This commit adds a basic read endpoint to pull data out of the database. In order to provide the basic functionality a few things were added:
* Time package with limited support for parsing Flux style durations
* API endpoint at /api/v2/read with query paramters of org_id, bucket_name, predicate, start, and stop
The start and stop query parameters only support relative durations.
The predicate parameter supports what is possible in the parse_predicate method and in the RocksDB implementation (only == comparisons on tags and AND or OR)
This commit adds iterators for iterating over series and batches of points for a read range request. The exact signature/structure of the iterators are likely to change when this is generalized for other data types and other storage backends (S3 & memory).
This commit updates the write_points method to use the bucket id and series id in the key for a stored point value.
It also updates the Database methods to be immutable borrows moving any mutable concerns into interior structures so it can be easily called from many threads.
This commit brings in a Roaring Bitmap implementation to keep postings lists of tag key/value pairs to the set of series ids that have those pairs. The croaring implementation was used becasue the Treemap was required for u64 support for series ids and it was serializable (unlike the other pure Rust roaring implementation).
This doesn't shard the postings lists based on size. It also doesn't implement the time/index levels.
The predicate matching currently only works for a simple key = "value" match.
This commit is the beginning of the RocksDB based index for series and their tag metadata.
I started to stub out different index levels but stopped short of implementing them.
There are a number of spots where I'm unwrapping return values that we may want to revisit later. For now I want to have the program panic if those things pop up.
This updates to build system to use Prost to build the protobuf objects.
It adds tests for creating, storing and loading bucket definitions.
The tests use an actual on disk RocksDB implementation to ensure that its tested all the way to persistence.