a736255de8
Summary: This is still WIP, but I'm hoping for early feedback on the overall approach. This patch implements deletion triggered compaction, which till now only worked for leveled, for universal style. SST files are marked for compaction by the CompactOnDeletionCollertor table property. This is expected to be used when free disk space is low and the user wants to reclaim space by deleting a bunch of keys. The deletions are expected to be dense. In such a situation, we want to avoid a full compaction due to its space overhead. The strategy used in this case is similar to leveled. We pick one file from the set of files marked for compaction. We then expand the inputs to a clean cut on the same level, and then pick overlapping files from the next non-mepty level. Picking files from the next level can cause the key range to expand, and we opportunistically expand inputs in the source level to include files wholly in this key range. The main side effect of this is that it breaks the property of no time range overlap between levels. This shouldn't break any functionality. Closes https://github.com/facebook/rocksdb/pull/3860 Differential Revision: D8124397 Pulled By: anand1976 fbshipit-source-id: bfa2a9dd6817930e991b35d3a8e7e61304ed3dcf
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/
License
RocksDB is dual-licensed under both the GPLv2 (found in the COPYING file in the root directory) and Apache 2.0 License (found in the LICENSE.Apache file in the root directory). You may select, at your option, one of the above-listed licenses.