e1ea04d9ef
Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/14876 Add reverse scan support to `MultiScanArgs`/`MultiScan` so callers can iterate bounded scan ranges in descending order. Plumb reverse scan state through `DBIter`, `BlockBasedTableIterator`, and `MultiScanIndexIterator`, including reverse prefetch windowing and async I/O support. Update `db_bench` `multiscanrandom` to honor `--reverse_iterator` and report rows scanned so reverse MultiScan and iterator baselines can be compared on row throughput. Add `db_stress --multiscan_reverse` coverage so the prepared MultiScan path can be stressed with `SeekForPrev()`/`Prev()` against a control iterator. Also fix the table child iterator path to accept reverse `SeekForPrev()` targets above a file's prepared ranges. `MergingIterator` and `LevelIterator` can legally seek every child to the current range limit; a child file may only have lower prepared ranges, so treating that as invalid caused intermittent `SeekForPrev target is outside prepared ranges` exceptions in the benchmark. Reviewed By: xingbowang Differential Revision: D109357730 fbshipit-source-id: eccece5ca7d8f5d6760d51ebe76801a332a49061
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.