diff --git a/kvs/boltdb/tx.go b/kvs/boltdb/tx.go
index e1b03f68..82b0d3c6 100644
--- a/kvs/boltdb/tx.go
+++ b/kvs/boltdb/tx.go
@@ -28,6 +28,7 @@ import (
 // TX is a distributed database transaction.
 type TX struct {
 	ds *DS
+	do bool
 	ck []byte
 	tx *bolt.Tx
 	bu *bolt.Bucket
@@ -329,6 +330,10 @@ func (tx *TX) RDel(beg, end []byte, max uint64) (err error) {
 
 }
 
+func (tx *TX) Done() (val bool) {
+	return tx.do
+}
+
 func (tx *TX) Close() (err error) {
 	return tx.Rollback()
 }
@@ -338,6 +343,7 @@ func (tx *TX) Cancel() (err error) {
 }
 
 func (tx *TX) Commit() (err error) {
+	tx.do = true
 	if tx.tx.Writable() {
 		return tx.tx.Commit()
 	}
@@ -345,6 +351,7 @@ func (tx *TX) Commit() (err error) {
 }
 
 func (tx *TX) Rollback() (err error) {
+	tx.do = true
 	return tx.tx.Rollback()
 }
 
diff --git a/kvs/mysql/tx.go b/kvs/mysql/tx.go
index 31fffc56..0d106ed3 100644
--- a/kvs/mysql/tx.go
+++ b/kvs/mysql/tx.go
@@ -28,6 +28,7 @@ import (
 // TX is a distributed database transaction.
 type TX struct {
 	ds *DS
+	do bool
 	ck []byte
 	tx *sql.Tx
 }
@@ -310,6 +311,10 @@ func (tx *TX) RDel(beg, end []byte, max uint64) (err error) {
 
 }
 
+func (tx *TX) Done() (val bool) {
+	return tx.do
+}
+
 func (tx *TX) Close() (err error) {
 	return tx.Rollback()
 }
@@ -319,10 +324,12 @@ func (tx *TX) Cancel() (err error) {
 }
 
 func (tx *TX) Commit() (err error) {
+	tx.do = true
 	return tx.tx.Commit()
 }
 
 func (tx *TX) Rollback() (err error) {
+	tx.do = true
 	return tx.tx.Rollback()
 }
 
diff --git a/kvs/pgsql/tx.go b/kvs/pgsql/tx.go
index 71b00c4e..1f2d48b3 100644
--- a/kvs/pgsql/tx.go
+++ b/kvs/pgsql/tx.go
@@ -28,6 +28,7 @@ import (
 // TX is a distributed database transaction.
 type TX struct {
 	ds *DS
+	do bool
 	ck []byte
 	tx *sql.Tx
 }
@@ -319,6 +320,10 @@ func (tx *TX) RDel(beg, end []byte, max uint64) (err error) {
 
 }
 
+func (tx *TX) Done() (val bool) {
+	return tx.do
+}
+
 func (tx *TX) Close() (err error) {
 	return tx.Rollback()
 }
@@ -328,10 +333,12 @@ func (tx *TX) Cancel() (err error) {
 }
 
 func (tx *TX) Commit() (err error) {
+	tx.do = true
 	return tx.tx.Commit()
 }
 
 func (tx *TX) Rollback() (err error) {
+	tx.do = true
 	return tx.tx.Rollback()
 }
 
diff --git a/kvs/tx.go b/kvs/tx.go
index d003e325..9b37117d 100644
--- a/kvs/tx.go
+++ b/kvs/tx.go
@@ -28,6 +28,7 @@ type TX interface {
 	MDel(...[]byte) error
 	PDel([]byte) error
 	RDel([]byte, []byte, uint64) error
+	Done() bool
 	Close() error
 	Cancel() error
 	Commit() error