21723bbbef
Summary: - Add experimental immutable `DBOptions::async_wal_precreate` to reserve and open one future WAL on a background HIGH-priority task, with sanitization that disables the optimization when WAL recycling is configured. - Split WAL creation into open/preallocate and start phases so `SwitchMemtable()` can consume a prepared WAL after writing normal WAL metadata, wait for in-flight precreation, fall back to synchronous creation, and delete an unstarted prepared WAL on start failure. - Keep WAL numbering, close, recovery, and read-only open safe for empty future WAL files left by async precreation; `error_if_wal_file_exists=true` now rejects non-empty WALs while tolerating empty WALs. - Add public option plumbing for the C API, options parsing/stringification, random option testing, `db_bench`, `db_stress`, and crash-test configuration. - Add WAL precreate statistics counters plus Java `TickerType`/JNI mappings, and update C++, C, and Java read-only-open documentation for the empty-WAL behavior. - Add focused WAL/option/C/Java tests for async precreate ready/wait/failure/recovery paths, read-only WAL detection, option sanitization, and API plumbing, plus write-flow docs and unreleased history entries for the new feature and behavior change. PR https://github.com/facebook/rocksdb/pull/14738 Reviewed By: pdillinger Differential Revision: D105020559 fbshipit-source-id: 5059b424702e021abb8de65ceeb6d3b975280ffc
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.