【发布时间】：2010-12-17 08:32:41
【问题描述】：
我正在使用 APC 将类名映射存储到类文件路径。我在自动加载功能中像这样构建地图：
$class_paths = apc_fetch('class_paths');
// If the class path is stored in application cache - search finished.
if (isset($class_paths[$class])) {
return require_once $class_paths[$class];
// Otherwise search in known places
} else {
// List of places to look for class
$paths = array(
'/src/',
'/modules/',
'/libs/',
);
// Search directories and store path in cache if found.
foreach ($paths as $path) {
$file = DOC_ROOT . $path . $class . '.php';
if (file_exists($file)) {
echo 'File was found in => ' . $file . '<br />';
$class_paths[$class] = $file;
apc_store('class_paths', $class_paths);
return require_once $file;
}
}
}
我可以看到随着越来越多的类被加载，它们被添加到地图中，但在某些时候apc_fetch 在页面请求中间返回NULL，而不是返回地图。
Getting => class_paths
Array
(
[MCS\CMS\Helper\LayoutHelper] => /Users/mbl/Documents/Projects/mcs_ibob/core/trunk/src/MCS/CMS/Helper/LayoutHelper.php
[MCS\CMS\Model\Spot] => /Users/mbl/Documents/Projects/mcs_ibob/core/trunk/src/MCS/CMS/Model/Spot.php
)
Getting => class_paths
{null}
很多时候缓存的值也会在页面请求之间消失。
这可能是什么原因？
我将 APC 用作运行 PHP 5.3 的扩展 (PECL)。
更新： 在下面的 cmets 中，您会看到有人说 APC 不是持久性的并且不值得信任。但在我的情况下，代码在 15-50 毫秒之间在一页请求中执行。难道我不能信任 APC 这么久吗？
更新：
似乎缓存包含具有相同键的多个条目，而它应该只包含一个 - 在调用 apc_store() 时会覆盖该值。我希望这可以帮助某人理解这个问题。 （我已经禁用了满贯防御和写锁）
Array
(
[num_slots] => 4099
[ttl] => 0
[num_hits] => 0
[num_misses] => 3
[num_inserts] => 9678
[expunges] => 0
[start_time] => 1293109072
[mem_size] => 40064
[num_entries] => 8
[file_upload_progress] => 1
[memory_type] => mmap
[locking_type] => file
[cache_list] => Array
(
[0] => Array
(
[info] => fSchema::mysql::fORM::default::/Users/mbl/Documents/Projects/mcs_ibob/core/trunk/public_html/::::column_info
[ttl] => 0
[type] => user
[num_hits] => 0
[mtime] => 1293109072
[creation_time] => 1293109072
[deletion_time] => 0
[access_time] => 1293109072
[ref_count] => 0
[mem_size] => 12456
)
[1] => Array
(
[info] => mcs:odk:class_paths
[ttl] => 3600
[type] => user
[num_hits] => 0
[mtime] => 1293109072
[creation_time] => 1293109072
[deletion_time] => 0
[access_time] => 1293109072
[ref_count] => 0
[mem_size] => 648
)
[2] => Array
(
[info] => mcs:odk:class_paths
[ttl] => 3600
[type] => user
[num_hits] => 0
[mtime] => 1293109072
[creation_time] => 1293109072
[deletion_time] => 0
[access_time] => 1293109072
[ref_count] => 0
[mem_size] => 648
)
[3] => Array
(
[info] => mcs:odk:class_paths
[ttl] => 3600
[type] => user
[num_hits] => 0
[mtime] => 1293109072
[creation_time] => 1293109072
[deletion_time] => 0
[access_time] => 1293109072
[ref_count] => 0
[mem_size] => 648
)
[4] => Array
(
[info] => mcs:odk:class_paths
[ttl] => 3600
[type] => user
[num_hits] => 0
[mtime] => 1293109072
[creation_time] => 1293109072
[deletion_time] => 0
[access_time] => 1293109072
[ref_count] => 0
[mem_size] => 648
)
[5] => Array
(
[info] => mcs:odk:class_paths
[ttl] => 3600
[type] => user
[num_hits] => 0
[mtime] => 1293109072
[creation_time] => 1293109072
[deletion_time] => 0
[access_time] => 1293109072
[ref_count] => 0
[mem_size] => 648
)
[6] => Array
(
[info] => mcs:odk:class_paths
[ttl] => 3600
[type] => user
[num_hits] => 0
[mtime] => 1293109072
[creation_time] => 1293109072
[deletion_time] => 0
[access_time] => 1293109072
[ref_count] => 0
[mem_size] => 648
)
[7] => Array
(
[info] => fSchema::mysql::fORM::default::/Users/mbl/Documents/Projects/mcs_ibob/core/trunk/public_html/::::merged_column_info
[ttl] => 0
[type] => user
[num_hits] => 0
[mtime] => 1293109072
[creation_time] => 1293109072
[deletion_time] => 0
[access_time] => 1293109072
[ref_count] => 0
[mem_size] => 23720
)
)
[deleted_list] => Array
(
)
)
【问题讨论】：
-
@Michael：可能是因为你的缓存已满所以它会丢弃它
-
@RageZ：我只存储了几个字符串。经常/快速点击
apc_store可能是个问题吗？ -
@Michael：我从未使用过 APC，但如果它与 memcache 相同，则无法保证系统将永远保留您的数据。所以我同意 BarsMonster 的回答。
-
@RageZ 但我们仍然在谈论每次命中类自动加载函数之间的毫秒数，APC 必须存储比这更长的值？
-
Gopal（APC 的主要作者之一）最近发表的这篇文章可能会为您的问题提供一些不太技术性的信息（故意发表评论，而不是回答）：phpadvent.org/2010/share-and-enjoy-by-gopal-vijayaraghavan