Merge pull request #3285 from mbroadst/mssql-disconnect-issue

fix tedious error handling

lib/dialects/mssql/connection-manager.js

@@ -47,11 +47,6 @@ ConnectionManager.prototype.connect = function(config) {
     var connection = new self.lib.Connection(connectionConfig);
     connection.lib = self.lib;
 
-    // don't let tedious errors take down the entire application
-    connection.on('error', function(err) {
-      connection._invalid = true;
-    });
-
     connection.on('connect', function(err) {
       if (!err) {
         resolve(connection);
@@ -93,12 +88,23 @@ ConnectionManager.prototype.connect = function(config) {
         break;
       }
     });
+
+    if (config.pool.handleDisconnects) {
+      connection.on('error', function (err) {
+        switch (err.code) {
+        case 'ESOCKET':
+        case 'ECONNRESET':
+          self.pool.destroy(connection);
+        }
+      });
+    }
+
   });
 };
 
 ConnectionManager.prototype.disconnect = function(connection) {
   // Dont disconnect a connection that is already disconnected
-  if (!connection.connected) {
+  if (!!connection.closed) {
     return Promise.resolve();
   }