在Firebase云函数中，我有以下批处理写入，我认为这不足以避免竞争条件，我应该使用事务来代替：

const updates = {};
updates[`rooms/${request.data.roomId}/memberTotal`] = admin.database.ServerValue.increment(1); // Increment member total
updates[`members/${request.data.roomId}_${request.auth.uid}`] = {
  dateJoined: admin.database.ServerValue.TIMESTAMP,
  userId: request.auth.uid,
};
// Perform the batch update
try {
  await admin.database().ref().update(updates);
  // success
  return {
    success: true,
  }
} catch (error) {
  throw new functions.https.HttpsError("internal", "member set error", {details: error});
}

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然而，据我所知，在实时数据库的事务中，我只能更新数据库中的一个位置。
考虑到这一点，在下面修改的代码中，我只在事务成功完成后的另一个位置插入新的member，但如果后续写入失败，这会引入一个问题，如下所示：

try {
  const transactionResult = await admin.database().ref(`rooms/${request.data.roomId}`).transaction((currentRoomData) => {
    if (currentRoomData && currentRoomData.memberTotal !== undefined) {
      // Increment member total
      currentRoomData.memberTotal = (currentRoomData.memberTotal || 0) + 1;
      return currentRoomData;
    } else {
      // If the room doesn't exist or memberTotal is undefined, abort the transaction
      return undefined;
    }
  });

  if (transactionResult.committed) {
    // Perform the update for the member after the transaction
    const memberUpdate = {};
    memberUpdate[`members/${request.data.roomId}_${request.auth.uid}`] = {
      dateJoined: admin.database.ServerValue.TIMESTAMP,
      userId: request.auth.uid,
    };
    try {
      await admin.database().ref().update(memberUpdate);
      return { success: true };
    } catch (error) {

       // DO I ROLLBACK THE INCREMENTED FIELD HERE USING ANOTER TRANSACTION??
      
       throw new functions.https.HttpsError("internal", "member set error", { details: error });
    }
    
  } else {
    throw new functions.https.HttpsError("internal", "member set transaction aborted");
  }
} catch (error) {
  throw new functions.https.HttpsError("internal", "member set transaction error", { details: error });
}

型
如果后续写入members/${request.data.roomId}_${request.auth.uid}失败，我该怎么办？
在这种错误情况下，需要回滚前一个事务，因为这个总数表示写入/members位置的成员总数，但这似乎不是一种实用的方法。
从我的main函数中删除事务并使用onValueWritten触发器来增加总数是否足以避免以下竞争条件？

onValueWritten("/members/{memberId}", (event) => {
        const roomId = context.params.roomId;

        // Reference to the counter
        const counterRef = admin.database().ref(`rooms/${roomId}/memberTotal`);

        // Run a transaction to increment the counter
        return counterRef.transaction(currentValue => {
            return (currentValue || 0) + 1;
        }).catch(error => {
            console.error('Incrementing memberTotal failed:', error);
        });
    });

型