d394a6bb48
Summary: This diff adds a new ticker stat, NUMBER_ITER_SKIP, to count the number of internal keys skipped during iteration. Keys can be skipped due to deletes, or lower sequence number, or higher sequence number than the one requested. Also, fix the issue when StatisticsData is naturally aligned on cacheline boundary, padding becomes a zero size array, which the Windows compiler doesn't like. So add a cacheline worth of padding in that case to keep it happy. We cannot conditionally add padding as gcc doesn't allow using sizeof in preprocessor directives. Closes https://github.com/facebook/rocksdb/pull/3177 Differential Revision: D6353897 Pulled By: anand1976 fbshipit-source-id: 441d5a09af9c4e22e7355242dfc0c7b27aa0a6c2
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 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/