diff --git a/common/seaf-db.c b/common/seaf-db.c
index 343931e6..4093b444 100644
--- a/common/seaf-db.c
+++ b/common/seaf-db.c
@@ -845,6 +845,14 @@ mysql_db_get_connection (SeafDB *vdb)
     if (db->charset)
         mysql_options(db_conn, MYSQL_SET_CHARSET_NAME, db->charset);
 
+    if (db->unix_socket) {
+        int pro_type = MYSQL_PROTOCOL_SOCKET;
+        mysql_options (db_conn, MYSQL_OPT_PROTOCOL, &pro_type);
+        if (!db->user) {
+           mysql_options (db_conn, MYSQL_DEFAULT_AUTH, "unix_socket");
+        }
+    }
+
     mysql_options(db_conn, MYSQL_OPT_CONNECT_TIMEOUT, (const char*)&conn_timeout);
     mysql_options(db_conn, MYSQL_OPT_READ_TIMEOUT, (const char*)&read_write_timeout);
     mysql_options(db_conn, MYSQL_OPT_WRITE_TIMEOUT, (const char*)&read_write_timeout);
diff --git a/common/seaf-utils.c b/common/seaf-utils.c
index a2bfc76b..e8db8ee5 100644
--- a/common/seaf-utils.c
+++ b/common/seaf-utils.c
@@ -67,8 +67,11 @@ mysql_db_start (SeafileSession *session)
     int max_connections = 0;
     GError *error = NULL;
 
+    unix_socket = seaf_key_file_get_string (session->config, 
+                                         "database", "unix_socket", NULL);
+
     host = seaf_key_file_get_string (session->config, "database", "host", &error);
-    if (!host) {
+    if (!host && !unix_socket) {
         seaf_warning ("DB host not set in config.\n");
         return -1;
     }
@@ -79,13 +82,13 @@ mysql_db_start (SeafileSession *session)
     }
 
     user = seaf_key_file_get_string (session->config, "database", "user", &error);
-    if (!user) {
+    if (!user && !unix_socket) {
         seaf_warning ("DB user not set in config.\n");
         return -1;
     }
 
     passwd = seaf_key_file_get_string (session->config, "database", "password", &error);
-    if (!passwd) {
+    if (!passwd && !unix_socket) {
         seaf_warning ("DB passwd not set in config.\n");
         return -1;
     }
@@ -96,9 +99,6 @@ mysql_db_start (SeafileSession *session)
         return -1;
     }
 
-    unix_socket = seaf_key_file_get_string (session->config, 
-                                         "database", "unix_socket", NULL);
-
     use_ssl = g_key_file_get_boolean (session->config,
                                       "database", "use_ssl", NULL);
 
@@ -274,16 +274,18 @@ ccnet_init_mysql_database (SeafileSession *session)
     user = ccnet_key_file_get_string (session->ccnet_config, "Database", "USER");
     passwd = ccnet_key_file_get_string (session->ccnet_config, "Database", "PASSWD");
     db = ccnet_key_file_get_string (session->ccnet_config, "Database", "DB");
+    unix_socket = ccnet_key_file_get_string (session->ccnet_config,
+                                             "Database", "UNIX_SOCKET");
 
-    if (!host) {
+    if (!host && !unix_socket) {
         seaf_warning ("DB host not set in config.\n");
         return -1;
     }
-    if (!user) {
+    if (!user && !unix_socket) {
         seaf_warning ("DB user not set in config.\n");
         return -1;
     }
-    if (!passwd) {
+    if (!passwd && !unix_socket) {
         seaf_warning ("DB passwd not set in config.\n");
         return -1;
     }
@@ -299,8 +301,6 @@ ccnet_init_mysql_database (SeafileSession *session)
         port = MYSQL_DEFAULT_PORT;
     }
 
-    unix_socket = ccnet_key_file_get_string (session->ccnet_config,
-                                             "Database", "UNIX_SOCKET");
     use_ssl = g_key_file_get_boolean (session->ccnet_config, "Database", "USE_SSL", NULL);
     skip_verify = g_key_file_get_boolean (session->ccnet_config, "Database", "SKIP_VERIFY", NULL);
     if (use_ssl && !skip_verify) {
diff --git a/fileserver/fileserver.go b/fileserver/fileserver.go
index 43066f12..9b84ec90 100644
--- a/fileserver/fileserver.go
+++ b/fileserver/fileserver.go
@@ -91,18 +91,27 @@ func loadCcnetDB() {
 	}
 
 	if strings.EqualFold(dbEngine, "mysql") {
-		if key, err = section.GetKey("HOST"); err != nil {
+		unixSocket := ""
+		if key, err = section.GetKey("UNIX_SOCKET"); err == nil {
+			unixSocket = key.String()
+		}
+		host := ""
+		if key, err = section.GetKey("HOST"); err == nil {
+			host = key.String()
+		} else if unixSocket == "" {
 			log.Fatal("No database host in ccnet.conf.")
 		}
-		host := key.String()
+		// user is required.
 		if key, err = section.GetKey("USER"); err != nil {
 			log.Fatal("No database user in ccnet.conf.")
 		}
 		user := key.String()
-		if key, err = section.GetKey("PASSWD"); err != nil {
+		password := ""
+		if key, err = section.GetKey("PASSWD"); err == nil {
+			password = key.String()
+		} else if unixSocket == "" {
 			log.Fatal("No database password in ccnet.conf.")
 		}
-		password := key.String()
 		if key, err = section.GetKey("DB"); err != nil {
 			log.Fatal("No database db_name in ccnet.conf.")
 		}
@@ -111,10 +120,6 @@ func loadCcnetDB() {
 		if key, err = section.GetKey("PORT"); err == nil {
 			port, _ = key.Int()
 		}
-		unixSocket := ""
-		if key, err = section.GetKey("UNIX_SOCKET"); err == nil {
-			unixSocket = key.String()
-		}
 		useTLS := false
 		if key, err = section.GetKey("USE_SSL"); err == nil {
 			useTLS, _ = key.Bool()
@@ -191,18 +196,28 @@ func loadSeafileDB() {
 		dbEngine = key.String()
 	}
 	if strings.EqualFold(dbEngine, "mysql") {
-		if key, err = section.GetKey("host"); err != nil {
+		unixSocket := ""
+		if key, err = section.GetKey("unix_socket"); err == nil {
+			unixSocket = key.String()
+		}
+		host := ""
+		if key, err = section.GetKey("host"); err == nil {
+			host = key.String()
+		} else if unixSocket == "" {
 			log.Fatal("No database host in seafile.conf.")
 		}
-		host := key.String()
+		// user is required.
 		if key, err = section.GetKey("user"); err != nil {
 			log.Fatal("No database user in seafile.conf.")
 		}
 		user := key.String()
-		if key, err = section.GetKey("password"); err != nil {
+
+		password := ""
+		if key, err = section.GetKey("password"); err == nil {
+			password = key.String()
+		} else if unixSocket == "" {
 			log.Fatal("No database password in seafile.conf.")
 		}
-		password := key.String()
 		if key, err = section.GetKey("db_name"); err != nil {
 			log.Fatal("No database db_name in seafile.conf.")
 		}
@@ -211,10 +226,6 @@ func loadSeafileDB() {
 		if key, err = section.GetKey("port"); err == nil {
 			port, _ = key.Int()
 		}
-		unixSocket := ""
-		if key, err = section.GetKey("unix_socket"); err == nil {
-			unixSocket = key.String()
-		}
 		useTLS := false
 		if key, err = section.GetKey("use_ssl"); err == nil {
 			useTLS, _ = key.Bool()
diff --git a/notification-server/server.go b/notification-server/server.go
index 6d59e72d..de938b40 100644
--- a/notification-server/server.go
+++ b/notification-server/server.go
@@ -104,18 +104,28 @@ func loadCcnetDB() {
 		log.Fatalf("Unsupported database %s.", dbEngine)
 	}
 
-	if key, err = section.GetKey("HOST"); err != nil {
+	unixSocket := ""
+	if key, err = section.GetKey("UNIX_SOCKET"); err == nil {
+		unixSocket = key.String()
+	}
+
+	host := ""
+	if key, err = section.GetKey("HOST"); err == nil {
+		host = key.String()
+	} else if unixSocket == "" {
 		log.Fatal("No database host in ccnet.conf.")
 	}
-	host := key.String()
+	// user is required.
 	if key, err = section.GetKey("USER"); err != nil {
 		log.Fatal("No database user in ccnet.conf.")
 	}
 	user := key.String()
-	if key, err = section.GetKey("PASSWD"); err != nil {
+	password := ""
+	if key, err = section.GetKey("PASSWD"); err == nil {
+		password = key.String()
+	} else if unixSocket == "" {
 		log.Fatal("No database password in ccnet.conf.")
 	}
-	password := key.String()
 	if key, err = section.GetKey("DB"); err != nil {
 		log.Fatal("No database db_name in ccnet.conf.")
 	}
@@ -124,10 +134,6 @@ func loadCcnetDB() {
 	if key, err = section.GetKey("PORT"); err == nil {
 		port, _ = key.Int()
 	}
-	unixSocket := ""
-	if key, err = section.GetKey("UNIX_SOCKET"); err == nil {
-		unixSocket = key.String()
-	}
 	useTLS := false
 	if key, err = section.GetKey("USE_SSL"); err == nil {
 		useTLS, _ = key.Bool()