fbd2dafc9f
Summary: Add the MultiGet API to allow prefetching. With file size of 1.5G, I configured it to have 0.9 hash ratio that can fill With 115M keys and result in 2 hash functions, the lookup QPS is ~4.9M/s vs. 3M/s for Get(). It is tricky to set the parameters right. Since files size is determined by power-of-two factor, that means # of keys is fixed in each file. With big file size (thus smaller # of files), we will have more chance to waste lot of space in the last file - lower space utilization as a result. Using smaller file size can improve the situation, but that harms lookup speed. Test Plan: db_bench Reviewers: yhchiang, sdong, igor Reviewed By: sdong Subscribers: leveldb Differential Revision: https://reviews.facebook.net/D23673
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/