db325a5904
Summary: Logically, subcompactions process a key range [start, end); however, the way this is currently implemented is that the `CompactionIterator` for any given subcompaction keeps processing key-values until it actually outputs a key that is out of range, which is then discarded. Instead of doing this, the patch introduces a new type of internal iterator called `ClippingIterator` which wraps another internal iterator and "clips" its range of key-values so that any KVs returned are strictly in the [start, end) interval. This does eliminate a (minor) inefficiency by stopping processing in subcompactions exactly at the limit; however, the main motivation is related to BlobDB: namely, we need this to be able to measure the amount of garbage generated by a subcompaction precisely and prevent off-by-one errors. Pull Request resolved: https://github.com/facebook/rocksdb/pull/8327 Test Plan: `make check` Reviewed By: siying Differential Revision: D28761541 Pulled By: ltamasi fbshipit-source-id: ee0e7229f04edabbc7bed5adb51771fbdc287f69
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 especially 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/ and https://rocksdb.slack.com/
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.