Add stats information to bucket/collection/record.

[msathis]

Stats like no of documents, how much memory it holds etc will be useful.

[leplatrem]

👍

No there isn't, but it's a good idea.

Related #173

[Natim]

@msathis do you have an idea of how you would like to access this information?

You can already have the number of records in a particular collection doing a head request to it:

http HEAD https://kinto-ota.dev.mozaws.net/v1/buckets/blocklists/collections/certificates/records

ETag: "1450717104423"
Last-Modified: Mon, 21 Dec 2015 16:58:24 GMT
Total-Records: 10

[msathis]

@Natim
Right now
GET https://kinto-ota.dev.mozaws.net/v1/buckets/mybucket --auth="test:test"
returns data, permissions. Additionally it can return one more property "stats" as well.

The properties i would like to see in stats object

1. collections_count - (Applicable only for buckets)
2. records_count - Total records. Not sure whether we need it for bucket stats too.
3. storage_size - In bytes.
4. last_write or updated_at - timestamp of last write.
5. last_read - timestamp of last read. (Not sure about this).
6. created_at - created timestamp.

[msathis]

And the data property in the response contains only last_modified property. It can also return created_at timestamp as well.

[Natim]

Thank you for this it is really interesting 👍

[tarekziade]

last_read - timestamp of last read. (Not sure about this).

I don't think that one is easy to implement. When you have a stack with several nodes, you would need to have a complex implementation to be able to have that info. What is your use case for this info ?

[Natim]

The proposition is to add on collection a readonly stats parameter such as permissions and data which contains:

For buckets

{
    "collections_count": 5,
    "storage_size": "478"
}

For collections

{
    "records_count": "114",
    "storage_size": "83"
}

[tarekziade]

Here are the two items I suggest we add in the collection or bucket metadata (and not used for the signing)

1. items_count
2. storage_size - In bytes.

Those two fields will be useful to implement a quota feature among other things. I don't think it should be added as a plugin. It sounds like a core feature that can be added without having to deal with plugin indirections, in particular if we have to deal with conflict resolutions at some point.

If we reach the consensus on how those two fields are stored we can do what @leplatrem suggested:

• On create, sum the bytes, on delete subtracts, on update sum the difference between old/new.

@msathis What is the use case for the created_at field ?

[Natim]

It is already possible to get the last_write and we can use kinto-changes for that.
Also having the creation date can be achieve with the kinto-history plugin that let you have an full audit trail.

[leplatrem]

What's the status of this ? Does the built-in plugin kinto.plugins.quotas covers this already?

BTW created date was later reported in issue #679