, "+00:00")
+		} else if column.enumToTextConversion {
+			token = fmt.Sprintf("ELT(?, %s)", column.EnumValues)
 		} else if column.Type == JSONColumnType {
 			token = "convert(? using utf8mb4)"
 		} else {
@@ -108,6 +110,8 @@ func BuildSetPreparedClause(columns *ColumnList) (result string, err error) {
 		var setToken string
 		if column.timezoneConversion != nil {
 			setToken = fmt.Sprintf("%s=convert_tz(?, '%s', '%s')", EscapeName(column.Name), column.timezoneConversion.ToTimezone, "+00:00")
+		} else if column.enumToTextConversion {
+			setToken = fmt.Sprintf("%s=ELT(?, %s)", EscapeName(column.Name), column.EnumValues)
 		} else if column.Type == JSONColumnType {
 			setToken = fmt.Sprintf("%s=convert(? using utf8mb4)", EscapeName(column.Name))
 		} else {
diff --git a/go/sql/parser.go b/go/sql/parser.go
index d9c0c3f19..eac0bdce3 100644
--- a/go/sql/parser.go
+++ b/go/sql/parser.go
@@ -33,6 +33,7 @@ var (
 		// ALTER TABLE tbl something
 		regexp.MustCompile(`(?i)\balter\s+table\s+([\S]+)\s+(.*$)`),
 	}
+	enumValuesRegexp = regexp.MustCompile("^enum[(](.*)[)]$")
 )
 
 type AlterTableParser struct {
@@ -205,3 +206,10 @@ func (this *AlterTableParser) HasExplicitTable() bool {
 func (this *AlterTableParser) GetAlterStatementOptions() string {
 	return this.alterStatementOptions
 }
+
+func ParseEnumValues(enumColumnType string) string {
+	if submatch := enumValuesRegexp.FindStringSubmatch(enumColumnType); len(submatch) > 0 {
+		return submatch[1]
+	}
+	return enumColumnType
+}
diff --git a/go/sql/parser_test.go b/go/sql/parser_test.go
index 6cdbb39cc..3157d097e 100644
--- a/go/sql/parser_test.go
+++ b/go/sql/parser_test.go
@@ -322,3 +322,21 @@ func TestParseAlterStatementExplicitTable(t *testing.T) {
 		test.S(t).ExpectTrue(reflect.DeepEqual(parser.alterTokens, []string{"drop column b", "add index idx(i)"}))
 	}
 }
+
+func TestParseEnumValues(t *testing.T) {
+	{
+		s := "enum('red','green','blue','orange')"
+		values := ParseEnumValues(s)
+		test.S(t).ExpectEquals(values, "'red','green','blue','orange'")
+	}
+	{
+		s := "('red','green','blue','orange')"
+		values := ParseEnumValues(s)
+		test.S(t).ExpectEquals(values, "('red','green','blue','orange')")
+	}
+	{
+		s := "zzz"
+		values := ParseEnumValues(s)
+		test.S(t).ExpectEquals(values, "zzz")
+	}
+}
diff --git a/go/sql/types.go b/go/sql/types.go
index fa6b74e4b..3c4ce5e85 100644
--- a/go/sql/types.go
+++ b/go/sql/types.go
@@ -33,15 +33,16 @@ type TimezoneConversion struct {
 }
 
 type Column struct {
-	Name       string
-	IsUnsigned bool
-	Charset    string
-	Type       ColumnType
-
+	Name                 string
+	IsUnsigned           bool
+	Charset              string
+	Type                 ColumnType
+	EnumValues           string
+	timezoneConversion   *TimezoneConversion
+	enumToTextConversion bool
 	// add Octet length for binary type, fix bytes with suffix "00" get clipped in mysql binlog.
 	// https://github.com/github/gh-ost/issues/909
-	BinaryOctetLength  uint
-	timezoneConversion *TimezoneConversion
+	BinaryOctetLength uint
 }
 
 func (this *Column) convertArg(arg interface{}, isUniqueKeyColumn bool) interface{} {
@@ -198,6 +199,18 @@ func (this *ColumnList) HasTimezoneConversion(columnName string) bool {
 	return this.GetColumn(columnName).timezoneConversion != nil
 }
 
+func (this *ColumnList) SetEnumToTextConversion(columnName string) {
+	this.GetColumn(columnName).enumToTextConversion = true
+}
+
+func (this *ColumnList) IsEnumToTextConversion(columnName string) bool {
+	return this.GetColumn(columnName).enumToTextConversion
+}
+
+func (this *ColumnList) SetEnumValues(columnName string, enumValues string) {
+	this.GetColumn(columnName).EnumValues = enumValues
+}
+
 func (this *ColumnList) String() string {
 	return strings.Join(this.Names(), ",")
 }
diff --git a/localtests/enum-to-varchar/create.sql b/localtests/enum-to-varchar/create.sql
new file mode 100644
index 000000000..0dbab17ed
--- /dev/null
+++ b/localtests/enum-to-varchar/create.sql
@@ -0,0 +1,26 @@
+drop table if exists gh_ost_test;
+create table gh_ost_test (
+  id int auto_increment,
+  i int not null,
+  e enum('red', 'green', 'blue', 'orange') null default null collate 'utf8_bin',
+  primary key(id)
+) auto_increment=1;
+
+insert into gh_ost_test values (null, 7, 'red');
+
+drop event if exists gh_ost_test;
+delimiter ;;
+create event gh_ost_test
+  on schedule every 1 second
+  starts current_timestamp
+  ends current_timestamp + interval 60 second
+  on completion not preserve
+  enable
+  do
+begin
+  insert into gh_ost_test values (null, 11, 'red');
+  insert into gh_ost_test values (null, 13, 'green');
+  insert into gh_ost_test values (null, 17, 'blue');
+  set @last_insert_id := last_insert_id();
+  update gh_ost_test set e='orange' where id = @last_insert_id;
+end ;;
diff --git a/localtests/enum-to-varchar/extra_args b/localtests/enum-to-varchar/extra_args
new file mode 100644
index 000000000..68524e49b
--- /dev/null
+++ b/localtests/enum-to-varchar/extra_args
@@ -0,0 +1 @@
+--alter="change e e varchar(32) not null default ''"