php结合redis实现秒杀功能

<?php

第一种，简单实现

$conn=mysql_connect("localhost","big","123456");

if(!$conn){

    echo "connect failed";

    exit;

}

mysql_select_db("big",$conn);

mysql_query("set names utf8");

 

$price=10;

$user_id=1;

$goods_id=1;

$sku_id=11;

$number=1;

 

//生成唯一订单

function build_order_no(){

  return date('ymd').substr(implode(NULL, array_map('ord', str_split(substr(uniqid(), 7, 13), 1))), 0, 8);

}

//记录日志

function insertLog($event,$type=0){

    global $conn;

    $sql="insert into ih_log(event,type)

    values('$event','$type')";

    mysql_query($sql,$conn);

}

 

//模拟下单操作

//库存是否大于0

$sql="select number from ih_store where goods_id='$goods_id' and sku_id='$sku_id'";//解锁 此时ih_store数据中goods_id='$goods_id' and sku_id='$sku_id' 的数据被锁住(注3)，其它事务必须等待此次事务 提交后才能执行

$rs=mysql_query($sql,$conn);

$row=mysql_fetch_assoc($rs);

if($row['number']>0){//高并发下会导致超卖

    $order_sn=build_order_no();

    //生成订单

    $sql="insert into ih_order(order_sn,user_id,goods_id,sku_id,price)

    values('$order_sn','$user_id','$goods_id','$sku_id','$price')";

    $order_rs=mysql_query($sql,$conn);

     

    //库存减少

    $sql="update ih_store set number=number-{$number} where sku_id='$sku_id'";

    $store_rs=mysql_query($sql,$conn);

    if(mysql_affected_rows()){

        insertLog('库存减少成功');

    }else{

        insertLog('库存减少失败');

    }

}else{

    insertLog('库存不够');

}

?>.

第二种，使用mysql锁行的方式

 

<?php

$conn=mysql_connect("localhost","big","123456");

if(!$conn){

    echo "connect failed";

    exit;

}

mysql_select_db("big",$conn);

mysql_query("set names utf8");

 

$price=10;

$user_id=1;

$goods_id=1;

$sku_id=11;

$number=1;

 

//生成唯一订单号

function build_order_no(){

  return date('ymd').substr(implode(NULL, array_map('ord', str_split(substr(uniqid(), 7, 13), 1))), 0, 8);

}

//记录日志

function insertLog($event,$type=0){

    global $conn;

    $sql="insert into ih_log(event,type)

    values('$event','$type')";

    mysql_query($sql,$conn);

}

 

//模拟下单操作

//库存是否大于0

mysql_query("BEGIN");   //开始事务

$sql="select number from ih_store where goods_id='$goods_id' and sku_id='$sku_id' FOR UPDATE";//此时这条记录被锁住,其它事务必须等待此次事务提交后才能执行

$rs=mysql_query($sql,$conn);

$row=mysql_fetch_assoc($rs);

if($row['number']>0){

    //生成订单

    $order_sn=build_order_no();

    $sql="insert into ih_order(order_sn,user_id,goods_id,sku_id,price)

    values('$order_sn','$user_id','$goods_id','$sku_id','$price')";

    $order_rs=mysql_query($sql,$conn);

     

    //库存减少

    $sql="update ih_store set number=number-{$number} where sku_id='$sku_id'";

    $store_rs=mysql_query($sql,$conn);

    if(mysql_affected_rows()){

        insertLog('库存减少成功');

        mysql_query("COMMIT");//事务提交即解锁

    }else{

        insertLog('库存减少失败');

    }

}else{

    insertLog('库存不够');

    mysql_query("ROLLBACK");

}

?>

 

第三种，使用非阻塞的文件排他锁

 

<?php
$conn=mysql_connect("localhost","root","123456");
if(!$conn){
    echo "connect failed";
    exit;
}
mysql_select_db("big-bak",$conn);
mysql_query("set names utf8");
 
$price=10;
$user_id=1;
$goods_id=1;
$sku_id=11;
$number=1;
 
//生成唯一订单号
function build_order_no(){
  return date('ymd').substr(implode(NULL, array_map('ord', str_split(substr(uniqid(), 7, 13), 1))), 0, 8);
}
//记录日志
function insertLog($event,$type=0){
    global $conn;
    $sql="insert into ih_log(event,type)
    values('$event','$type')";
    mysql_query($sql,$conn);
}
 
$fp = fopen("lock.txt", "w+");
if(!flock($fp,LOCK_EX | LOCK_NB)){
    echo "系统繁忙，请稍后再试";
    return;
}
//下单
$sql="select number from ih_store where goods_id='$goods_id' and sku_id='$sku_id'";
$rs=mysql_query($sql,$conn);
$row=mysql_fetch_assoc($rs);
if($row['number']>0){//库存是否大于0
    //模拟下单操作
    $order_sn=build_order_no();
    $sql="insert into ih_order(order_sn,user_id,goods_id,sku_id,price)
    values('$order_sn','$user_id','$goods_id','$sku_id','$price')";
    $order_rs=mysql_query($sql,$conn);
     
    //库存减少
    $sql="update ih_store set number=number-{$number} where sku_id='$sku_id'";
    $store_rs=mysql_query($sql,$conn);
    if(mysql_affected_rows()){
        insertLog('库存减少成功');
        flock($fp,LOCK_UN);//释放锁
    }else{
        insertLog('库存减少失败');
    }
}else{
    insertLog('库存不够');
}
fclose($fp);

第四种，使用redis队列

<?php

$store=1000;

$redis=new Redis();

$result=$redis->connect('127.0.0.1',6379);

$res=$redis->llen('goods_store');

echo $res;

$count=$store-$res;

for($i=0;$i<$count;$i++){

    $redis->lpush('goods_store',1);

}

echo $redis->llen('goods_store');

?>