smarty缓存终极优化测试之前在看到可以关闭compile_check来减少模板编译文件的判断，这几天看了下 郭欣 的《
smarty缓存终极优化测试
之前在看到可以关闭compile_check来减少模板编译文件的判断，这几天看了下 郭欣 的《构建高性能Web站点》，再次学到好东西。就是放弃smarty自带的缓存文件的判断，直接生成html文件，然后用stat来检查html文件的时间，用来判断是否缓存是否过期。代码类似:
????$cache_filename = 'cache/enjoy_'.$par.'.htm';
????$stat_info = @stat($cache_filename);
????if($stat_info && $stat_info[9] > time()-10800){
????????echo file_get_contents($cache_filename);
????????exit();
????}
????......
????$html = $smarty->fetch($template_name,$par);
????file_put_contents($cache_filename,$html);
????echo $html;
用本机的程序测试了下，本机因为是测试环境，没有装apc。
ab.exe -n 100 -c 10? http://www.itokit.com/
没用使用smarty缓存，就1句速度很快的SQL查询语句
Document Path:??????????/
Document Length:????????16787 bytes
Time taken for tests:?? 1.984 seconds
Total transferred:??????1697100 bytes
HTML transferred:?????? 1678700 bytes
Requests per second:????50.39 [#/sec] (mean)
Time per request:?????? 198.438 [ms] (mean)
Time per request:?????? 19.844 [ms] (mean, across all concurrent requests)
Transfer rate:??????????835.19 [Kbytes/sec] received
使用smarty缓存后：
Time taken for tests:?? 1.891 seconds
Total transferred:??????1697100 bytes
HTML transferred:?????? 1678700 bytes
Requests per second:????52.89 [#/sec] (mean)
Time per request:?????? 189.063 [ms] (mean)
Time per request:?????? 18.906 [ms] (mean, across all
Transfer rate:??????????876.60 [Kbytes/sec] received
没多大提高。
改造之后，但仍然先构造了smarty对象
Time taken for tests:?? 0.688 seconds
Total transferred:??????1697100 bytes
HTML transferred:?????? 1678700 bytes
Requests per second:????145.45 [#/sec] (mean)
Time per request:?????? 68.750 [ms] (mean)
Time per request:?????? 6.875 [ms] (mean, across all concurrent requests)
Transfer rate:??????????2410.65 [Kbytes/sec] received
显著提高啊！
把加载smarty的语句放在判断后：
Time taken for tests:?? 0.391 seconds
Total transferred:??????1697100 bytes
HTML transferred:?????? 1678700 bytes
Requests per second:????256.00 [#/sec] (mean)
Time per request:?????? 39.063 [ms] (mean)
Time per request:?????? 3.906 [ms] (mean, across all concurrent requests)
Transfer rate:??????????4242.75 [Kbytes/sec] received
再次大幅提高！
如果自定义了缓存文件名称，那么删除缓存文件就得另外写一个，不能使用smarty自带的。如果要使用smarty自带的删除功能，那么缓存文件就要使用smarty的方式来命名。如模板文件为index.html，那么生成的缓存文件为：%%77^774^774BE9C9%%index.html，如果加了hx这个$cache_id，那么缓存文件为：hx^%%77^774^774BE9C9%%index.html。这是怎么生成的呢？我根据smarty核心程序中的_get_auto_id和_get_auto_filename函数写了一个生成缓存文件名的一个函数。function get_smarty_cachefile($cache_dir,$template_name,$cache_id=null){
????$_compile_dir_sep = '^';
????$_return = $cache_dir.DIRECTORY_SEPARATOR;
????if(isset($cache_id)) {
????????$auto_id = str_replace('%7C',$_compile_dir_sep,(urlencode($cache_id)));
????????$_return .= $auto_id . $_compile_dir_sep;
????}??
????
????$_filename = urlencode(basename($template_name));
????$_crc32 = sprintf('%08X', crc32($template_name));
????$_crc32 = substr($_crc32, 0, 2) . $_compile_dir_sep .
??????????????substr($_crc32, 0, 3) . $_compile_dir_sep . $_crc32;
????$_return .= '%%' . $_crc32 . '%%' . $_filename;
????return $_return;
}这个函数，未考虑缓存目录分级，如果有使用缓存目录分级$smarty->use_sub_dirs=true，那么只需要把$_compile_dir_sep = '^';改为$_compile_dir_sep =DIRECTORY_SEPARATOR即可。
如上例：????????????
$cache_filename = get_smarty_cachefile('cache',$template_name,'hx');
这样就可以使用$smarty->clear_cache($template_name, 'hx')来删除这个缓存文件。
这样，只需要更改判断是否有缓存的代码，尽量把加载smarty的代码和初始化smarty放到判断之后，其他的不用考虑，就可以享受smarty性能的提升了。
