diff --git a/lib/cartodb/api/overviews_metadata_api.js b/lib/cartodb/api/overviews_metadata_api.js
index b052c732..af3a1294 100644
--- a/lib/cartodb/api/overviews_metadata_api.js
+++ b/lib/cartodb/api/overviews_metadata_api.js
@@ -34,12 +34,11 @@ OverviewsMetadataApi.prototype.getOverviewsMetadata = function (username, sql, c
         var metadata = rows.reduce(function(metadata, row){
             var table = row.base_table;
             var schema = row._cdb_schema_name;
-            var table_metadata = metadata[table];
-            if ( !table_metadata ) {
-                table_metadata = metadata[table] = {};
+            if ( !metadata[table] ) {
+                metadata[table] = {};
             }
-            table_metadata[row.z] = { table: row.overview_table };
-            table_metadata.schema = schema;
+            metadata[table][row.z] = { table: row.overview_table };
+            metadata[table].schema = schema;
             return metadata;
         }, {});
         return callback(null, metadata);