f5ee207c64
Summary: Background activities like compaction can negatively affect latency of higher-priority tasks like request processing. To avoid this, rocksdb already lowers the IO priority of background threads on Linux systems. While this takes care of typical IO-bound systems, it does not help much when CPU (temporarily) becomes the bottleneck. This is especially likely when using more expensive compression settings. This patch adds an API to allow for lowering the CPU priority of background threads, modeled on the IO priority API. Benchmarks (see below) show significant latency and throughput improvements when CPU bound. As a result, workloads with some CPU usage bursts should benefit from lower latencies at a given utilization, or should be able to push utilization higher at a given request latency target. A useful side effect is that compaction CPU usage is now easily visible in common tools, allowing for an easier estimation of the contribution of compaction vs. request processing threads. As with IO priority, the implementation is limited to Linux, degrading to a no-op on other systems. Closes https://github.com/facebook/rocksdb/pull/3763 Differential Revision: D7740096 Pulled By: gwicke fbshipit-source-id: e5d32373e8dc403a7b0c2227023f9ce4f22b413c
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.