Question about the format comments in Add and Put methods of Memtable.

[gukj-spel]

Hello, Recently I am learning leveldb by reading its source code. When I saw this function fallow:

void MemTable::Add(SequenceNumber s, ValueType type, const Slice& key,
                   const Slice& value) {
  // Format of an entry is concatenation of:
  //  key_size     : varint32 of internal_key.size()
  //  key bytes    : char[internal_key.size()]
  //  tag          : uint64((sequence << 8) | type)
  //  value_size   : varint32 of value.size()
  //  value bytes  : char[value.size()]

I have a question about this comments of key bytes format. Shouldn't it' s size be the user_key 's size which equal to internal_key.size() - 8? Why this comment say its size is the size of the internal_key?

[felipecrv]

Because it would be more complicated to manipulate the full entries if one had to always add 8 to get the size of the key part.

[gukj-spel]

Because it would be more complicated to manipulate the full entries if one had to always add 8 to get the size of the key part.

Oh, yeah. Thank you for the answer. 😊