From 8d691b20481104fb2beea5c00d59b2ec63293b4d Mon Sep 17 00:00:00 2001
From: Javier Goizueta <jgoizueta@gmail.com>
Date: Fri, 22 Jan 2016 11:03:01 +0100
Subject: [PATCH] Refactor OverviewsApi

Separate metadata processing into collecting each layer's information (map)
and then organizing metadata per tables/zoom levels (reduce).
---
 lib/cartodb/api/overviews_api.js | 27 +++++++++++++++------------
 1 file changed, 15 insertions(+), 12 deletions(-)

diff --git a/lib/cartodb/api/overviews_api.js b/lib/cartodb/api/overviews_api.js
index 81d279b1..2a677210 100644
--- a/lib/cartodb/api/overviews_api.js
+++ b/lib/cartodb/api/overviews_api.js
@@ -19,8 +19,6 @@ OverviewsApi.prototype.getOverviewsMetadata = function (username, sql, callback)
         if (err) {
             callback(err);
         } else {
-            var metadata = {};
-
             var parallelism = 2;
             var q = queue(parallelism);
 
@@ -33,23 +31,28 @@ OverviewsApi.prototype.getOverviewsMetadata = function (username, sql, callback)
                             done(new Error('could not get overviews metadata: ' + msg));
                             return;
                         }
-                        if ( rows.length > 0 ) {
-                          var table_metadata = {};
-                          for ( var i=0; i<rows.length; ++i ) {
-                            var row = rows[i];
-                            table_metadata[row.z] = { table: row.overview_table };
-                          }
-                          metadata[tableName] = table_metadata;
-                        }
-                        done(null);
+                        done(null, [tableName, rows]);
                     });
                 });
             });
 
-            q.awaitAll(function(err){
+            var metadata = {};
+            q.awaitAll(function(err, results){
               if (err) {
                   return callback(err);
               } else {
+                  results.forEach(function(table_rows) {
+                      var tableName = table_rows[0];
+                      var rows = table_rows[1];
+                      if ( rows.length > 0 ) {
+                          var table_metadata = {};
+                          for ( var i=0; i<rows.length; ++i ) {
+                              var row = rows[i];
+                              table_metadata[row.z] = { table: row.overview_table };
+                          }
+                          metadata[tableName] = table_metadata;
+                      }
+                  });
                   return callback(null, metadata);
               }
             });