New Pool options and refactoring.

Readme.md

@@ -389,12 +389,27 @@ constructor. In addition to those options pools accept a few extras:
 * `queueLimit`: The maximum number of connection requests the pool will queue
   before returning an error from `getConnection`. If set to `0`, there is no
   limit to the number of queued connection requests. (Default: `0`)
+* `queueWaitTimeout`: The maximum number of milliseconds that the pool will wait
+  for a connection when there are no available spare connections. If set to `0`,
+  there is no limit. (Default: `0`)
+* `pingCheckInterval`: The number of milliseconds to indicate how often to check
+  the validity of the connection. If set to `0`, checks whether or not the connection
+  to the server is working every time. Setting this value in high-traffic can
+  improve performance. (Default: `0`)
+* `startConnections`: The initial number of connections that are created when the
+  pool is started. (Default: `0`)
+* `minSpareConnections`: The minimum number of spare connections that should be
+  kept in the pool at all times. If set to `0`, it doen't work. (Default: `0`)
+* `maxSpareConnections`: The maximum number of spare connections that should be
+  kept in the pool at all times. If set to `0`, it doen't work. (Default: `0`)
+* `spareCheckInterval`: The number of milliseconds to indicate how often to check
+  the status of spare connections. If set to `0`, it doen't work. (Default: `0`)
 
 ## Pool events
 
 ### connection
 
-The pool will emit a `connection` event when a new connection is made within the pool. 
+The pool will emit a `connection` event when a new connection is made within the pool.
 If you need to set session variables on the connection before it gets used, you can
 listen to the `connection` event.
 
@@ -415,6 +430,11 @@ pool.on('enqueue', function () {
 });
 ```
 
+### prepared
+
+The pool will emit an `prepared` event when all new connections are created in.
+It's meaningful when `startConnections` is set.
+
 ## Closing all the connections in a pool
 
 When you are done using the pool, you have to end all the connections or the
@@ -463,7 +483,7 @@ poolCluster.getConnection('MASTER', function (err, connection) {});
 // Target Group : SLAVE1-2, Selector : order
 // If can't connect to SLAVE1, return SLAVE2. (remove SLAVE1 in the cluster)
 poolCluster.on('remove', function (nodeId) {
-  console.log('REMOVED NODE : ' + nodeId); // nodeId = SLAVE1 
+  console.log('REMOVED NODE : ' + nodeId); // nodeId = SLAVE1
 });
 
 poolCluster.getConnection('SLAVE*', 'ORDER', function (err, connection) {});
@@ -485,7 +505,7 @@ poolCluster.end(function (err) {
 ### PoolCluster options
 
 * `canRetry`: If `true`, `PoolCluster` will attempt to reconnect when connection fails. (Default: `true`)
-* `removeNodeErrorCount`: If connection fails, node's `errorCount` increases. 
+* `removeNodeErrorCount`: If connection fails, node's `errorCount` increases.
   When `errorCount` is greater than `removeNodeErrorCount`, remove a node in the `PoolCluster`. (Default: `5`)
 * `restoreNodeTimeout`: If connection fails, specifies the number of milliseconds
   before another connection attempt will be made. If set to `0`, then node will be

lib/ConnectionConfig.js

@@ -56,10 +56,22 @@ function ConnectionConfig(options) {
     : options.charsetNumber||Charsets.UTF8_GENERAL_CI;
 
   // Set the client flags
-  var defaultFlags = ConnectionConfig.getDefaultFlags(options);
-  this.clientFlags = ConnectionConfig.mergeFlags(defaultFlags, options.flags);
+  this.clientFlags = ConnectionConfig._getClientFlags(this.multipleStatements, this.flags);
 }
 
+var _clientFlagsCache = {};
+
+ConnectionConfig._getClientFlags = function(multipleStatements, flags) {
+  var key = flags + multipleStatements;
+
+  if (_clientFlagsCache[key] === undefined) {
+    var defaultFlags = ConnectionConfig.getDefaultFlags(multipleStatements);
+    _clientFlagsCache[key] = ConnectionConfig.mergeFlags(defaultFlags, flags);
+  }
+
+  return _clientFlagsCache[key];
+};
+
 ConnectionConfig.mergeFlags = function mergeFlags(defaultFlags, userFlags) {
   var allFlags = ConnectionConfig.parseFlagList(defaultFlags);
   var newFlags = ConnectionConfig.parseFlagList(userFlags);
@@ -93,7 +105,7 @@ ConnectionConfig.getCharsetNumber = function getCharsetNumber(charset) {
   return num;
 };
 
-ConnectionConfig.getDefaultFlags = function getDefaultFlags(options) {
+ConnectionConfig.getDefaultFlags = function getDefaultFlags(multipleStatements) {
   var defaultFlags = [
     '-COMPRESS',          // Compression protocol *NOT* supported
     '-CONNECT_ATTRS',     // Does *NOT* send connection attributes in Protocol::HandshakeResponse41
@@ -114,7 +126,7 @@ ConnectionConfig.getDefaultFlags = function getDefaultFlags(options) {
     '+TRANSACTIONS'       // Expects status flags
   ];
 
-  if (options && options.multipleStatements) {
+  if (multipleStatements) {
     // May send multiple statements per COM_QUERY and COM_STMT_PREPARE
     defaultFlags.push('+MULTI_STATEMENTS');
   }