|
Hi xianzhuo.sky@gmail.com Time series collections behave different from regular collections when it comes to the primary key index. The primary key index of a Time Series collection is an automatically created clustered index on a server generated unique _id value for a group of documents with a unique metaField for a time span. This index and value can be seen in the corresponding system.buckets.foo collection for your Time Series collection, but is more for internal usage, e.g. the TTL index if enabled.
The _id of the document cannot currently be indexed and cannot be the primary key index for a Time Series collection like a regular collection. That being said, we are currently working on allowing secondary index creation on the _id field for Time Series collections so that you may still create an index on the _id of the document if needed
|