首页 > 代码库 > 从简单的mongodb example 的观察
从简单的mongodb example 的观察
https://github.com/no7dw/mongodb-example
这是最基础的连接查询。（branch master）
var MongoClient = require(‘mongodb‘).MongoClient , assert = require(‘assert‘);// Connection URLvar url = ‘mongodb://localhost:27017/demo‘;var findaddr = function(db, callback) { // Get the addr collection var collection = db.collection(‘addr‘); // Find some addr collection.find({}).toArray(function(err, docs) { callback(err, docs); }); }// Use connect method to connect to the ServerMongoClient.connect(url, function(err, db) { assert.equal(null, err); console.log("Connected correctly to server"); findaddr(db,function(err, docs){ if(err) console.log(‘we get err‘, err); else console.log(‘result:‘, docs); db.close(); }); });
留意到log：
2014-11-20T22:15:52.348+0800 [initandlisten] connection accepted from 127.0.0.1:50076 #39 (1 connection now open)
2014-11-20T22:15:52.384+0800 [conn39] end connection 127.0.0.1:50076 (0 connections now open)
2014-11-20T22:15:52.425+0800 [initandlisten] connection accepted from 127.0.0.1:50077 #40 (1 connection now open)
2014-11-20T22:15:52.426+0800 [initandlisten] connection accepted from 127.0.0.1:50078 #41 (2 connections now open)
2014-11-20T22:15:52.426+0800 [initandlisten] connection accepted from 127.0.0.1:50079 #42 (3 connections now open)
2014-11-20T22:15:52.427+0800 [initandlisten] connection accepted from 127.0.0.1:50080 #43 (4 connections now open)
2014-11-20T22:15:52.428+0800 [initandlisten] connection accepted from 127.0.0.1:50081 #44 (5 connections now open)
2014-11-20T22:15:52.455+0800 [conn40] end connection 127.0.0.1:50077 (4 connections now open)
2014-11-20T22:15:52.455+0800 [conn41] end connection 127.0.0.1:50078 (3 connections now open)
2014-11-20T22:15:52.455+0800 [conn42] end connection 127.0.0.1:50079 (2 connections now open)
2014-11-20T22:15:52.456+0800 [conn43] end connection 127.0.0.1:50080 (1 connection now open)
2014-11-20T22:15:52.456+0800 [conn44] end connection 127.0.0.1:50081 (0 connections now open)
原因：
默认mongodb 使用connection poolsize =5 的设置
所以把他根据业务来设置大小。（branch less-connection）
var options = { db: { native_parser: true }, server: { poolSize: 1 }}// Use connect method to connect to the ServerMongoClient.connect(url, options, function(err, db) { assert.equal(null, err); console.log("Connected correctly to server"); findaddr(db,function(err, docs){ if(err) console.log(‘we get err‘, err); else console.log(‘result:‘, docs); db.close(); }); });
now see mongd log:
2014-11-20T22:21:46.243+0800 [initandlisten] connection accepted from 127.0.0.1:50157 #45 (1 connection now open)2014-11-20T22:21:46.255+0800 [conn45] end connection 127.0.0.1:50157 (0 connections now open)2014-11-20T22:21:46.266+0800 [initandlisten] connection accepted from 127.0.0.1:50158 #46 (1 connection now open)2014-11-20T22:21:46.278+0800 [conn46] end connection 127.0.0.1:50158 (0 connections now open)
seems good. However, 这样设置不能根据业务压力来调整，even 有 maxPoolSize, minPoolSize :
- uri.maxPoolSize¶
The maximum number of connections in the connection pool. The default value is 100.
- uri.minPoolSize
The minimum number of connections in the connection pool. The default value is 0.
--- 答案是：
generic-pool
从简单的mongodb example 的观察