Category: 小小草

Magento 1.5.0.0 目前还是 alpha2 版，因为安装到第二步就有一个很明显的 bug，本来想等等再用的。

可是 1.4.2.0 正式版 dataflow profile 跑不起来，一点 “Run Profile in Popup”，出来的 popup 就是空白。我很喜欢用外部编辑器格式化好数据，然后用 dataflow import 到 Magento 数据库。我有很多 modules 也用到 dataflow 来完成初始化，如果 dataflow 跑不起来，会给我造成很大的麻烦。

联想到 Magento 1.5.0.0 在 release note 里说到它对 dataflow 作了改进，我想很可能修正了 1.4.2.0 带来的 bug。两害取其轻，所以我跳过 Magento 1.5.0.0 的全新安装过程，用 1.4.2.0 的数据库让 Magento 1.5.0.0 跑了起来。果然如我所料，dataflow profile 在 1.5.0.0 下工作正常。

Magento 1.5.0.0 alpha2 出来了，我下载来尝鲜。可是，安装到第二步就进行不下去了。提示是：

There was a problem proceeding with Magento installation.

Please contact developers with error messages on this page.

Notice: Undefined variable: params in /path/to/magento/app/code/core/Mage/Core/Block/Html/Select.php on line 142

这挺令人失望的。

There are some website benchmark tools, looking after various aspects of performance.

The tool I use most is Apache Benchmark, and parameters are 10 concurrencies, e.g.

ab -c 10 -n 200 (page_url)

It reflects the status quo. I have a decent server but the sites are not busy.

Since I dived into Magento, I have been spent quite a lot researching how to improve its speed. I implemented database query cache, enabled block html cache, utilised memcache, tmpfs, apc, etc, etc. Recently I started a project called Full Page Cache Preparer (FPCP) and expected it fundamentally improve Magento speed on Catalog and Cms pages.

FPCP is only 20% completion (it is not producing all blocks with session variables, but shopping cart sidebar), but I am eager to see some result. So I turn it on and compare the Requests Per Second to the time when it is off. I see a marginal 1-2% improvement which is very disappointing.

Why I had the impression that full page cache feature will dramatically drive Magento faster? What if full page cache is working with web server cache, say nginx ncache? I simulate a test by saving a page html source code to a static file and uploading it to web server. (I should have done this test before I started FPCP project.) The result is disappointing, again.

The test is done on a heavy page (with loads of images).

The figures in first two columns (ADSL connection) go up and down when I run tests again and again. Sometimes requesting a static file is even slower than requesting Magento index.php. My conclusion is, even when Magento full page cache is working in conjunction with nginx ncache, I cannot feel the sites are faster (when the server load is not high).

However, I will finish my FPCP module (some day) because I believe it benefits people whose server load is high. To improve my own sites, I will focus on basic (if I call FPCP hi-tech) page speed recommendations, e.g., optimise images, concurrent downloads, cookieless domains for static files, merge js/css files, gzip, etc.

Magento did not mention this (or hide somewhere I could not find), so I’d like to mention it:

Magento helper class is a singleton desin pattern. Whether a helper class is called in a format as

Mage::helper('mymodule')->helperMethod();

or as (in a block class or a template),

$this->helper('mymodule')->helperMethod();

the helper class is only initialised once.

Which means Magento puts a singleton desin pattern on helpers.