Foreach() 和 each() 运行 内存不足,分块不起作用
Foreach() and each() running out of memory, chunking not working
我正在编写一个 artisan 控制台命令,循环遍历 table 中的所有记录并在 table 上重新生成一个字段。
该字段是一个 hash
并作为特定字符串的 md5()
生成。
最初我的代码是这样的:
// Get all recipes
$recipes = Recipe::all();
$hashProgress = $this->output->createProgressBar(count($recipes));
// Loop over each recipe and generate a new hash for it
foreach ($recipes as $recipe)
{
$hashString = '';
$hashString .= $recipe->field1;
$hashString .= $recipe->field2;
$hashString .= $recipe->field3;
$hashString .= $recipe->field4;
$hashString .= $recipe->field5;
$hashString .= $recipe->field6;
$hashString .= $recipe->field7;
$extras1Total = $recipe->extras1->sum('amount');
$hashString .= $recipe->extras1->reduce(function ($str, $item) use ($extras1Total) {
return $str . $item->name . ($extras1Total == 0 ? $item->amount : ($item->amount / $extras1Total * 100));
}, '');
$extras2Total = $recipe->extras2->sum('amount');
$hashString .= $recipe->extras2->reduce(function ($str, $item) use ($extras2Total) {
return $str . $item->name . ($extras2Total == 0 ? $item->amount : ($item->amount / $extras2Total * 100));
}, '');
$extras3Total = $recipe->extras3->sum('amount');
$hashString .= $recipe->extras3->reduce(function ($str, $item) use ($extras3Total) {
return $str . $item->name . ($extras3Total == 0 ? $item->amount : ($item->amount / $extras3Total * 100));
}, '');
$extras4Total = $recipe->extras4->sum('amount');
$hashString .= $recipe->extras4->reduce(function ($str, $item) use ($extras4Total) {
return $str . $item->name . ($extras4Total == 0 ? $item->amount : ($item->amount / $extras4Total * 100));
}, '');
$recipe->update([
'hash' => md5($hashString),
]);
$hashProgress->advance();
}
$hashProgress->finish();
$this->info(' Recipe hashes regenerated.');
在达到 28,000 条记录中的大约 10,000 条后,它将因内存耗尽错误而死掉:
PHP Fatal error: Allowed memory size of 268435456 bytes exhausted (tried to allocate 4096 bytes)
我认为 chunk
这样做可能会有帮助:
// Get all recipes
$recipes = Recipe::all();
$hashProgress = $this->output->createProgressBar(count($recipes));
// Loop over each recipe and generate a new hash for it
foreach ($recipes->chunk(1000) as $chunk)
{
foreach ($chunk as $recipe)
{
$hashString = '';
$hashString .= $recipe->field1;
$hashString .= $recipe->field2;
$hashString .= $recipe->field3;
$hashString .= $recipe->field4;
$hashString .= $recipe->field5;
$hashString .= $recipe->field6;
$hashString .= $recipe->field7;
$extras1Total = $recipe->extras1->sum('amount');
$hashString .= $recipe->extras1->reduce(function ($str, $item) use ($extras1Total) {
return $str . $item->name . ($extras1Total == 0 ? $item->amount : ($item->amount / $extras1Total * 100));
}, '');
$extras2Total = $recipe->extras2->sum('amount');
$hashString .= $recipe->extras2->reduce(function ($str, $item) use ($extras2Total) {
return $str . $item->name . ($extras2Total == 0 ? $item->amount : ($item->amount / $extras2Total * 100));
}, '');
$extras3Total = $recipe->extras3->sum('amount');
$hashString .= $recipe->extras3->reduce(function ($str, $item) use ($extras3Total) {
return $str . $item->name . ($extras3Total == 0 ? $item->amount : ($item->amount / $extras3Total * 100));
}, '');
$extras4Total = $recipe->extras4->sum('amount');
$hashString .= $recipe->extras4->reduce(function ($str, $item) use ($extras4Total) {
return $str . $item->name . ($extras4Total == 0 ? $item->amount : ($item->amount / $extras4Total * 100));
}, '');
$recipe->update([
'hash' => md5($hashString),
]);
$hashProgress->advance();
}
}
$hashProgress->finish();
$this->info(' Recipe hashes regenerated.');
但我仍然遇到内存耗尽错误。
如何在不增加内存限制的情况下遍历所有这些记录并实现我所追求的目标?
您 "chunking" 的方式实际上比初始代码消耗更多的内存。
您正在做的是立即获取所有记录,将它们存储在$recipes
中,然后通过调用chunk()
on the resulted collection 对结果进行分块。
相反,您需要在底层 Recipe
模型的查询构建器上调用具有相同名称 chunk()
的方法,并逐块生成哈希值:
Recipe::chunk(1000, function ($recipies) {
// Hash generation logic here
});
这样,您就可以消除巨大的 $recipes
变量,我确信这是这里的瓶颈。根据可用内存,您可能需要稍微调整块大小以避免内存耗尽。
此外,我会尝试在生成哈希时使用较少的变量,而不是留下 $extras1Total
、extras2Total
、...变量的踪迹。所有这些都可以用一个 $total
替换,它将被一遍又一遍地重写。不过这是微优化。
P.S。如果数据库写入压力很大(这在总共 28k 的情况下很少见),您可能需要考虑一次(或几次)执行最终更新,而不是每条记录执行一次。
我正在编写一个 artisan 控制台命令,循环遍历 table 中的所有记录并在 table 上重新生成一个字段。
该字段是一个 hash
并作为特定字符串的 md5()
生成。
最初我的代码是这样的:
// Get all recipes
$recipes = Recipe::all();
$hashProgress = $this->output->createProgressBar(count($recipes));
// Loop over each recipe and generate a new hash for it
foreach ($recipes as $recipe)
{
$hashString = '';
$hashString .= $recipe->field1;
$hashString .= $recipe->field2;
$hashString .= $recipe->field3;
$hashString .= $recipe->field4;
$hashString .= $recipe->field5;
$hashString .= $recipe->field6;
$hashString .= $recipe->field7;
$extras1Total = $recipe->extras1->sum('amount');
$hashString .= $recipe->extras1->reduce(function ($str, $item) use ($extras1Total) {
return $str . $item->name . ($extras1Total == 0 ? $item->amount : ($item->amount / $extras1Total * 100));
}, '');
$extras2Total = $recipe->extras2->sum('amount');
$hashString .= $recipe->extras2->reduce(function ($str, $item) use ($extras2Total) {
return $str . $item->name . ($extras2Total == 0 ? $item->amount : ($item->amount / $extras2Total * 100));
}, '');
$extras3Total = $recipe->extras3->sum('amount');
$hashString .= $recipe->extras3->reduce(function ($str, $item) use ($extras3Total) {
return $str . $item->name . ($extras3Total == 0 ? $item->amount : ($item->amount / $extras3Total * 100));
}, '');
$extras4Total = $recipe->extras4->sum('amount');
$hashString .= $recipe->extras4->reduce(function ($str, $item) use ($extras4Total) {
return $str . $item->name . ($extras4Total == 0 ? $item->amount : ($item->amount / $extras4Total * 100));
}, '');
$recipe->update([
'hash' => md5($hashString),
]);
$hashProgress->advance();
}
$hashProgress->finish();
$this->info(' Recipe hashes regenerated.');
在达到 28,000 条记录中的大约 10,000 条后,它将因内存耗尽错误而死掉:
PHP Fatal error: Allowed memory size of 268435456 bytes exhausted (tried to allocate 4096 bytes)
我认为 chunk
这样做可能会有帮助:
// Get all recipes
$recipes = Recipe::all();
$hashProgress = $this->output->createProgressBar(count($recipes));
// Loop over each recipe and generate a new hash for it
foreach ($recipes->chunk(1000) as $chunk)
{
foreach ($chunk as $recipe)
{
$hashString = '';
$hashString .= $recipe->field1;
$hashString .= $recipe->field2;
$hashString .= $recipe->field3;
$hashString .= $recipe->field4;
$hashString .= $recipe->field5;
$hashString .= $recipe->field6;
$hashString .= $recipe->field7;
$extras1Total = $recipe->extras1->sum('amount');
$hashString .= $recipe->extras1->reduce(function ($str, $item) use ($extras1Total) {
return $str . $item->name . ($extras1Total == 0 ? $item->amount : ($item->amount / $extras1Total * 100));
}, '');
$extras2Total = $recipe->extras2->sum('amount');
$hashString .= $recipe->extras2->reduce(function ($str, $item) use ($extras2Total) {
return $str . $item->name . ($extras2Total == 0 ? $item->amount : ($item->amount / $extras2Total * 100));
}, '');
$extras3Total = $recipe->extras3->sum('amount');
$hashString .= $recipe->extras3->reduce(function ($str, $item) use ($extras3Total) {
return $str . $item->name . ($extras3Total == 0 ? $item->amount : ($item->amount / $extras3Total * 100));
}, '');
$extras4Total = $recipe->extras4->sum('amount');
$hashString .= $recipe->extras4->reduce(function ($str, $item) use ($extras4Total) {
return $str . $item->name . ($extras4Total == 0 ? $item->amount : ($item->amount / $extras4Total * 100));
}, '');
$recipe->update([
'hash' => md5($hashString),
]);
$hashProgress->advance();
}
}
$hashProgress->finish();
$this->info(' Recipe hashes regenerated.');
但我仍然遇到内存耗尽错误。
如何在不增加内存限制的情况下遍历所有这些记录并实现我所追求的目标?
您 "chunking" 的方式实际上比初始代码消耗更多的内存。
您正在做的是立即获取所有记录,将它们存储在$recipes
中,然后通过调用chunk()
on the resulted collection 对结果进行分块。
相反,您需要在底层 Recipe
模型的查询构建器上调用具有相同名称 chunk()
的方法,并逐块生成哈希值:
Recipe::chunk(1000, function ($recipies) {
// Hash generation logic here
});
这样,您就可以消除巨大的 $recipes
变量,我确信这是这里的瓶颈。根据可用内存,您可能需要稍微调整块大小以避免内存耗尽。
此外,我会尝试在生成哈希时使用较少的变量,而不是留下 $extras1Total
、extras2Total
、...变量的踪迹。所有这些都可以用一个 $total
替换,它将被一遍又一遍地重写。不过这是微优化。
P.S。如果数据库写入压力很大(这在总共 28k 的情况下很少见),您可能需要考虑一次(或几次)执行最终更新,而不是每条记录执行一次。