Storage engine differences

[Simran-B]

There are some remarks here and there which do not distinguish between MMFiles and RocksDB, e.g.

`collection.figures()`

Returns an object containing statistics about the collection.

{% hint 'info' %}
Retrieving the figures will always load the collection into memory.
{% endhint %}

Does RocksDB load the collection metadata only, and does it so on first use or is it always in memory?

[Simran-B]

Related:

`collection.load()`

Loads a collection into memory.

{% hint 'info' %}
Cluster collections are loaded at all times.
{% endhint %}

#84 #35

[dothebart]

'Loading collections' in MMFiles includes building up indices in RAM, which may take time depending on the collection size and the index complexity.
For rocksdb we don't do this.