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使用php mongodb扩展时需要注意的地方

PHP #mongodb #扩展2012-09-13 11:18
MongoDB是一个基于分布式文件存储的数据库。由C++语言编写。旨在为WEB应用提供可扩展的高性能数据存储解决方案。

MongoDB是一个介于关系数据库和非关系数据库之间的产品。Mongo最大的特点是他支持的查询语言非常强大，其语法有点类似于面向对象的查询语言，几乎可以实现类似关系数据库单表查询的绝大部分功能，而且还支持对数据建立索引。

最近在使用php的mongo 扩展进行数据统计计算，其中有一个时间戳字段，由于精确到了毫秒，长度有13位，但由于开始的时候是以字符串的形式存储：

{ "_id" : ObjectId("504eea97e4b023cf38e34039"), "in_ts" : NumberLong("1347349143699"), "log" : { "guid" : "4D1F3079-7507-F4B0-E7AF-5432D5D8229D", "p" : "View_Prop_YepPage_Zheng", "cid" : "11", "url" : "http://shanghai.yige.org/rental/broker/n/10481780", "rfpn" : "Listing_V2_IndexPage_All", "site" : "yige", "agent" : "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1)", "stamp" : "1347349162159", "cip" : "116.226.70.44", "referer" : "http://shanghai.yige.org/shop/1464934/", "cstamp" : "1347349323125", "sessid" : "FA798056-F9E7-F961-41E0-CC95C850FA47", "uguid" : "C00FF55B-3D3D-4B31-4318-12345B0DBE64", "pn" : "View_Prop_YepPage_Zheng", "cstparam" : { "proId" : NumberLong(10481780), "brokerId" : "326792", "tradeType" : "2", "userType" : "0", "channel" : "site", "entry" : "1", "COMMID" : "1666" } }, "out_ts" : NumberLong("1347349466083"), "rule" : 0, "status" : "ok", "txid" : 0 }

后来改成数字格式：

{ "_id" : ObjectId("504eea97e4b023cf38e34039"), "in_ts" : NumberLong("1347349143699"), "log" : { "guid" : "4D1F3079-7507-F4B0-E7AF-5432D5D8229D", "p" : "View_Prop_YepPage_Zheng", "cid" : "11", "url" : "http://shanghai.yige.org/rental/broker/n/10481780", "rfpn" : "Listing_V2_IndexPage_All", "site" : "yige", "agent" : "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1)", "stamp" : NumberLong("1347349162159"), "cip" : "116.226.70.44", "referer" : "http://shanghai.yige.org/shop/1464934/", "cstamp" : "1347349323125", "sessid" : "FA798056-F9E7-F961-41E0-CC95C850FA47", "uguid" : "C00FF55B-3D3D-4B31-4318-12345B0DBE64", "pn" : "View_Prop_YepPage_Zheng", "cstparam" : { "proId" : NumberLong(10481780), "brokerId" : "326792", "tradeType" : "2", "userType" : "0", "channel" : "site", "entry" : "1", "COMMID" : "1666" } }, "out_ts" : NumberLong("1347349466083"), "rule" : 0, "status" : "ok", "txid" : 0 }


为字符串时，使用下面的查询是正常的

 $query = array ('log.stamp' => array ('$gte' => ‘1347346800000’, '$lt' => ‘1347350400000’));

但是改为数字后，使用下面的查询，死活没有结果，但是直接在mongo客户端直接查询是有结果的：
 

 db.yige_success.find({'log.stamp':{$gte:1347346800000,$lt:1347350400000}})

php手册上也是这么个用法：

 $query = array ('log.stamp' => array ('$gte' => 1347346800000, '$lt' => 1347350400000));

花了好大一会找原因，开始时怀疑是php扩展的bug导致，经过一番思考。突然想到可能是类型问题导致，发现手册上有Types 介绍，所以正确的用法如下：

$query = array ('log.stamp' => array ('$gte' => new MongoInt64($time_range['start']), '$lt' => new MongoInt64($time_range['end'])));
 
另外，在使用mapreduce进行数据统计时，为了防止cursor出现超时异常，还需要设置一下超时时间
$map = new MongoCode ( '
                function(){
                    var prop_id=this.log.cstparam.proId;
                    var key=this.log.site+prop_id
                    emit(key,{"channel":this.log.site,"prop_id":prop_id,"count":1});
                }
                ' );
        $reduce = new MongoCode ( '
                function(key,emits){
                    var total=0;
                    for(var i in emits){
                        total+=emits[i].count;
                    }
                    return {"channel":emits[0].channel,"prop_id":eval(emits[0].prop_id),"count":total};
                }
                ' );
$this->mongo_db->command ( array ('mapreduce' => $collection_name, 'map' => $map, 'reduce' => $reduce, 'out' => $tmp_result, 'query' => $query),array('timeout'=>self::MONGO_CURSOR_TIMEOUT) );

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