For some read-only files, the mmap can be used to improve the reading performance in read-only situation a lot. For example, when doing major compaction, reading the input SSTables by mmap may be more sufficient than just calling read().
In origin leveldb fs layer env, PosixMmapReadableFile is introduced for such cases.
For some read-only files, the
mmapcan be used to improve the reading performance in read-only situation a lot. For example, when doing major compaction, reading the input SSTables bymmapmay be more sufficient than just callingread().In origin
leveldbfs layerenv,PosixMmapReadableFileis introduced for such cases.