bug: Some commands of Set do not have status return values from RocksDB

[Mixficsol]

Is this a regression?

Yes

Description

在 pika/src/storage/src/redis_sets.cc 下，有一些命令没有对 RocksDB 的状态返回值做判断，包括 SRemCmd, SUnionCmd, SInterCmd, SDiffCmd，以SRem命令举例，这里的 s_ 是 RocksDB 的状态返回值，我们应该对这个进行判断。

void SRemCmd::Do(std::shared_ptr<Slot> slot) {
  s_ = slot->db()->SRem(key_, members_, &deleted_);
  res_.AppendInteger(deleted_);
}

void SUnionCmd::Do(std::shared_ptr<Slot> slot) {
  std::vector<std::string> members;
  slot->db()->SUnion(keys_, &members);
  res_.AppendArrayLenUint64(members.size());
  for (const auto& member : members) {
    res_.AppendStringLenUint64(member.size());
    res_.AppendContent(member);
  }
}

void SInterCmd::Do(std::shared_ptr<Slot> slot) {
  std::vector<std::string> members;
  slot->db()->SInter(keys_, &members);
  res_.AppendArrayLenUint64(members.size());
  for (const auto& member : members) {
    res_.AppendStringLenUint64(member.size());
    res_.AppendContent(member);
  }
}

void SDiffCmd::Do(std::shared_ptr<Slot> slot) {
  std::vector<std::string> members;
  slot->db()->SDiff(keys_, &members);
  res_.AppendArrayLenUint64(members.size());
  for (const auto& member : members) {
    res_.AppendStringLenUint64(member.size());
    res_.AppendContent(member);
  }
}

可以参照在 pika/src/storage/src/redis_zets.cc 下的 ZRem命令代码，这里对 s_ 的返回值进行了判断

void ZRemCmd::Do(std::shared_ptr<Slot> slot) {
  int32_t count = 0;
  s_ = slot->db()->ZRem(key_, members_, &count);
  if (s.ok() || s.IsNotFound()) {
    AddSlotKey("z", key_, slot);
    res_.AppendInteger(count);
  } else {
    res_.SetRes(CmdRes::kErrOther, s.ToString());
  }
}

至于状态值怎么判断，我们可以查看一下 stroage 的代码，pika/src/storage/src/redis_sets.cc下，我们以SRem命令举例

rocksdb::Status RedisSets::SRem(const Slice& key, const std::vector<std::string>& members, int32_t* ret) {
  *ret = 0;
  rocksdb::WriteBatch batch;
  ScopeRecordLock l(lock_mgr_, key);

  int32_t version = 0;
  uint32_t statistic = 0;
  std::string meta_value;
  rocksdb::Status s = db_->Get(default_read_options_, handles_[0], key, &meta_value);
  if (s.ok()) {
    ParsedSetsMetaValue parsed_sets_meta_value(&meta_value);
    if (parsed_sets_meta_value.IsStale()) {
      return rocksdb::Status::NotFound("stale");
    } else if (parsed_sets_meta_value.count() == 0) {
      return rocksdb::Status::NotFound();
    } else {
      int32_t cnt = 0;
      std::string member_value;
      version = parsed_sets_meta_value.version();
      for (const auto& member : members) {
        SetsMemberKey sets_member_key(key, version, member);
        s = db_->Get(default_read_options_, handles_[1], sets_member_key.Encode(), &member_value);
        if (s.ok()) {
          cnt++;
          statistic++;
          batch.Delete(handles_[1], sets_member_key.Encode());
        } else if (s.IsNotFound()) {
        } else {
          return s;
        }
      }
      *ret = cnt;
      if (!parsed_sets_meta_value.CheckModifyCount(-cnt)){
        return Status::InvalidArgument("set size overflow");
      }
      parsed_sets_meta_value.ModifyCount(-cnt);
      batch.Put(handles_[0], key, meta_value);
    }
  } else if (s.IsNotFound()) {
    *ret = 0;
    return rocksdb::Status::NotFound();
  } else {
    return s; // 对于返回状态不OK的值我们应该及时打印出报错
  }
  s = db_->Write(default_write_options_, &batch);
  UpdateSpecificKeyStatistics(key.ToString(), statistic);
  return s;
}

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