Does DEL command delete all the elements of list/set/zset/etc ?

[torwig]

According to https://github.com/apache/incubator-kvrocks/blob/unstable/src/redis_db.cc#L117 :

rocksdb::Status Database::Del(const Slice &user_key) {
  std::string ns_key;
  AppendNamespacePrefix(user_key, &ns_key);

  std::string value;
  LockGuard guard(storage_->GetLockManager(), ns_key);
  rocksdb::Status s = db_->Get(rocksdb::ReadOptions(), metadata_cf_handle_, ns_key, &value);
  if (!s.ok()) return s;
  Metadata metadata(kRedisNone, false);
  metadata.Decode(value);
  if (metadata.Expired()) {
    return rocksdb::Status::NotFound(kErrMsgKeyExpired);
  }
  return storage_->Delete(rocksdb::WriteOptions(), metadata_cf_handle_, ns_key);
}

DEL command only deletes metadata of the list/set/zset.
What about the elements of the deleted list/set/zset? Do they stay in the storage?

[git-hulk]

Those deleted elements would be recycled when compacting: https://github.com/apache/incubator-kvrocks/blob/unstable/src/compact_filter.cc#L84

[torwig]

If I run
rpush list1 a1 a2 a3 a4 a5 a6 a7
del list1
rpush list1 b1 b2 b3
then due to the compaction filter elements a1..a7 will be recycled?

[git-hulk]

Yes, exactly.

[torwig]

Thank you.