Resulting document after update is larger than 16777216

[dev-erem]

• Laravel-mongodb Version: 3.4
• PHP Version: 7.2.x.
• Database Driver & Version: 4.2

On saving many-to-many relation, my lumen app returns following error
Resulting document after update is larger than 16777216

[Smolevich]

Looks like as mongo database error

[dev-erem]

@Smolevich , yes this is mongo database error. There is a many-to-many relationship between categories & posts, and attach operation adds references to both documents. now one document i.e. category has reached max limit of 16MB, so this error occurred. Any work around?

[Smolevich]

You can describe example of data and write actual mongo driver version

[dev-erem]

@Smolevich
This is what i get after running command on terminal php --ri mongodb | grep version
MongoDB extension version => 1.7.2
libbson bundled version => 1.16.1
libmongoc bundled version => 1.16.1
libmongocrypt bundled version => 1.0.3

[dev-erem]

Example Category document as under:

{
	_id: ObjectId("5ede5420e6fc8c04841cc212"),
	name: "sports",
	post_ids:[
	    "5e92a31749cad1b17b430822",
	    "5e92a31749cad1b17b430823",
	    "5e92a31749cad1b17b430824",
	    ....
	    ....
	    ....
	    "5e92a31749cad1b17b430822",
	    "5ec130981c51930cbd188fe2"
	]
}

Example Post document as under:

{
	"_id": "ObjectId("5e92a31f49cad1b17b4a1dee"),
	"title": "A sports related news",
	"summary": "Lorem epsum ....",	
	"category_ids": [
		"5e92a31b49cad1b17b45b35f", 
        	"5e92a31b49cad1b17b45b4e0"
	]
}

[dev-erem]

Now sports category has around 460000 post_ids, and creating a new relation b/w any new post with sports category generate this bug.

[divine]

This has nothing to do with the library.

The document size can't exceed 16MB. Change your logic, it's mongodb overall (you're not forced to do some hard sql relations)

I don't see a reason why you're referring post_ids in Category document? Doesn't make sense at all.

[dev-erem]

Hi @divine ,

I am not referring post_ids in Category document explicitly. I am using following code in my controller to relate a post with a category object:
$category->posts()->attach($post);

[divine]

@amjad-eremnews well, I don't remember exactly but probably that's the problem.

In normal laravel mysql/postresql relations attach does use special table to store those references.

In this library mongodb it does work a little bit different, it actually saves in one document.

What I could suggest to solve this problem? Probably referencing attached categories only on posts documents might solve the problem.

Thanks.

[dev-erem]

@divine

I don't think referencing attached categories only on posts documents will the solve the problem. can you check line number 203 on https://github.com/jenssegers/laravel-mongodb/blob/master/src/Jenssegers/Mongodb/Relations/BelongsToMany.php. ?

[divine]

@amjad-eremnews you're right, then the solution would be this:

// Add new category to post
$post->push('category_ids',  $category_id, true);

// Remove category from post
$post->pull('category_ids', $category_id);

This way your main category document wouldn't filled up. However, you'll need probably adjust your relations but this is probably only workaround that is possible currently.

Let me know, if you'll have any more questions.

Thanks.

[dev-erem]

yes i have already applied this for now.