3b97ee96c4
Summary: If `NeedToSeekImmutable()` returns false, `SeekInternal()` won't reset the contents of `immutable_min_heap_`. However, since it calls `UpdateCurrent()` unconditionally, if `current_` is one of immutable iterators (previously popped from `immutable_min_heap_`), `UpdateCurrent()` will overwrite it. As a result, if old `current_` in fact pointed to the smallest entry, forward iterator will skip some records. Fix implemented in this diff pushes `current_` back to `immutable_min_heap_` before calling `UpdateCurrent()`. Test Plan: New unit test (courtesy of @lovro): $ ROCKSDB_TESTS=TailingIteratorSeekToSame ./db_test Reviewers: igor, dhruba, haobo, ljin Reviewed By: ljin Subscribers: lovro, leveldb Differential Revision: https://reviews.facebook.net/D19653
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 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 specially 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/