b06ca5f860
getline on std::cin can be very inefficient when ldb is loading large values, with high CPU usage in libc _IO_(un)getc, this is because of the performance penalty that comes from synchronizing stdio and iostream buffers. See the reproducers and tests in #1133 . If an ifstream on /dev/stdin is used (when available) then using ldb to load large values can be much more efficient. I thought for ldb load, that this approach is preferable to using <cstdio> or std::ios_base::sync_with_stdio(false). I couldn't think of a use case where ldb load would need to support reading unbuffered input, an alternative approach would be to add support for passing --input_file=/dev/stdin. I have a CLA in place, thanks. The CI tests were failing at the time of https://github.com/facebook/rocksdb/pull/1156, so this change and PR will supersede it.
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/