Put column family information in LiveFileMetaData

Summary: As summary

Test Plan: compiles :)

Reviewers: dhruba, haobo, sdong, yhchiang

Reviewed By: haobo

CC: leveldb

Differential Revision: https://reviews.facebook.net/D18405

db/version_set.cc

@@ -2742,6 +2742,7 @@ void VersionSet::GetLiveFilesMetaData(std::vector<LiveFileMetaData>* metadata) {
     for (int level = 0; level < cfd->NumberLevels(); level++) {
       for (const auto& file : cfd->current()->files_[level]) {
         LiveFileMetaData filemetadata;
+        filemetadata.column_family_name = cfd->GetName();
         filemetadata.name = TableFileName("", file->number);
         filemetadata.level = level;
         filemetadata.size = file->file_size;

include/rocksdb/db.h

@@ -54,6 +54,7 @@ class Env;
 
 // Metadata associated with each SST file.
 struct LiveFileMetaData {
+  std::string column_family_name;  // Name of the column family
   std::string name;                // Name of the file
   int level;               // Level at which this file resides.
   size_t size;             // File size in bytes.