b923dc720b
Summary: BackupEngine requires computing table checksums twice when backing up table files to the `shared_checksum` directory. The repeated computation can be avoided by utilizing the db session id stored as a part of the table properties. Filenames of table files in the `shared_checksum` directory depend on the following conditions: 1. the naming scheme is `kOptionalChecksumAndDbSessionId`, 2. `db_session_id` is not empty, 3. checksum is available in the DB manifest. If 1,2,3 are satisfied, then the filenames will be of the form `<file_number>_<checksum>_<db_session_id>.sst`. If 1,2 are satisfied, then the filenames will be of the form `<file_number>_<db_session_id>.sst`. In all other cases, the filenames are of the form `<file_number>_<checksum>_<size>.sst`. Additionally, if `kOptionalChecksumAndDbSessionId` is used (and not falling back to `kChecksumAndFileSize`), the `<checksum>` appeared in the filenames is hexadecimally encoded, instead of being plain `uint32_t` value. Pull Request resolved: https://github.com/facebook/rocksdb/pull/7110 Test Plan: backupable_db_test and manual tests. Reviewed By: ajkr Differential Revision: D22508992 Pulled By: gg814 fbshipit-source-id: 5669f0ea9ad5a097f69f6d87aca4abba15032389
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/master/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.
Design discussions are conducted in https://www.facebook.com/groups/rocksdb.dev/ and https://rocksdb.slack.com/
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.