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feat(pool): Add Minimum connections, and auto close extra connections #724

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3 changes: 2 additions & 1 deletion lib/connection.js
Original file line number Diff line number Diff line change
Expand Up @@ -103,6 +103,7 @@ function Connection(opts) {
});

this.stream.on('end', function() {
this._closed = true;
// we need to set this flag everywhere where we want connection to close
if (connection._closing) {
return;
Expand Down Expand Up @@ -946,8 +947,8 @@ Connection.prototype.serverHandshake = function serverHandshake(args) {
Connection.prototype.end = function(callback) {
var connection = this;

connection._closing = true;
if (this.config.isServer) {
connection._closing = true;
var quitCmd = new EventEmitter();
setImmediate(function() {
connection.stream.end();
Expand Down
77 changes: 71 additions & 6 deletions lib/pool.js
Original file line number Diff line number Diff line change
@@ -1,6 +1,7 @@
var mysql = require('../index.js');

var EventEmitter = require('events').EventEmitter;
var Timers = require('timers');
var Util = require('util');
var PoolConnection = require('./pool_connection.js');
var Queue = require('denque');
Expand All @@ -18,6 +19,24 @@ function Pool(options) {
this._freeConnections = new Queue();
this._connectionQueue = new Queue();
this._closed = false;
if (this.config.autoOpenConnections && this.config.minConnections) {
var self = this;
var opened = 0;
for (var i = 0; i < this.config.minConnections; i++) {
this.getConnection(function (err, conn) {
if (conn) {
process.nextTick(function () {
if (++opened === self.config.minConnections) {
self._openingConnections = false;
}
self.releaseConnection(conn);
});
}
});
}
// This must be after the getConnection, or else its enqueued
this._openingConnections = true;
}
}

Pool.prototype.getConnection = function(cb) {
Expand All @@ -26,6 +45,10 @@ Pool.prototype.getConnection = function(cb) {
return cb(new Error('Pool is closed.'));
});
}
if (this._openingConnections) {
// We are opening a connect, use it when ready
return this._connectionQueue.push(cb);
}

var connection;

Expand Down Expand Up @@ -82,7 +105,8 @@ Pool.prototype.getConnection = function(cb) {
Pool.prototype.releaseConnection = function(connection) {
var cb;

if (!connection._pool) {
connection._lastReleased = Date.now();
if (!connection._pool || connection._closed || connection._closing) {
// The connection has been removed from the pool and is no longer good.
if (this._connectionQueue.length) {
cb = this._connectionQueue.shift();
Expand All @@ -95,6 +119,7 @@ Pool.prototype.releaseConnection = function(connection) {
process.nextTick(cb.bind(null, null, connection));
} else {
this._freeConnections.push(connection);
this._manageExpiredTimer();
}
};

Expand All @@ -111,14 +136,14 @@ Pool.prototype.end = function(cb) {

var calledBack = false;
var closedConnections = 0;
var connection;
var numConnections = this._allConnections.length;

var endCB = function(err) {
if (calledBack) {
return;
}

if (err || ++closedConnections >= this._allConnections.length) {
if (err || ++closedConnections >= numConnections) {
calledBack = true;
cb(err);
return;
Expand All @@ -130,9 +155,9 @@ Pool.prototype.end = function(cb) {
return;
}

for (var i = 0; i < this._allConnections.length; i++) {
connection = this._allConnections.get(i);
connection._realEnd(endCB);
var connection;
while ((connection = this._allConnections.shift())) {
this._closeConnection(connection, endCB);
}
};

Expand Down Expand Up @@ -184,6 +209,39 @@ Pool.prototype.execute = function(sql, values, cb) {
});
};

Pool.prototype._manageExpiredTimer = function() {
var hasExtra = this._allConnections.length > this.config.minConnections;
if (hasExtra && !this._expiredTimer) {
this._expiredTimer = Timers.setInterval(
Pool.prototype._closeIdleConnections.bind(this),
Math.min(15, this.config.idleTimeout) * 1000
);
} else if (!hasExtra && this._expiredTimer) {
Timers.clearInterval(this._expiredTimer);
this._expiredTimer = null;
}
};

Pool.prototype._closeIdleConnections = function() {
var now = Date.now();
var timeout = this.config.idleTimeout * 1000;
var length = this._freeConnections.length;
var numExtra = this._allConnections.length - this.config.minConnections;
for (var i = 0; numExtra > 0 && i < length; i++) {
var conn = this._freeConnections.get(i);

if (now > conn._lastReleased + timeout) {
// This connection has been unused for longer than the timeout
this._closeConnection(conn);
// decrement i and length as the length will be reduced by 1 by closeConnection
i--;
length--;
numExtra--;
}
}
this._manageExpiredTimer();
};

Pool.prototype._removeConnection = function(connection) {
// Remove connection from all connections
spliceConnection(this._allConnections, connection);
Expand All @@ -192,6 +250,13 @@ Pool.prototype._removeConnection = function(connection) {
spliceConnection(this._freeConnections, connection);

this.releaseConnection(connection);

this._manageExpiredTimer();
};

Pool.prototype._closeConnection = function (connection, cb) {
connection._realEnd(cb);
this._removeConnection(connection);
};

Pool.prototype.format = function(sql, values) {
Expand Down
20 changes: 15 additions & 5 deletions lib/pool_config.js
Original file line number Diff line number Diff line change
Expand Up @@ -6,13 +6,23 @@ function PoolConfig(options) {
options = ConnectionConfig.parseUrl(options);
}
this.connectionConfig = new ConnectionConfig(options);
this.waitForConnections = options.waitForConnections === undefined
this.waitForConnections = options.waitForConnections == null
? true
: Boolean(options.waitForConnections);
this.connectionLimit = options.connectionLimit === undefined
this.connectionLimit = options.connectionLimit == null
? 10
: Number(options.connectionLimit);
this.queueLimit = options.queueLimit === undefined
: Number(options.connectionLimit) || 10;
this.queueLimit = options.queueLimit == null
? 0
: Number(options.queueLimit);
: Number(options.queueLimit) || 0;
this.minConnections = Math.min(
this.connectionLimit,
Number(options.minConnections) || 0
);
this.autoOpenConnections = options.autoOpenConnections == null
? true
: Boolean(options.autoOpenConnections);
this.idleTimeout = options.idleTimeout == null
? 300
: Number(options.idleTimeout) || 300;
}