private void cleanUpInputTsBlock() {
    for (int i = 0; i < inputOperatorsCount; i++) {
      if (inputTsBlocks[i].getPositionCount() == inputIndex[i]) {
        inputTsBlocks[i] = null;
        inputIndex[i] = 0;
      }
    }
  }
Indicate whether we found an empty child input in one loop
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/queryengine/execution/operator/process/join/InnerTimeJoinOperator.java