bcfc53b436
Summary: As the code changes for block cache tracing are almost complete, I did a benchmark to compare the performance when block cache tracing is enabled/disabled. With 1% downsampling ratio, the performance overhead of block cache tracing is negligible. When we trace all block accesses, the throughput drops by 6 folds with 16 threads issuing random reads and all reads are served in block cache. Setup: RocksDB: version 6.2 Date: Mon Jun 17 17:11:13 2019 CPU: 24 * Intel Core Processor (Skylake) CPUCache: 16384 KB Keys: 20 bytes each Values: 100 bytes each (100 bytes after compression) Entries: 10000000 Prefix: 20 bytes Keys per prefix: 0 RawSize: 1144.4 MB (estimated) FileSize: 1144.4 MB (estimated) Write rate: 0 bytes/second Read rate: 0 ops/second Compression: NoCompression Compression sampling rate: 0 Memtablerep: skip_list Perf Level: 1 I ran the readrandom workload for 1 minute. Detailed throughput results: (ops/second) Sample rate 0: no block cache tracing. Sample rate 1: trace all block accesses. Sample rate 100: trace accesses 1% blocks. 1 thread | | | -- | -- | -- | -- Sample rate | 0 | 1 | 100 1 MB block cache size | 13,094 | 13,166 | 13,341 10 GB block cache size | 202,243 | 188,677 | 229,182 16 threads | | | -- | -- | -- | -- Sample rate | 0 | 1 | 100 1 MB block cache size | 208,761 | 178,700 | 201,872 10 GB block cache size | 2,645,996 | 426,295 | 2,587,605 Pull Request resolved: https://github.com/facebook/rocksdb/pull/5473 Differential Revision: D15869479 Pulled By: HaoyuHuang fbshipit-source-id: 7ae802abe84811281a6af8649f489887cd7c4618
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.