Complete guide to nikond90 digital SLR photography Complete guide to improving PHP speed

One of the advantages of PHP is that it is very fast, which can be said to be sufficient for general website applications. However, if the site's traffic is high, bandwidth is narrow, or other factors cause performance bottlenecks on the server, you may have to think of other ways to further increase the speed of PHP. This article will introduce how to do this from several aspects, so as to make users browse more "cool".
Code Optimization
I don’t want to tell you again how to write cleaner code here. I think everyone knows this. When speed is needed, you may have done a lot of work on optimizing PHP source code. What is proposed here is that this tedious work can be completed by other tools. This is Zend Optimizer, a program available for free from Zend Technologies' website (http://www.zend.com/). Its principle is simple, by detecting the intermediate code generated by the Zend engine and optimizing it to obtain higher execution speed. I think optimizing code is a rather tedious task, and the optimized code may become difficult to understand, especially when you put down the PHP program for a while and suddenly the customer asks you to make some changes, you may not know what to do yourself. understood;-). Therefore, I recommend that you use Zend Optimizer to do this optimization work when the PHP source code is relatively complex. The advantage is that it will not make your code complicated and difficult to understand.
　Installing Zend Optimizer is very simple. Just download the relevant precompiled libraries according to the platform you are using, add two lines to your php.ini, and restart your web server!
zend_optimizer.optimizati
zend_extension="/path/to/ZendOptimizer.so"
zend_loader.enable=Off
　You may be a little surprised, didn't it say two lines, why did it become three lines. However, the third line is optional. It seems that disabling this zend_loader will make the optimization faster, so you might as well add this line to your php.ini file. It should be noted that zend_loader can only be disabled when you are not using Zend Encoder Runtime. Zend Encoder Runtime will be mentioned below.
Want it faster? Use cache
If your PHP application still needs faster speed, the next solution is buffering. There are a few different ways to accomplish this. I myself have tried Zend Cache (evaluation version), APC and Afterburner Cache.
　The above mentioned are all "buffer modules".Their principles are similar. When the PHP file is requested for the first time, by storing the intermediate code of your PHP source code in the memory of the web server, for the same subsequent requests, the "compiled" version in the memory is directly provided. Since it can minimize disk access, this method can indeed greatly improve the performance of PHP. What's more convenient is that when your PHP source code is modified, the buffered module can detect these changes and reload the same, so you don't have to worry about customers getting an old version of the program. These buffered modules are great, but which one should I choose? Let’s introduce them respectively:
Zend Cache is a commercial product of Zend Technologies (it is also the company that provides us with PHP engine and Zend Optimizer for free). It's really good. After the first run, you can obviously notice that the speed of PHP has been greatly improved, and the server has more free resources. The downside is that you have to pay for it, but in terms of value for money, it's still well worth it.
　Afterburner Cache is a free buffer module provided by Bware Technologies (http://bwcache.bware.it/). Currently only a beta version, it seems to do the same job as Zend Cache, but the performance improvement is not as good as Zend Cache, and the existing version does not work with Zend Optimizer, but it is free.
　APC (Alternative PHP Cache) is another free module provided by Community Connect (http://apc.communityconnect.com/). It works very stably and the speed has been greatly improved. It should be noted that I have not found an official test data. These are just tests on my application, so I cannot draw a conclusion.
Compression of Web content (making it more "enjoyable" for your customers to use)
After the above two methods, I believe that the performance of your PHP application has been greatly improved. Now it is time to consider it from another aspect: downloading speed. If your application is only running within the company, and all customers use 100Mb/s Ethernet to connect to the server, this may not be a problem, but if some of your customers use slow modem connections, you need to consider Use content compression method. According to IETF specifications, most browsers support gzip content compression. This means that you can use gzip to compress the web content before sending it to the client's browser. The browser will automatically decompress the data when receiving it and allow the user to see the original page. Likewise, there are several different methods for compressing the content of web pages.
　mod_gzip is an Apache module provided free of charge by Remote Communications (http://www.phpbuilder.com/columns/www.remotecommunications.com), which can compress static web pages. It works just fine, you just need to compile it with apache (or use it as a DSO). People from Remotecommunications said that it can also compress dynamic content, including mod_php, mod_perl, etc. But I tried it, and it doesn't seem to work. I read on the mod_gzip mailing list that this bug will be fixed in the next version (I think it will be version 1.3.14.6f). But you can still use it for static content compression.
　However, we also want to compress dynamic content, so we must find another way. One way is to use class.gzip encode.php (http://leknor.com/code/). Just call this PHP class at the beginning and end of your PHP script to compress your page content. If your entire site requires such compression, you can call these functions in auto_prepend and auto_append in your php.ini file. It works pretty well, but on heavily loaded sites it obviously comes with a bit of overhead. To learn more about how it works, take a look at its class code (you'll need to at least compile PHP with zlib support). The author's instructions inside are also very detailed, so you can get everything you need to know.
Recently, I also saw an article about PHP output buffering. What it says is that PHP4.0.4 has introduced a new output buffer processing method-ob_gzhandler. Its function is the same as the class introduced above, but the difference is that you only need to use the following syntax in your php.ini. :
output_handler = ob_gzhandler ;
　This will activate PHP's output buffering feature and compress everything it sends. For some special reasons, if you don't want to set it here and only change the default setting where needed (no compression), just modify the .htaccess file in the PHP source code directory that needs to be compressed. The syntax used is as follows:
php_value output_handler ob_gzhandler
... Or call it directly in your PHP code, in the following way:
ob_start("ob_gzhandler");
This method of output buffering is good and does not Brings additional system overhead to the server. I highly recommend you use this method. Its change can be illustrated by the following example. If the customer is using a 28.8K modem, after this process, he will think that he has suddenly switched to an ISDN access. One thing to note is: Netscape Communicator does not support image compression, so it will not be displayed.So unless your customers all use Internet Explorer, you must disable compression of jpeg and gif images. There should be no problem with the compression of other files, but I suggest you test it, especially if the browser uses uncommon plug-ins or is a browser that is rarely used.
Other useful stuff...
　Zend Technologies’ online store was launched on January 24 this year and sells some interesting PHP-related products. Including the aforementioned Zend Cache and Zend Encoder (simply put, it is a compiler for PHP code that can generate compiled classes so that you can sell them to customers without worrying about leaking source code. In the web server that needs to run these classes (will use Zend Encoder Runtime for decoding), Zend Ide (an integrated development environment for PHP with many powerful features), and support services for PHP developers.
Conclusion
Using the techniques mentioned in this article, you will be able to greatly improve the performance of your site, but please note the following points:
1. The bottleneck may not be PHP, you need to examine every object in the application (such as database)
2. The performance of a web server is limited. Therefore, do not think that poor performance is due to PHP. It may also be due to a large number of visits. Your server needs to be upgraded, or consider using a load balancing system (change It will cost a lot of money)
3. Don’t think that content compression is not important. In a 100Mb/s LAN, your PHP application may perform very well, but you must consider users who use slow modems.

The above introduces the complete guide to nikond90 digital SLR photography and the complete guide to improving PHP speed, including the complete guide to nikond90 digital SLR photography. I hope it will be helpful to friends who are interested in PHP tutorials.