我的一个事务代码里有三个数据操作，一个查询，两个添加。
末尾加上事务回滚。但是有一个添加数据成功添加，还一个是正常反应没有添加，怎么回事？
public function test(){
$params['id']=23;
$_tran = M();
$_tran->startTrans();
//定义状态判断变量，如果$doCommit为真，则提交事务
$doCommit = true;
//1.获取订单信息
$StoreBuy = M('StoreBuy');
unset($map);
$map['id'] = $params['id'];
$map['status'] = '2';
$storebuy = $StoreBuy->where($map)->find();
if(!$storebuy){$msg = isset($msg)?$msg:"MSG_GET_STOREBUY_INFO_ERROR";$doCommit = false;}
//1.1不能购买自己出售的积分
if($storebuy['sid']==session(C('S_ID'))){
$msg = isset($msg)?$msg:"MSG_NOT_BUY_OWNER_SELL";$doCommit = false;
}

$LogJifen = M('LogJifen');
$data['jifen'] = "110001";
$rs = $LogJifen->add($data);
if(!$rs){$msg = isset($msg)?$msg:"MSG_ADD_JIFENLOG_ERROR";$doCommit = false;}

$Test = M('Test');
$data['number'] = '600';
$rs = $Test->add($data);
if(!$rs){$msg = isset($msg)?$msg:"MSG_ADD_JIFENLOG_ERROR";$doCommit = false;}

var_dump($_tran);
$doCommit=false;
var_dump($doCommit);

//提交事务
if ($doCommit) {
$_tran -> commit();
//jump('/Member/jifenmag/query_type/mybuylist',2, '购买积分成功，页面跳转中...','/Member/msgbox');
} else {
$_tran -> rollback();
//jump(go,2,L($msg),'/Member/msgbox');
}
}