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aepot
Asked:2024-06-10 17:39:20 +0000 UTC2024-06-10 17:39:20 +0000 UTC

在有扩展的情况下，对数组进行按元素分配的性能是否更好？

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有一个 Mediawiki 配置，众所周知，每个或几乎每个请求都会引发该配置。因此，该配置的性能问题至关重要。

在此配置中，我自定义用户组的访问权限集。

有一组权限user具有一些默认权限，并且在加载配置时它已经存在，然后我修改其权限集。

$wgGroupPermissions['user']['viewmyprivateinfo'] = true;
$wgGroupPermissions['user']['editmyprivateinfo'] = true;
$wgGroupPermissions['user']['editmyoptions'] = true;
$wgGroupPermissions['user']['edit'] = false;
$wgGroupPermissions['user']['createpage'] = false;
$wgGroupPermissions['user']['createtalk'] = false;
$wgGroupPermissions['user']['editmyusercss'] = false;
$wgGroupPermissions['user']['editmyuserjs'] = false;
$wgGroupPermissions['user']['sendemail'] = false;
$wgGroupPermissions['user']['upload'] = false;
$wgGroupPermissions['user']['reupload-shared'] = false;
$wgGroupPermissions['user']['writeapi'] = false;
$wgGroupPermissions['user']['minoredit'] = false;
$wgGroupPermissions['user']['reupload'] = false;
$wgGroupPermissions['user']['move-rootuserpages'] = false;
$wgGroupPermissions['user']['move'] = false;
$wgGroupPermissions['user']['move-categorypages'] = false;
$wgGroupPermissions['user']['move-subpages'] = false;
$wgGroupPermissions['user']['movefile'] = false;
$wgGroupPermissions['user']['applychangetags'] = false;
$wgGroupPermissions['user']['editcontentmodel'] = false;
$wgGroupPermissions['user']['editmyuserjson'] = false;
$wgGroupPermissions['user']['editmyuserjsredirect'] = false;
$wgGroupPermissions['user']['changetags'] = false;

这正是 Mediawiki 文档建议的做法。

但后来，当我第一百次经过这列代码时，我决定可以这样重写：

$wgGroupPermissions['user'] = [
    ...$wgGroupPermissions['user'],
    'viewmyprivateinfo' => true,
    'editmyprivateinfo' => true,
    'editmyoptions' => true,
    'edit' => false,
    'createpage' => false,
    'createtalk' => false,
    'editmyusercss' => false,
    'editmyuserjs' => false,
    'sendemail' => false,
    'upload' => false,
    'reupload-shared' => false,
    'writeapi' => false,
    'minoredit' => false,
    'reupload' => false,
    'move-rootuserpages' => false,
    'move' => false,
    'move-categorypages' => false,
    'move-subpages' => false,
    'movefile' => false,
    'applychangetags' => false,
    'editcontentmodel' => false,
    'editmyuserjson' => false,
    'editmyuserjsredirect' => false,
    'changetags' => false,
];

从可读性的角度来看，这个选项看起来更酷。从性能的角度来看，这两个选项都可以正常工作。

问题：我是否使性能或内存方面的情况变得更糟？

PHP-FPM 8.3 + Nginx + Debian @ Docker

php

1 个回答

  1. Best Answer

    我在网上找不到你问题的答案，所以我写了一个小基准：

    header('Content-Type', 'text/plain');

$startTime = microtime(true);

const attempts = 100000;

for ($i = 0; $i < attempts; $i++) {
    $wgGroupPermissions = ['user' => []];

    $wgGroupPermissions['user']['viewmyprivateinfo'] = true;
    $wgGroupPermissions['user']['editmyprivateinfo'] = true;
    $wgGroupPermissions['user']['editmyoptions'] = true;
    $wgGroupPermissions['user']['edit'] = false;
    $wgGroupPermissions['user']['createpage'] = false;
    $wgGroupPermissions['user']['createtalk'] = false;
    $wgGroupPermissions['user']['editmyusercss'] = false;
    $wgGroupPermissions['user']['editmyuserjs'] = false;
    $wgGroupPermissions['user']['sendemail'] = false;
    $wgGroupPermissions['user']['upload'] = false;
    $wgGroupPermissions['user']['reupload-shared'] = false;
    $wgGroupPermissions['user']['writeapi'] = false;
    $wgGroupPermissions['user']['minoredit'] = false;
    $wgGroupPermissions['user']['reupload'] = false;
    $wgGroupPermissions['user']['move-rootuserpages'] = false;
    $wgGroupPermissions['user']['move'] = false;
    $wgGroupPermissions['user']['move-categorypages'] = false;
    $wgGroupPermissions['user']['move-subpages'] = false;
    $wgGroupPermissions['user']['movefile'] = false;
    $wgGroupPermissions['user']['applychangetags'] = false;
    $wgGroupPermissions['user']['editcontentmodel'] = false;
    $wgGroupPermissions['user']['editmyuserjson'] = false;
    $wgGroupPermissions['user']['editmyuserjsredirect'] = false;
    $wgGroupPermissions['user']['changetags'] = false;

    unset($wgGroupPermissions);
}

$endTime = microtime(true) - $startTime;

echo $endTime . PHP_EOL;
echo memory_get_usage() . PHP_EOL;

$startTime = microtime(true);

for ($i = 0; $i < attempts; $i++) {
    $wgGroupPermissions = ['user' => []];

    $wgGroupPermissions['user'] = [
        ...$wgGroupPermissions['user'],
        'viewmyprivateinfo' => true,
        'editmyprivateinfo' => true,
        'editmyoptions' => true,
        'edit' => false,
        'createpage' => false,
        'createtalk' => false,
        'editmyusercss' => false,
        'editmyuserjs' => false,
        'sendemail' => false,
        'upload' => false,
        'reupload-shared' => false,
        'writeapi' => false,
        'minoredit' => false,
        'reupload' => false,
        'move-rootuserpages' => false,
        'move' => false,
        'move-categorypages' => false,
        'move-subpages' => false,
        'movefile' => false,
        'applychangetags' => false,
        'editcontentmodel' => false,
        'editmyuserjson' => false,
        'editmyuserjsredirect' => false,
        'changetags' => false,
    ];

    unset($wgGroupPermissions);
}

$endTime = microtime(true) - $startTime;

echo $endTime . PHP_EOL;
echo memory_get_usage() . PHP_EOL;
exit;

    事实证明，具有价差的选项更加省时：

    0.02248477935791
347272
0.014714956283569
347272

    但前提是我们每次都为数据集调用 unset() 。根据记忆，这两个选项具有相同的消耗，这很可能是由于数组中元素的数量造成的。如果去掉unset()并将数组的初始化从循环中取出，那么图片会变成这样：

    0.013426780700684
349288
0.01802396774292
349288
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