芳草苑

Author: 芳草苑主

  • When does php apc refresh cache data?

    I did this experiment with php apc:

    In php.ini I set include_path = /first/include/path:/second/include/path, but do not put a file in /first/include/path or /second/include/path, create test.php as simple as this

    <?php
require 'tobeincluded.php';

    It will run into a fatal error. This error is obvious.

    Then I create the file tobeincluded.php in /second/include/path, test.php now runs all right.

    Then I create another file with same file name as tobeincluded.php but different content and put it in /first/include/path, test.php keeps running as if /first/include/path/tobeincluded.php does not exist. This is because php apc has cached /second/include/path/tobeincluded.php and ignored /first/include/path/tobeincluded.php. Apc will refresh its cache when it is restarted or original cached file is updated in the file system. I assume apc is checking file timestamp.

    Then I copy test.php to test2.php and put test2.php in the same folder as test.php, run test2.php. It renders the same result as test.php – include /second/include/path/tobeincluded.php but ignore the existence of /first/include/path/tobeincluded.php.

    Then I copy test.php to test3.php and put test3.php in a different folder (no matter parent folder or child folder or irrelevant folder), run test3.php. Now it is aware of the existence of /first/include/path/tobeincluded.php so /first/include/path/tobeincluded.php is included in test3.php.

    Even I trigger to run test2.php in a different virtual host (but same document root), it still renders the same result. I assume php file on the file system is identical to apc. In other words, apc loads cache data by realpath regardless virtual host.

  • Magento does not remove storeview data when scope changes

    今天我做了个有趣的实验：

    1. 首先 Manage Attributes，设置某 product attribute ‘my_attr’ scope 为 Store view
    2. 然后 Manage Products，为 my_attr 设置 default value ‘aaa’，再设置 store view (假设 storeId = 2) value ‘bbb’
    3. 然后 Manage Attributes， 把 my_attr scope 改为 Global
    4. 然后 Manage Products，Choose Store View (storeId = 2)，这时仍可见 my_attr 显示值 ‘bbb’。It means although my_attr scope is changed to ‘Global’, but old store view specific values are not removed.
    5. 这时 (my_attr scope is Global) 如果在 Store View (storeId = 2) 状态把 my_attr 的值改为 ‘ccc’，then Save Product。my_attr default value 被改为 ‘ccc’，store view (storeId = 2) value 仍为 ‘bbb’。It means when my_attr scope is ‘Global’, it is not possible using Manage Products GUI to change or remove existing store view value.

    摸清 Magento 的规律后就容易理解 Manage Products GUI 在 scope 改变或 store view 切换时的行为。另文有提及 change product default value and store view view by programming.

  • Skype banned Fring

    不久前注意到我的 fring addon 里 skype 突然就不见了，我没上心去究其原因。今天在 fring 官网看到：

    Skype no longer on fring
    Skype no longer on fring

    我搜了几则关于 fring skype 的消息，就明白了——skype 把 fring 给禁了。

    我用 fring 就是因为手机上用不了 skype：在 iphone 上装 fring 是因为无需 jail break 就能通过 fring 中转的 skype 支持 voip over 3g；在 android 上装是因为 skype 的开发速度太慢，刚用 android 时 skype 根本没有 skype for android。今天我又重新上 skype 去看，倒是开始支持某些 android 手机，可惜我的 g1 仍不支持。所以，在我看来，skype 禁了 fring 有点损人不利己。

    这让我对 skype 再次失望：一个公司技术力量有限情有可原，但如果它的经营哲学是用技术限制去阻止用户享受更好的服务，那就没有救了，一切营销手段在这种哲学的指导下都是缘木求鱼。

    I am lucky because skype is not my main voip service provider. Whatever restrictions skype put on to its users won’t affect my life, but get away from skype quicker.

  • What is Google Wave?

    董总问我，什么是 Google Wave？

    这问题问得好，我一时不晓得怎么回答，我知道他问这个问题不是问 Google Wave 的定义。要泛泛了解 Google Wave，何必问我，去看看 Google Wave Help 或者上 YouTube 看几个入门的 video 就可以。

    那么换句话问，在各种交流方式层出不穷的今天，Google Wave 有什么独到的地方？我们已经有了 email (of course I refer to Gmail), IM, SNS；Google 通讯产品也出了不少，gmail, gtalk, orkut, voice, buzz, 现在又出了 wave。很多产品，比如 facebook, twitter 据称很火爆的产品我都没来得及用。这也说明一个问题，大部分产品都有独到的地方，即便火爆，但它们无法象 email 一样不可或缺，从而改变世界。

    Google Wave logo
    Google Wave logo

    就功能而言，Google Wave 高出 gmail 很多，比如即时、自主、互动，等等特性，在 Google Wave introduction 里都有提及，不用我多说。我自己在使用 gmail 时碰到的问题是：尽管gmail很智能，但无法按自定义的、更多的线索归类。我想 Google Wave 更灵活，能弥补 gmail 的不足。但现在使用 Google Wave 的缺陷是必须拉对方进入 wave 才能共同享受 wave。我想如果能把 gmail 作为 wave object，发起人能单方面 wave by email，即使对方不加入 wave，发起人也能 enjoy wave，这样 wave 就完美了。

    要不然，在还没有人手一个 wave 的今天，wave 就无法取代 gmail。要是我们还得开一个 tab 用 Google Wave，另一个 tab 用 gmail，那么反过来也会影响 Google Wave 的普及。我期盼着一个能把 gmail 取而代之的 Google Wave。

  • Class Mage_Sales_Model_Entity is deprecated

    今天终于搞清楚了一件困扰我已久的问题：在 Magento Sales Module 下有两个分支 Mage_Sales_Model_Entity 和 class Mage_Sales_Model_Mysql4，看上去文件结构比较相似，Sales 和其他模块一时用 Mage_Sales_Model_Entity，一时又用 Mage_Sales_Model_Mysql4。它们有什么区别？为什么要同时存在？有必要同时存在吗？如要删除一个，该删哪个保留哪个？

    以前有个任务，想要给 order 等 entity 添加一些自定义属性，因为搞不清楚哪个在起作用，我把两个类都 extends 了，即 class Mage_Sales_Model_Entity_Setup 和 class Mage_Sales_Model_Mysql4_Setup。而因为其他一些原因，自定义属性并不能完全按照我的意愿工作，所以我也没办法再用替换法去测试哪个类在起作用。

    今天重新回顾了这个问题，摸清 Mage_Sales_Model_Entity is deprecated。When extending sales entity, only need to extend classes in Mage_Sales_Model_Mysql4.

    但是简单地删除 magento/app/code/core/Mage/Sales/Model/Entity 目录则会导致程序找不到必要的文件而出错。我的建议是了解 Mage_Sales_Model_Entity is deprecated 这个事实就可以了，如果一定想割了这个阑尾目录，得做一些调整：

    • 搜索一下哪些 class extends Entity 下的类 (search for Mage_Sales_Model_Entity under magento folder)，把它们改成 extends Mysql4 下对应的类。据我搜索结果，只有 Mage_Reports 一些 class extends Entity 下的类，或许 Mage_Sales 在 Mage_Reports 成形之后进行 Entity to Mysql4 的调整，而为了省事，保留 Entity 下的类，就不用去修改 Mage_Reports 了。
    • 搜索一下哪些地方用到了 getModel(‘sales_entity/entity_name’) 的方式，把它们改成 getModel(‘sales_mysql4/entity_name’)。这需要同时搜索文件和数据库（数据库里 eav_attribute 有几个 backend models 是这样被引用的）。如果嫌这么替换比较麻烦，也可以修改 magento/app/code/core/Mage/Sales/etc/config.xml，把 <sales_entity><class>Mage_Sales_Model_Entity</class></sales_entity> 修改成 <sales_entity><class>Mage_Sales_Model_Mysql4</class></sales_entity>，这样就把 sales_entity model 与 sales_mysql4 model 等价起来了。

  • Android pdf viewer

    为了在 Android 打开 pdf 文档，我曾从 Android Market 里找了一个 PDF Viewer，幸好有免费的版本，安装也不困难。

    最近发现 Android G1 随即自带的 QuickOffice 就支持 pdf 阅读，速度还比 PDF Viewer 快，我当初怎么就没想到它？真是糊涂！

    回想一下，我糊涂也是有原因的：在 Android 到手前我还研究过怎么在 iphone 上看 pdf，花了一晚上时间也没找到一个可行的办法，忿忿地放弃（其实也没什么好忿忿的，iphone 本来就不好用，apple app store 里也没几个好软件是免费的）。Android 到手之后我就沿袭了 iphone 的研究方法，在 Android Market 很快找到了一个应用，很快地解决问题，再也没去想原来 Android 还有更现成的方案。

  • Google Contacts synchronisation fails on my Android after Google Mail became Gmail

    Google announced Google Mail is becoming Gmail in the UK in May. Then some day I decided to swap over my Google Account primary email address from @googlemail.com to @gmail.com. Everything continues to work as before. It should be working because I assume googlemail.com or gmail.com is alias to the other.

    After quite a long time (at least 2 weeks), I noticed Google Contacts stopped synchronisation from 28 May, 2008. Because Google Mail and Google Calendar continued to work all right, so I did not think it was problem of my Google Account change. I did not regard the domain name swap was a change. I thought it was merely Google was updating Google Contacts programme or server something.

    I have been waiting for Google Contacts synchronisation back to normal for a month. During the month I googled quite often if someone else encountered the same problem, but I did not find a case like mine.

    I could not live up with a situation that I had to enter a new contact twice any longer, so I started investigating harder. And only by change I realised it might be a problem caused by domain name swap. Then how to change Google Account information stored on my Android? I find it is not straight forward.

    First there is no interface for change the Google Account on Android. Someone mentioned a tricky method by changing the Google Account password then reboot Android. But it did not work on my Android G1. After reboot, it only pop up a box to enter password, not for account username.

    I manage to change Google Account by clicking Setup -> Applications -> Manage applications -> Google Apps -> Clear data, then reboot. Clear Google Apps data clear all contacts on Android as well, but it is not a problem for me because I have all contacts in google cloud anyway.

    A by-product of my investigation is I find Android support Google Apps Account as normal Google Account, which makes me very happy because I use Google Apps Account much more than Google Account.

  • Upgrade zend server php 5.2 to 5.3

    The correct command to remove php 5.2 before upgrade zend server to 5.3 is

    yum -y remove zend-server-php-5.2 && yum -y remove `rpm -qa|grep zend|xargs`

    Use yum -y remove zend-server-php-5.2 is not enough.

    After removal, run

    yum install zend-server-ce-php-5.3

    Of course, zend repository must be add to /etc/yum.repos.d before. (If not, where you got zend server php 5.2?)

    The most recent /etc/yum.repos.d/zend.repo is

    [Zend]
    name=Zend Server
    baseurl=http://repos.zend.com/zend-server/rpm/$basearch
    enabled=1
    gpgcheck=0

    [Zend_noarch]
    name=Zend Server – noarch
    baseurl=http://repos.zend.com/zend-server/rpm/noarch
    enabled=1
    gpgcheck=0

    I notice it was changed since my first copy. It was

    [Zend]
    name=Zend CE $releasever – $basearch – Released Updates
    baseurl=http://repos.zend.com/rpm/ce/$basearch/
    enabled=1
    gpgcheck=0
    [Zendce-noarch]
    name=Zend CE – noarch
    baseurl=http://repos.zend.com/rpm/ce/noarch
    enabled=1
    gpgcheck=0

    Old copy no long work with command
    yum install zend-server-ce-php-5.3

  • 1and1 cloud server datasheet

    从 1&1 新订了一个合同，cloud server，就是为了让 magento 跑快一些。那 1and1 的 cloud server 究竟能有多快呢？

    先看看 cat /proc/cpuinfo 的情况
    processor : 0
    vendor_id : AuthenticAMD
    cpu family : 16
    model : 2
    model name : Quad-Core AMD Opteron(tm) Processor 2352
    stepping : 3
    cpu MHz : 2109.718
    cache size : 512 KB
    fpu : yes
    fpu_exception : yes
    cpuid level : 4
    wp : yes
    flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat clflush mmx fxsr sse sse2 syscall mmxext fxsr_opt lm 3dnowext 3dnow pni cx16 popcnt lahf_lm cr8_legacy altmovcr8 abm sse4a misalignsse
    bogomips : 4219.43
    TLB size : 1024 4K pages
    clflush size : 64
    cache_alignment : 64
    address sizes : 48 bits physical, 48 bits virtual
    power management:

    processor : 1
    vendor_id : AuthenticAMD
    cpu family : 16
    model : 2
    model name : Quad-Core AMD Opteron(tm) Processor 2352
    stepping : 3
    cpu MHz : 2109.718
    cache size : 512 KB
    fpu : yes
    fpu_exception : yes
    cpuid level : 4
    wp : yes
    flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat clflush mmx fxsr sse sse2 syscall mmxext fxsr_opt lm 3dnowext 3dnow pni cx16 popcnt lahf_lm cr8_legacy altmovcr8 abm sse4a misalignsse
    bogomips : 4220.53
    TLB size : 1024 4K pages
    clflush size : 64
    cache_alignment : 64
    address sizes : 48 bits physical, 48 bits virtual
    power management:

    processor : 2
    vendor_id : AuthenticAMD
    cpu family : 16
    model : 2
    model name : Quad-Core AMD Opteron(tm) Processor 2352
    stepping : 3
    cpu MHz : 2109.718
    cache size : 512 KB
    fpu : yes
    fpu_exception : yes
    cpuid level : 4
    wp : yes
    flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat clflush mmx fxsr sse sse2 syscall mmxext fxsr_opt lm 3dnowext 3dnow pni cx16 popcnt lahf_lm cr8_legacy altmovcr8 abm sse4a misalignsse
    bogomips : 4223.97
    TLB size : 1024 4K pages
    clflush size : 64
    cache_alignment : 64
    address sizes : 48 bits physical, 48 bits virtual
    power management:

    processor : 3
    vendor_id : AuthenticAMD
    cpu family : 16
    model : 2
    model name : Quad-Core AMD Opteron(tm) Processor 2352
    stepping : 3
    cpu MHz : 2109.718
    cache size : 512 KB
    fpu : yes
    fpu_exception : yes
    cpuid level : 4
    wp : yes
    flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat clflush mmx fxsr sse sse2 syscall mmxext fxsr_opt lm 3dnowext 3dnow pni cx16 popcnt lahf_lm cr8_legacy altmovcr8 abm sse4a misalignsse
    bogomips : 4219.25
    TLB size : 1024 4K pages
    clflush size : 64
    cache_alignment : 64
    address sizes : 48 bits physical, 48 bits virtual
    power management:

    在 cloud server 上我使用 zend server。我特意从 1 Virtual processor core 1GB Ram 一步步往上加，使用 ab -c 5 -n 500 对比测试，客户端是 10 Mb down stream / 1Mb up stream adsl 连接。

    在 1 Virtual processor core 1GB Ram 时，Requests per second: 5.31 [#/sec]
    在 2 Virtual processor cores 1GB Ram 时，Requests per second: 8.34 [#/sec]
    在 2 Virtual processor cores 2GB Ram 时，Requests per second: 8.26 [#/sec]
    在 3 Virtual processor cores 1GB Ram 时，Requests per second: 10.57 [#/sec]
    在 4 Virtual processor cores 1GB Ram 时，Requests per second: 11.33 [#/sec]

    在 shopping cart 里有 7 条不同商品时，checkout/cart/index 页面时间为 10 秒左右。

    回头看看老 server
    # cat /proc/cpuinfo
    processor : 0
    vendor_id : AuthenticAMD
    cpu family : 15
    model : 67
    model name : Dual-Core AMD Opteron(tm) Processor 1216 HE
    stepping : 3
    cpu MHz : 1000.000
    cache size : 1024 KB
    physical id : 0
    siblings : 2
    core id : 0
    cpu cores : 2
    apicid : 0
    initial apicid : 0
    fpu : yes
    fpu_exception : yes
    cpuid level : 1
    wp : yes
    flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt rdtscp lm 3dnowext 3dnow rep_good nopl pni cx16 lahf_lm cmp_legacy svm extapic cr8_legacy
    bogomips : 1999.96
    TLB size : 1024 4K pages
    clflush size : 64
    cache_alignment : 64
    address sizes : 40 bits physical, 48 bits virtual
    power management: ts fid vid ttp tm stc

    processor : 1
    vendor_id : AuthenticAMD
    cpu family : 15
    model : 67
    model name : Dual-Core AMD Opteron(tm) Processor 1216 HE
    stepping : 3
    cpu MHz : 1000.000
    cache size : 1024 KB
    physical id : 0
    siblings : 2
    core id : 1
    cpu cores : 2
    apicid : 1
    initial apicid : 1
    fpu : yes
    fpu_exception : yes
    cpuid level : 1
    wp : yes
    flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt rdtscp lm 3dnowext 3dnow rep_good nopl pni cx16 lahf_lm cmp_legacy svm extapic cr8_legacy
    bogomips : 1999.96
    TLB size : 1024 4K pages
    clflush size : 64
    cache_alignment : 64
    address sizes : 40 bits physical, 48 bits virtual
    power management: ts fid vid ttp tm stc

    运行的是 nginx，同等条件下，Requests per second: 8.12 [#/sec]，checkout/cart/index 页面生成时间也是 10 秒左右。

    虽 zend server 和 nginx 不同，靠不是完全对等的对比结果，我还是可以得出两个结论：

    1. 瓶颈仍是 cpu 速度；
    2. cloud server 并未显著提高速度，我对它预期过高，略有失望。

  • How to detect current connection is secure using Php?

    Over a long time I had believed there was a function or an environment variable I could use in Php to tell whether the current connection secure or not, i.e. a page requested via http or https protocol. Unfortunately I could not find a good solution. I can not find it does not mean it does not exist.

    Recently I intend to believe the perfect solution does not exist, i.e. I can not write something in Php safely to tell whether the current connection is secure unless I know the server setting.

    Look at the code snippet Magento use for isSecure function:

    $secure = (!empty($_SERVER['HTTPS']) && ($_SERVER['HTTPS']!='off')) || $_SERVER['SERVER_PORT']=='443';

    This code is not perfect because it assumes the server is not listening http on 443 AND server is listening HTTPS on 443.

    Unfortunately I can not do more than that. I am wondering whether the situation is the same in Python or Java.