# Memory usage of empty predicates

**URL:** <https://discuss.dgraph.io/t/memory-usage-of-empty-predicates/9910>\
**Category:** Dgraph\
**Tags:** dgraph, help-wanted\
**Created:** [August 30, 2020, 11:33pm UTC](https://discuss.dgraph.io/t/memory-usage-of-empty-predicates/9910 "2020-08-30T23:33:02Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![gorillastanley](https://yyz1.discourse-cdn.com/flex007/user_avatar/discuss.dgraph.io/gorillastanley/32/4518_2.png) [@gorillastanley](https://discuss.dgraph.io/u/gorillastanley)\
**Post date:** [August 30, 2020, 11:33pm UTC](https://discuss.dgraph.io/t/memory-usage-of-empty-predicates/9910/1 "2020-08-30T23:33:02Z")

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Do empty predicates take up much memory?  
If I have:

```auto
type LinkObject {
    ...
	skillsLink: String
	notesLink: String
	attachmentsLink: String
	videosLink: String
	floatsLink: String
	submissionsLink: String
	applicationsLink: String
	placementsLink: String
}

```

and say the above predicates are never used, will this have a significantly bad effect on memory used, or will they only take up a lot of memory once the predicate’s value is defined?

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**Author:** ![MichelDiz](https://yyz1.discourse-cdn.com/flex007/user_avatar/discuss.dgraph.io/micheldiz/32/11873_2.png) [@MichelDiz](https://discuss.dgraph.io/u/MichelDiz)\
**Post date:** [August 31, 2020, 4:40am UTC](https://discuss.dgraph.io/t/memory-usage-of-empty-predicates/9910/2 "2020-08-31T04:40:22Z")

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> [@gorillastanley](#):
>
> they only take up a lot of memory once the predicate’s value is defined

The second one. If the predicate doesn’t exist, if you mutate with “null” (which Dgraph doesn’t supports) it will be empty. And if it is empty, the query system will ignore it. So nothing will go to memory at all.

But I’m a bit confused (not much) about what you mean by “memory”. Do you mean storage or RAM? I see that sometimes people use “memory” as a synonym of storage.

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<div class="post-metadata">

**Author:** ![gorillastanley](https://yyz1.discourse-cdn.com/flex007/user_avatar/discuss.dgraph.io/gorillastanley/32/4518_2.png) [@gorillastanley](https://discuss.dgraph.io/u/gorillastanley)\
**Post date:** [August 31, 2020, 4:43am UTC](https://discuss.dgraph.io/t/memory-usage-of-empty-predicates/9910/3 "2020-08-31T04:43:22Z")

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Thanks! By memory I meant storage, yes. Or whatever stores all the nodes and stuff 🙂

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<div class="post-metadata">

**Author:** ![MichelDiz](https://yyz1.discourse-cdn.com/flex007/user_avatar/discuss.dgraph.io/micheldiz/32/11873_2.png) [@MichelDiz](https://discuss.dgraph.io/u/MichelDiz)\
**Post date:** [August 31, 2020, 4:44am UTC](https://discuss.dgraph.io/t/memory-usage-of-empty-predicates/9910/4 "2020-08-31T04:44:43Z")

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Okay, I have assumed it was RAM hehehe, but neither one will be used.