logging_when_create_and_delete_manifest

Summary:
  1. logging when create and delete manifest file
  2. fix formating in table/format.cc

Test Plan:
  make all check
  run db_bench, track the LOG file.

Reviewers: ljin, yhchiang, igor, yufei.zhu, sdong

Reviewed By: sdong

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D21009

db/db_impl.cc

@@ -450,6 +450,7 @@ Status DBImpl::NewDB() {
   new_db.SetNextFile(2);
   new_db.SetLastSequence(0);
 
+  Log(options_.info_log, "Creating manifest 1 \n");
   const std::string manifest = DescriptorFileName(dbname_, 1);
   unique_ptr<WritableFile> file;
   Status s = env_->NewWritableFile(

db/version_set.cc

@@ -1881,6 +1881,9 @@ Status VersionSet::LogAndApply(ColumnFamilyData* column_family_data,
     // This is fine because everything inside of this block is serialized --
     // only one thread can be here at the same time
     if (new_descriptor_log) {
+      // create manifest file
+      Log(options_->info_log,
+          "Creating manifest %" PRIu64 "\n", pending_manifest_file_number_);
       unique_ptr<WritableFile> descriptor_file;
       s = env_->NewWritableFile(
           DescriptorFileName(dbname_, pending_manifest_file_number_),
@@ -2002,6 +2005,9 @@ Status VersionSet::LogAndApply(ColumnFamilyData* column_family_data,
         column_family_data->GetName().c_str());
     delete v;
     if (new_descriptor_log) {
+      Log(options_->info_log,
+        "Deleting manifest %" PRIu64 " current manifest %" PRIu64 "\n",
+        manifest_file_number_, pending_manifest_file_number_);
       descriptor_log_.reset();
       env_->DeleteFile(
           DescriptorFileName(dbname_, pending_manifest_file_number_));

table/format.cc

@@ -208,9 +208,8 @@ Status ReadFooterFromFile(RandomAccessFile* file,
 // contents is the result of reading.
 // According to the implementation of file->Read, contents may not point to buf
 Status ReadBlock(RandomAccessFile* file, const Footer& footer,
-                       const ReadOptions& options, const BlockHandle& handle,
-                       Slice* contents,  // result of reading,
-                       char* buf) {
+                  const ReadOptions& options, const BlockHandle& handle,
+                  Slice* contents,  /* result of reading */ char* buf) {
   size_t n = static_cast<size_t>(handle.size());
 
   PERF_TIMER_AUTO(block_read_time);
@@ -256,8 +255,8 @@ Status ReadBlock(RandomAccessFile* file, const Footer& footer,
 // Decompress a block according to params
 // May need to malloc a space for cache usage
 Status DecompressBlock(BlockContents* result, size_t block_size,
-                             bool do_uncompress, const char* buf,
-                             const Slice& contents, bool use_stack_buf) {
+                          bool do_uncompress, const char* buf,
+                          const Slice& contents, bool use_stack_buf) {
   Status s;
   size_t n = block_size;
   const char* data = contents.data();