private RegionExecutionResult processExecutionResultOfInternalCreateSchema(
        RegionExecutionResult executionResult,
        List<TSStatus> failingStatus,
        List<TSStatus> alreadyExistingStatus) {
      TSStatus executionStatus = executionResult.getStatus();

      separateMeasurementAlreadyExistException(
          failingStatus, executionStatus, alreadyExistingStatus);

      boolean isAccepted = true;
      TSStatus status;
      if (failingStatus.isEmpty() && alreadyExistingStatus.isEmpty()) {
        status = RpcUtils.SUCCESS_STATUS;
      } else if (failingStatus.isEmpty()) {
        status = RpcUtils.getStatus(alreadyExistingStatus);
      } else {
        status = RpcUtils.getStatus(failingStatus);
        isAccepted = false;
      }
      return RegionExecutionResult.create(isAccepted, status.getMessage(), status);
    }
Check the quota before creating time series.

@return null if the quota is not exceeded, otherwise return the execution result.
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/queryengine/execution/executor/RegionWriteExecutor.java