diff --git a/superset-frontend/src/components/Datasource/DatasourceEditor.jsx b/superset-frontend/src/components/Datasource/DatasourceEditor.jsx
index b695a634aa..326b8e606f 100644
--- a/superset-frontend/src/components/Datasource/DatasourceEditor.jsx
+++ b/superset-frontend/src/components/Datasource/DatasourceEditor.jsx
@@ -762,9 +762,7 @@ class DatasourceEditor extends React.PureComponent {
       database_name:
         datasource.database.database_name || datasource.database.name,
       schema_name: datasource.schema,
-      table_name: datasource.table_name
-        ? encodeURIComponent(datasource.table_name)
-        : datasource.table_name,
+      table_name: datasource.table_name,
       normalize_columns: datasource.normalize_columns,
       always_filter_main_dttm: datasource.always_filter_main_dttm,
     };
@@ -774,7 +772,7 @@ class DatasourceEditor extends React.PureComponent {
         params[key] = null;
       }
     });
-    const endpoint = `/datasource/external_metadata_by_name/?q=${rison.encode(
+    const endpoint = `/datasource/external_metadata_by_name/?q=${rison.encode_uri(
       params,
     )}`;
     this.setState({ metadataLoading: true });
diff --git a/superset-frontend/src/components/Datasource/DatasourceEditor.test.jsx b/superset-frontend/src/components/Datasource/DatasourceEditor.test.jsx
index ae35ebc139..9100eb6c86 100644
--- a/superset-frontend/src/components/Datasource/DatasourceEditor.test.jsx
+++ b/superset-frontend/src/components/Datasource/DatasourceEditor.test.jsx
@@ -75,7 +75,7 @@ describe('DatasourceEditor', () => {
       setTimeout(() => {
         expect(fetchMock.calls(DATASOURCE_ENDPOINT)).toHaveLength(1);
         expect(fetchMock.calls(DATASOURCE_ENDPOINT)[0][0]).toContain(
-          'Vehicle%20Sales%20%2B%27',
+          'Vehicle+Sales%20%2B',
         );
         fetchMock.reset();
         done();