com.twitter.summingbird.scalding.store
Returns a VersionedBatchStore that tags the BatchID alongside the stored value.
Returns a VersionedBatchStore that tags the BatchID alongside the stored value. This is required to serve data through a read-only key-value store designed to serve values in tandem with a realtime layer (that stores (K, BatchID) -> V)).
The packing function receives the inclusive upper BatchID being committed. We actually need to store the exclusive upper bound alongside the value, so the packing function calls batchID.next. On the unpack, we drop the batchID, so no off-by-one error arises.
See summingbird-client's ClientStore for more information on the merge between offline and online data.
Scalding implementation of the batch read and write components of a store that uses the VersionedKeyValSource from scalding-commons.