a7b2bedfb0
Introduce new tags for records that have a log_number. This changes the header size from 7 to 11 for these records, making this a backward-incompatible change. If we read a record that belongs to a different log_number (i.e., a previous instantiation of this log file, before it was most recently recycled), we return kOldRecord from ReadPhysicalRecord. ReadRecord will translate this into a kEof or kBadRecord depending on what the WAL recovery mode is. We make several adjustments to the log_test.cc tests to compensate for the fact that the header size varies between the two modes. Signed-off-by: Sage Weil <sage@redhat.com>
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/