diff --git a/lib/cartodb/api/auth_api.js b/lib/cartodb/api/auth_api.js
index bacccda7..8782f907 100644
--- a/lib/cartodb/api/auth_api.js
+++ b/lib/cartodb/api/auth_api.js
@@ -70,7 +70,7 @@ AuthApi.prototype.authorizedByAPIKey = function(user, res, callback) {
 
     this.metadataBackend.getApikey(user, apikeyToken, (err, apikey) => {
         if (err) {
-            if (err.message && -1 !== err.message.indexOf('name not found')) {
+            if (isNameNotFoundError(err)) {
                 err.http_status = 404;
             }
 
@@ -79,15 +79,8 @@ AuthApi.prototype.authorizedByAPIKey = function(user, res, callback) {
 
         //Remove this block when Auth fallback is not used anymore
         // AUTH_FALLBACK
-        if (!apikey.databaseRole && apikey.user_id && global.environment.postgres_auth_user) {
-            apikey.databaseRole = _.template(global.environment.postgres_auth_user, apikey);
-        }
-
-        //Remove this block when Auth fallback is not used anymore
-        // AUTH_FALLBACK
-        if (!apikey.databasePassword && global.environment.postgres.password) {
-            apikey.databasePassword = global.environment.postgres.password;
-        }
+        apikey.databaseRole = composeUserDatabase(apikey);
+        apikey.databasePassword = composeDatabasePassword(apikey);
 
         if ( !isValidApiKey(apikey)) {
             const error = new Error('Unauthorized');
@@ -98,7 +91,7 @@ AuthApi.prototype.authorizedByAPIKey = function(user, res, callback) {
             return callback(error);
         }
 
-        if (apikeyUsername && (apikeyUsername !== res.locals.user)) {
+        if (!usernameMatches(apikeyUsername, res.locals.user)) {
             const error = new Error('Forbidden');
             error.type = 'auth';
             error.subtype = 'api-key-username-mismatch';
@@ -120,6 +113,46 @@ AuthApi.prototype.authorizedByAPIKey = function(user, res, callback) {
     });
 };
 
+//Remove this block when Auth fallback is not used anymore
+// AUTH_FALLBACK
+function composeUserDatabase (apikey) {
+    if (shouldComposeUserDatabase(apikey)) {
+        return _.template(global.environment.postgres_auth_user, apikey);
+    }
+
+    return apikey.databaseRole;
+}
+
+//Remove this block when Auth fallback is not used anymore
+// AUTH_FALLBACK
+function composeDatabasePassword (apikey) {
+    if (shouldComposeDatabasePassword(apikey)) {
+        return global.environment.postgres.password;
+    }
+
+    return apikey.databasePassword;
+}
+
+//Remove this block when Auth fallback is not used anymore
+// AUTH_FALLBACK
+function shouldComposeDatabasePassword (apikey) {
+    return !apikey.databasePassword && global.environment.postgres.password;
+}
+
+//Remove this block when Auth fallback is not used anymore
+// AUTH_FALLBACK
+function shouldComposeUserDatabase(apikey) {
+    return !apikey.databaseRole && apikey.user_id && global.environment.postgres_auth_user;
+}
+
+function isNameNotFoundError (err) {
+    return err.message && -1 !== err.message.indexOf('name not found');
+}
+
+function usernameMatches (apikeyUsername, requestUsername) {
+    return !(apikeyUsername && (apikeyUsername !== requestUsername));
+}
+
 /**
  * Check access authorization
  *
diff --git a/lib/cartodb/backends/pg_connection.js b/lib/cartodb/backends/pg_connection.js
index 71ec2928..290fb6ef 100644
--- a/lib/cartodb/backends/pg_connection.js
+++ b/lib/cartodb/backends/pg_connection.js
@@ -22,7 +22,7 @@ PgConnection.prototype.setDBAuth = function(username, params, apikeyType, callba
     if (apikeyType === 'master') {
         this.metadataBackend.getMasterApikey(username, (err, apikey) => {
             if (err) {
-                if (err.message && -1 !== err.message.indexOf('name not found')) {
+                if (isNameNotFoundError(err)) {
                     err.http_status = 404;
                 }
                 return callback(err);
@@ -42,7 +42,7 @@ PgConnection.prototype.setDBAuth = function(username, params, apikeyType, callba
     } else if (apikeyType === 'regular') { //Actually it can be any type of api key
         this.metadataBackend.getApikey(username, params.api_key, (err, apikey) => {
             if (err) {
-                if (err.message && -1 !== err.message.indexOf('name not found')) {
+                if (isNameNotFoundError(err)) {
                     err.http_status = 404;
                 }
                 return callback(err);
@@ -75,7 +75,7 @@ PgConnection.prototype.setDBAuth = function(username, params, apikeyType, callba
     } else if (apikeyType === 'default') {
         this.metadataBackend.getApikey(username, 'default_public', (err, apikey) => {
             if (err) {
-                if (err.message && -1 !== err.message.indexOf('name not found')) {
+                if (isNameNotFoundError(err)) {
                     err.http_status = 404;
                 }
                 return callback(err);
@@ -97,6 +97,11 @@ PgConnection.prototype.setDBAuth = function(username, params, apikeyType, callba
     }
 };
 
+function isNameNotFoundError (err) {
+    return err.message && -1 !== err.message.indexOf('name not found');
+}
+
+
 // Set db connection parameters to those for the given username
 //
 // @param dbowner cartodb username of database owner,