Eloquent optimizationIntermediate5 questions

Eloquent query performance

N+1 queries, counting, plucking and chunking: pick the option that does less work.

01This loop runs one query for the posts and then one more query per post. Which change fixes that?
```
$posts = Post::all();

foreach ($posts as $post) {
    echo $post->author->name;
}
```
aPost::with('author')->get()bPost::all()->fresh()cPost::query()->lazy()dPost::select('author')->get()
02You only need the number of posts a user has. Which line avoids loading every post into memory?
a$user->posts->count()b$user->posts()->count()ccount($user->posts)d$user->posts->all()
03You need a list of every user's email address and nothing else. Which is the most efficient?
aUser::all()->pluck('email')bUser::get()->map(fn ($user) => $user->email)cUser::pluck('email')dUser::all()->toArray()
04This job should deactivate every active user, but it skips some of them. What is the documented fix?
```
User::where('active', true)->chunk(100, function ($users) {
    foreach ($users as $user) {
        $user->update(['active' => false]);
    }
});
```
aIncrease the chunk size to 1000bUse chunkById() instead of chunk()cWrap the loop in a database transactiondCall $users->fresh() inside the callback
05After Post::withCount('comments')->get(), where is each post's number of comments?
a$post->comments->countb$post->count_commentsc$post->commentsCount()d$post->comments_count

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