81229b8f39
Added an optional SequenceNumber hint to WAL manager's GetSortedWalFiles API. This allows GetSortedWalFiles to prune irrelevant files early. It will use the sequence number cache for this. This requires a scan over the sequence number cache, which will take time proportional to the number of entries in the cache. However, it may still be a lot better than peeking into the WAL files and performing lots of IO. The change helps when there are many (archived) WAL files and the first call to GetUpdatesSince() with a sequence number close to the tip of the WAL. Previously, this would open _all_ available WAL files and read their first entries to find out the lowest sequence number per file. With the change, we now keep track of the lowest sequence number as we open files, so that we can ignore all WAL files with a log number that is lower than the log number we will need. Note that the sequence number given to GetSortedWalFiles is only a hint, which is used as a performance optimization. The API can still return more files than needed, so that callers may still want to post-filter its result (GetUpdatesSince does so). But in the ideal case the hint allows performing less file IOs or at least building up smaller in-memory results. |
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| DEFAULT_OPTIONS_HISTORY.md | ||
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| LANGUAGE-BINDINGS.md | ||
| LICENSE.Apache | ||
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| README.md | ||
| ROCKSDB_LITE.md | ||
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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.