Fix deletion counting in memtable stats (facebook#10886)

Summary:
Currently, a memtable's stats `num_deletes_` is incremented only if the entry is a regular delete (kTypeDeletion). We need to fix it by accounting for kTypeSingleDeletion and kTypeDeletionWithTimestamp.

Pull Request resolved: facebook#10886

Test Plan: make check

Reviewed By: ltamasi

Differential Revision: D40740754

Pulled By: riversand963

fbshipit-source-id: 7bde62cd6df136585bc5bfb1c426c7a8276c08e1

db/memtable.cc

@@ -784,7 +784,8 @@ Status MemTable::Add(SequenceNumber s, ValueType type,
                        std::memory_order_relaxed);
     data_size_.store(data_size_.load(std::memory_order_relaxed) + encoded_len,
                      std::memory_order_relaxed);
-    if (type == kTypeDeletion) {
+    if (type == kTypeDeletion || type == kTypeSingleDeletion ||
+        type == kTypeDeletionWithTimestamp) {
       num_deletes_.store(num_deletes_.load(std::memory_order_relaxed) + 1,
                          std::memory_order_relaxed);
     }

table/block_based/block_based_table_builder.cc

@@ -1010,7 +1010,8 @@ void BlockBasedTableBuilder::Add(const Slice& key, const Slice& value) {
   r->props.num_entries++;
   r->props.raw_key_size += key.size();
   r->props.raw_value_size += value.size();
-  if (value_type == kTypeDeletion || value_type == kTypeSingleDeletion) {
+  if (value_type == kTypeDeletion || value_type == kTypeSingleDeletion ||
+      value_type == kTypeDeletionWithTimestamp) {
     r->props.num_deletions++;
   } else if (value_type == kTypeRangeDeletion) {
     r->props.num_deletions++;