Set correct temperature for range tombstone only file in penultimate level (#10972)

Summary:
before this PR, if there is a range tombstone-only file generated in penultimate level, it is marked the `last_level_temperature`. This PR fixes this issue.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10972

Test Plan: added unit test for this scenario.

Reviewed By: ajkr

Differential Revision: D41449215

Pulled By: cbi42

fbshipit-source-id: 1e06b5ae3bc0183db2991a45965a9807a7e8be0c

db/compaction/subcompaction_state.h

@@ -196,8 +196,11 @@ class SubcompactionState {
                               const CompactionFileCloseFunc& close_file_func) {
     // Call FinishCompactionOutputFile() even if status is not ok: it needs to
     // close the output file.
+    // CloseOutput() may open new compaction output files.
+    is_current_penultimate_level_ = true;
     Status s = penultimate_level_outputs_.CloseOutput(
         curr_status, open_file_func, close_file_func);
+    is_current_penultimate_level_ = false;
     s = compaction_outputs_.CloseOutput(s, open_file_func, close_file_func);
     return s;
   }

db/compaction/tiered_compaction_test.cc

@@ -663,8 +663,19 @@ TEST_P(TieredCompactionTest, LevelOutofBoundaryRangeDelete) {
   cro.bottommost_level_compaction = BottommostLevelCompaction::kForce;
   ASSERT_OK(db_->CompactRange(cro, nullptr, nullptr));
 
-  ASSERT_EQ(GetSstSizeHelper(Temperature::kUnknown),
-            0);  // tombstone has no size, even it's in hot tier
+  // range tombstone is not in cold tier
+  ASSERT_GT(GetSstSizeHelper(Temperature::kUnknown), 0);
+  std::vector<std::vector<FileMetaData>> level_to_files;
+  dbfull()->TEST_GetFilesMetaData(dbfull()->DefaultColumnFamily(),
+                                  &level_to_files);
+  // range tombstone is in the penultimate level
+  const int penultimate_level = kNumLevels - 2;
+  ASSERT_EQ(level_to_files[penultimate_level].size(), 1);
+  ASSERT_EQ(level_to_files[penultimate_level][0].num_entries, 1);
+  ASSERT_EQ(level_to_files[penultimate_level][0].num_deletions, 1);
+  ASSERT_EQ(level_to_files[penultimate_level][0].temperature,
+            Temperature::kUnknown);
+
   ASSERT_GT(GetSstSizeHelper(Temperature::kCold), 0);
   ASSERT_EQ("0,1,10",
             FilesPerLevel());  // one file is at the penultimate level which