Avoid retrying to read property block from a table when it does not exist.

Summary:
Avoid retrying to read property block from a table when it does not exist
in updating stats for compensating deletion entries.

In addition, ReadTableProperties() now returns Status::NotFound instead
of Status::Corruption when table properties does not exist in the file.

Test Plan:
make db_test -j32
export ROCKSDB_TESTS=CompactionDeleteionTrigger
./db_test

Reviewers: ljin, sdong

Reviewed By: sdong

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D21867

Author: yhchiang

db/version_edit.h

@@ -81,6 +81,8 @@ struct FileMetaData {
   uint64_t num_deletions;          // the number of deletion entries.
   uint64_t raw_key_size;           // total uncompressed key size.
   uint64_t raw_value_size;         // total uncompressed value size.
+  bool init_stats_from_file;   // true if the data-entry stats of this file
+                               // has initialized from file.
 
   FileMetaData()
       : refs(0),
@@ -90,7 +92,8 @@ struct FileMetaData {
         num_entries(0),
         num_deletions(0),
         raw_key_size(0),
-        raw_value_size(0) {}
+        raw_value_size(0),
+        init_stats_from_file(false) {}
 };
 
 // A compressed copy of file meta data that just contain

db/version_set.cc

@@ -879,12 +879,16 @@ void Version::PrepareApply(std::vector<uint64_t>& size_being_compacted) {
 }
 
 bool Version::MaybeInitializeFileMetaData(FileMetaData* file_meta) {
-  if (file_meta->num_entries > 0) {
+  if (file_meta->init_stats_from_file) {
     return false;
   }
   std::shared_ptr<const TableProperties> tp;
   Status s = GetTableProperties(&tp, file_meta);
+  file_meta->init_stats_from_file = true;
   if (!s.ok()) {
+    Log(vset_->options_->info_log,
+        "Unable to load table properties for file %" PRIu64 " --- %s\n",
+        file_meta->fd.GetNumber(), s.ToString().c_str());
     return false;
   }
   if (tp.get() == nullptr) return false;

table/meta_blocks.cc

@@ -253,8 +253,7 @@ Status ReadTableProperties(RandomAccessFile* file, uint64_t file_size,
     s = ReadProperties(meta_iter->value(), file, footer, env, info_log,
                        properties);
   } else {
-    s = Status::Corruption("Unable to read the property block.");
-    Log(WARN_LEVEL, info_log, "Cannot find Properties block from file.");
+    s = Status::NotFound();
   }
 
   return s;