eca1a114e0
Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/14926 This fixes a gap in the MultiScan prefetch waste accounting introduced by https://github.com/facebook/rocksdb/pull/14876. That change added reverse MultiScan support and introduced `unreleased_prefetch_blocks_` to track prefetched blocks still owned by the `ReadSet`, because reverse scans can prefetch a suffix of the collected block list and release blocks in non-prefix order. However, those unreleased prefetched blocks were only released during `MultiScanIndexIterator` destruction; they were not included in `MULTISCAN_PREFETCH_BLOCKS_WASTED`. As a result, scans that stopped before consuming all prefetched blocks underreported wasted prefetch blocks. This change counts unreleased prefetched blocks as wasted before destructor cleanup, while avoiding counting the currently positioned block as wasted when it has been reached. Reviewed By: xingbowang Differential Revision: D111531409 fbshipit-source-id: 5e605ce686037256bf6847ab7ca363c3f7701401
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/main/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.
Questions and discussions are welcome on the RocksDB Developers Public Facebook group and email list on Google Groups.
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.