Proposed changes in NFS

Core Libraries Client Libs
14

No, not with the current structure - because DataMap, size, modified time stamp etc (the things that changes when contents change) are all part of metadata stored with parent folder. It is for performance reason. If there are 100 files in a dir you dont have to do 100 gets to retrieve the metadata. So you can only modify files in different dirs simultaneously.

However if this is like a the feature that would be greatly missed if absent then what we can do is change:

struct FileMetadata {
    name: String,
    size: u64,
    created: Time,
    modified: Time,
    user_metadata: Vec<u8>,
    data_map: DataMap,
}

to

struct FileMetadata {
    name: String,
    created: Time,
    user_metadata: Vec<u8>,
    further_info: DataIdentifier, // Points to SD::data(FurtherInfo)
}

struct FurtherInfo {
    modified: Time,
    size: u64,
    data_map: DataMap,
}

That way, only the relatively unchanging parts remain in metadata stored with parent. Others are offloaded via pointer to elsewhere.

Now you can edit and post contents of files in same folder simultaneously too at a slight overhead of indirection and hence performance. However you won’t be able to post the changes in name or user-metadata for files in same folder simultaneiously (should be done serially). To do that you will need to offload the whole metadata to some location, but this will have significant performance impact. If a dir had 100 files, previously you could display all of them at one go on entering it (because name and user-metadata {for and special icons etc}) was all there. Now you would need to make 100 gets for merely that. And then separate ones for contents of each. So there will be a trade off.

What do you think about this ^^^ ?

That depends on the app - anything striving for performance should be well aware of it’s environment though. Launcher cannot know what the app wants - if it wants a bulk update or immediate post or something else etc. But we can discuss if you give more details on what kind of app you have in mind and what are your expectation from the backend for it.

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