d66bb21e18
Summary: Adding the `min_blob_size` option to allow storing small values in base db (in LSM tree) together with the key. The goal is to improve performance for small values, while taking advantage of blob db's low write amplification for large values. Also adding expiration timestamp to blob index. It will be useful to evict stale blob indexes in base db by adding a compaction filter. I'll work on the compaction filter in future patches. See blob_index.h for the new blob index format. There are 4 cases when writing a new key: * small value w/o TTL: put in base db as normal value (i.e. ValueType::kTypeValue) * small value w/ TTL: put (type, expiration, value) to base db. * large value w/o TTL: write value to blob log and put (type, file, offset, size, compression) to base db. * large value w/TTL: write value to blob log and put (type, expiration, file, offset, size, compression) to base db. Closes https://github.com/facebook/rocksdb/pull/3066 Differential Revision: D6142115 Pulled By: yiwu-arbug fbshipit-source-id: 9526e76e19f0839310a3f5f2a43772a4ad182cd0
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/