36838bbf51
Summary: This is a preparation for supporting merge in `WBWIMemTable`. This PR updates the sequence number assignment method so that it allows efficient and simple assignment when there are multiple entries with the same user key. This can happen when the WBWI contains Merge operations. This assignment relies on tracking the number of updates issued for each key in each WBWI entry (`WriteBatchIndexEntry::update_count`). Some refactoring is done in WBWI to remove `last_entry_offset` as part of the WBWI state which I find it harder to use correctly. Pull Request resolved: https://github.com/facebook/rocksdb/pull/13400 Test Plan: updated unit tests to check that update count is tracked correctly and WBWIMemTable is assigning sequence number as expected. Reviewed By: pdillinger Differential Revision: D69666462 Pulled By: cbi42 fbshipit-source-id: 9b18291825017a67c4da3318e8a556aa2971326b
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.