MongoDB 驱动以及分布式集群读取优先级设置

    mongoc_read_prefs_t* read_prefs = mongoc_read_prefs_new(MONGOC_READ_NEAREST);
    bson_t* tag = bson_new();
    mongoc_read_prefs_add_tag(read_prefs, tag);
    bson_destroy(tag);  
    mongoc_cursor_t* cursor = mongoc_collection_find(collection, MONGOC_QUERY_NONE, 0, 1, 0, query, NULL, read_prefs); 

#!/home/work/bin/python
# test find  with tag_set
# cswuyg @ 2014.7.18
# install pymongo pre.

import pymongo
import time

REMOTE_ADDRESS = "xxxxhost"
REMOTE_PORT = 27030
def _test_find():
    f_w = open("test", ‘w‘)
    #client = pymongo.MongoClient(REMOTE_ADDRESS, 27030, readPreference=‘nearest‘)
    rpre = pymongo.read_preferences.Secondary(tag_sets = [{‘location‘: ‘gz‘}])
    client = pymongo.MongoClient(REMOTE_ADDRESS, REMOTE_PORT, read_preference=rpre) # 注意这里的read_preference
    s = time.time()
    docs = client.myapp.myuser.find({‘name‘: ‘cswuyg‘})
    with open(‘tmp.txt‘, ‘w‘) as f_w: 
        for item in docs:
            f_w.write(str(item))
            f_w.write(‘\n‘)

    e = time.time()
    print(e - s)

if __name__ == "__main__":
    _test_find()

/*
* 测试 mongodb 驱动 耗时
* cswuyg @ 2015.12.29
*/
"use strict";
var mongodb = require(‘mongodb‘);
var assert = require(‘assert‘);
var fs = require(‘fs‘);
var url = ‘mongodb://xxxhost:27030/myapp?w=1&readPreference=nearest&readPreferenceTags=location:bj‘;   //在uri上设置读取优先级和tag

var findDocuments = function(collection, callback) {
    collection.find({‘name‘: ‘cswuyg‘}).limit(1).toArray(function(err, docs) {
        callback(docs);
    });      
}

mongodb.MongoClient.connect(url, function(err, db) {
    assert.equal(null, err);
    console.log("Connected correctly to server");
    var col = db.collection(‘myuser‘);
    var s = new Date().getTime();
    findDocuments(col, function(docs) {
        var writerStream = fs.createWriteStream(‘tmp.txt‘);
        writerStream.write(JSON.stringify(docs[0]), ‘UTF8‘);
        writerStream.end();
        var e = new Date().getTime();
        console.log(e - s);
    });
});

/*
* * 测试 mongoose 耗时
* * cswuyg @ 2015.12.29
* */
"use strict";

var mongoose = require(‘mongoose‘);
var fs = require(‘fs‘);
var connect = mongoose.createConnection(‘mongodb://xxxhost:27030, yyyhost:27030/myapp‘, {mongos: true});   //注意mongos

var schema = {name: {type: String}};
var colSchema = new mongoose.Schema(schema, {collection: ‘myuser‘});
var model = connect.model(‘myuser‘, colSchema);

setTimeout(function() {
    var s = new Date().getTime();
    var query = new mongoose.Query({‘name‘: ‘cswuyg‘}).read(‘n‘, [{location:‘nj‘}]);  //Query层面设置读取优先级和tag
    model.find(query).exec(function(err, doc) {
        var writerStream = fs.createWriteStream(‘output.txt‘);
        writerStream.write(doc.toString(), ‘UTF8‘);
        writerStream.end();
        var e = new Date().getTime();
        console.log(e - s);
    });

}, 1000);

setTimeout(function() {
    var s = new Date().getTime();
    var query = new mongoose.Query({‘name‘: ‘cswuyg‘}).read(‘n‘, [{location:‘nj‘}]);
    model.find(query).exec(function(err, doc) {
        var writerStream = fs.createWriteStream(‘output.txt‘);
        writerStream.write(doc.toString(), ‘UTF8‘);
        writerStream.end();
        var e = new Date().getTime();
        console.log(e - s);
    });

}, 2000);