@Override
  public long ramBytesUsed() {
    return INSTANCE_SIZE
        + children.stream()
            .mapToLong(MemoryEstimationHelper::getEstimatedSizeOfAccountableObject)
            .sum()
        + MemoryEstimationHelper.getEstimatedSizeOfAccountableObject(operatorContext)
        + RamUsageEstimator.sizeOf(inputIndex)
        + RamUsageEstimator.sizeOf(canCallNext)
        + tsBlockBuilder.getRetainedSizeInBytes();
  }
If the tsBlock of tsBlockIndex is null or has no more data in the tsBlock, return true; else
return false.
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/queryengine/execution/operator/process/join/HorizontallyConcatOperator.java