diff --git a/src/database/mongo/hash.js b/src/database/mongo/hash.js
index 78b2e9a61c..a03d14b463 100644
--- a/src/database/mongo/hash.js
+++ b/src/database/mongo/hash.js
@@ -1,5 +1,7 @@
 "use strict";
 
+var winston = require('winston');
+
 module.exports = function(db, module) {
 	var helpers = module.helpers.mongo;
 
@@ -23,6 +25,7 @@ module.exports = function(db, module) {
 	};
 
 	module.getObjects = function(keys, callback) {
+		helpers.checkKeys(keys);
 		db.collection('objects').find({_key: {$in: keys}}, {_id: 0}).toArray(function(err, data) {
 			if(err) {
 				return callback(err);
@@ -53,6 +56,7 @@ module.exports = function(db, module) {
 	};
 
 	module.getObjectsFields = function(keys, fields, callback) {
+		helpers.checkKeys(keys);
 		var _fields = {
 			_id: 0,
 			_key: 1
diff --git a/src/database/mongo/helpers.js b/src/database/mongo/helpers.js
index 689a34bbf0..4a20eed2df 100644
--- a/src/database/mongo/helpers.js
+++ b/src/database/mongo/helpers.js
@@ -1,6 +1,7 @@
 "use strict";
 
-var helpers = {};
+var helpers = {},
+	winston = require('winston');
 
 helpers.toMap = function(data) {
 	var map = {};
@@ -33,4 +34,16 @@ helpers.valueToString = function(value) {
 
 helpers.noop = function() {};
 
+helpers.checkKeys = function(keys) {
+	if (!Array.isArray(keys)) {
+		var e = new Error('invalid keys');
+		winston.warn('[INVALID_KEYS] ',  e.stack);
+		return;
+	}
+	if (keys.length >= 50) {
+		var e = new Error('too many keys');
+		winston.warn('[TOO_MANY_KEYS] ' + keys.length + ' ' + keys[0] + '  ' + keys[keys.length - 1] + '\n', e.stack);
+	}
+}
+
 module.exports = helpers;
\ No newline at end of file