eb65d673fe
Summary: WAL may be truncated to an incomplete record due to crash while writing the last record or corruption. In the former case, no hole will be produced since no ACK'd data was lost. In the latter case, a hole could be produced without this PR since we proceeded to recover the next WAL as if nothing happened. This PR changes the record reading code to always report a corruption for incomplete records in `kPointInTimeRecovery` mode, and the upper layer will only ignore them if the next WAL has consecutive seqnum (i.e., we are guaranteed no hole). While this solves the hole problem for the case of incomplete records, the possibility is still there if the WAL is corrupted by truncation to an exact record boundary. This PR also regresses how much data can be recovered when writes are mixed with/without `WriteOptions::disableWAL`, as then we can not distinguish between a seqnum gap caused by corruption and a seqnum gap caused by a `disableWAL` write. Pull Request resolved: https://github.com/facebook/rocksdb/pull/7701 Test Plan: Interestingly there already was a test for this case (`DBWALTestWithParams.kPointInTimeRecovery`); it just had a typo bug in the verification that prevented it from noticing holes in recovery. Reviewed By: anand1976 Differential Revision: D25111765 Pulled By: ajkr fbshipit-source-id: 5e330b13b1ee2b5be096cea9d0ff6075843e57b6
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.