601b1aaca0
Summary: In D43239 (https://reviews.facebook.net/D43239) there is an assertion to make sure a subcompaction's output is never empty at the end of execution. This assertion however breaks the build because some tests lead to exactly that scenario. So instead I have altered the logic to handle this case instead of just failing the assertion. The reason that it is possible for a subcompaction's output to be empty is that during a sequential execution of subcompactions, if a user aborts the compaction job then some of the later subcompactions to be executed may have yet to process any keys and therefore have yet to generate output files. This becomes very rare once the subcompactions are executed in parallel, but for now they are still sequential so the case is possible when there is an early termination, as in some of the tests. Test Plan: ./db_test ./db_compaction_test Reviewers: sdong, igor, anthony, yhchiang Reviewed By: yhchiang Subscribers: dhruba Differential Revision: https://reviews.facebook.net/D44877
RocksDB: A Persistent Key-Value Store for Flash and RAM Storage
RocksDB is developed and maintained by Facebook Database Engineering Team. It is built on earlier work on LevelDB by Sanjay Ghemawat (sanjay@google.com) and Jeff Dean (jeff@google.com)
This code is a library that forms the core building block for a fast key value server, especially suited for storing data on flash drives. It has a Log-Structured-Merge-Database (LSM) design with flexible tradeoffs between Write-Amplification-Factor (WAF), Read-Amplification-Factor (RAF) and Space-Amplification-Factor (SAF). It has multi-threaded compactions, making it specially suitable for storing multiple terabytes of data in a single database.
Start with example usage here: https://github.com/facebook/rocksdb/tree/master/examples
See the github wiki for more explanation.
The public interface is in include/. Callers should not include or
rely on the details of any other header files in this package. Those
internal APIs may be changed without warning.
Design discussions are conducted in https://www.facebook.com/groups/rocksdb.dev/