AINode

AINode is an IoTDB native node designed to support the registration, management, and invocation of large-scale time series models. It comes with industry-leading proprietary time series models such as Timer and Sundial. These models can be invoked through standard SQL statements, enabling real-time inference of time series data at the millisecond level, and supporting application scenarios such as trend forecasting, missing value imputation, and anomaly detection for time series data.

The system architecture is shown below:

The responsibilities of the three nodes are as follows:

• ConfigNode: responsible for storing and managing the meta-information of the model; responsible for distributed node management.
• DataNode: responsible for receiving and parsing SQL requests from users; responsible for storing time-series data; responsible for preprocessing computation of data.
• AINode: responsible for model file import creation and model inference.

1. Advantageous features

Compared with building a machine learning service alone, it has the following advantages:

• Simple and easy to use: no need to use Python or Java programming, the complete process of machine learning model management and inference can be completed using SQL statements. Creating a model can be done using the CREATE MODEL statement, and using a model for inference can be done using the SELECT * FROM FORECAST (...) statement, making it simpler and more convenient to use.

• Avoid Data Migration: With IoTDB native machine learning, data stored in IoTDB can be directly applied to the inference of machine learning models without having to move the data to a separate machine learning service platform, which accelerates data processing, improves security, and reduces costs.

• Built-in Advanced Algorithms: supports industry-leading machine learning analytics algorithms covering typical timing analysis tasks, empowering the timing database with native data analysis capabilities. Such as:
  • Time Series Forecasting: learns patterns of change from past time series; thus outputs the most likely prediction of future series based on observations at a given past time.
  • Anomaly Detection for Time Series: detects and identifies outliers in a given time series data, helping to discover anomalous behaviour in the time series.
  • Annotation for Time Series (Time Series Annotation): Adds additional information or markers, such as event occurrence, outliers, trend changes, etc., to each data point or specific time period to better understand and analyse the data.

2. Basic Concepts

• Model: A machine learning model takes time series data as input and outputs analysis task results or decisions. Models are the basic management units of AINode, supporting model operations such as creation (registration), deletion, query, modification (fine-tuning), and usage (inference).
• Create: Load externally designed or trained model files/algorithms into AINode for unified management and usage by IoTDB.
• Inference: Use the created model to complete time series analysis tasks applicable to the model on specified time series data.
• Built-in Capabilities: AINode comes with machine learning algorithms or self-developed models for common time series analysis scenarios (e.g., forecasting and anomaly detection).
  

3. Installation and Deployment

The deployment of AINode can be found in the document Deployment Guidelines .

4. Usage Guide

AINode provides model creation and deletion functions for time series models. Built-in models do not require creation and can be used directly.

4.1 Registering Models

Trained deep learning models can be registered by specifying their input and output vector dimensions for inference.

Models that meet the following criteria can be registered with AINode:

1. AINode currently supports models trained with PyTorch 2.4.0. Features above version 2.4.0 should be avoided.
2. AINode supports models stored using PyTorch JIT (model.pt), which must include both the model structure and weights.
3. The model input sequence can include single or multiple columns. If multi-column, it must match the model capabilities and configuration file.
4. Model configuration parameters must be clearly defined in the config.yaml file. When using the model, the input and output dimensions defined in config.yaml must be strictly followed. Mismatches with the configuration file will cause errors.

The SQL syntax for model registration is defined as follows:

create model <model_name> using uri <uri>

Detailed meanings of SQL parameters:

• model_name: The global unique identifier for the model, non-repeating. Model names have the following constraints:

  • Allowed characters: [0-9 a-z A-Z _] (letters, numbers, underscores)
  • Length: 2-64 characters
  • Case-sensitive

• uri: The resource path of the model registration files, which should include the model structure and weight file model.pt and the model configuration file config.yaml

  • Model structure and weight file: The weight file generated after model training, currently supporting .pt files from PyTorch training.

  • Model configuration file: Parameters related to the model structure provided during registration, which must include input and output dimensions for inference:

  Parameter Name	Description	Example
  input_shape	Rows and columns of model input	[96,2]
  output_shape	Rows and columns of model output	[48,2]

  In addition to inference, data types of input and output can also be specified:

  Parameter Name	Description	Example
  input_type	Data type of model input	['float32', 'float32']
  output_type	Data type of model output	['float32', 'float32']

  Additional notes can be specified for model management display:

  Parameter Name	Description	Example
  attributes	Optional notes set by users for model display	'model_type': 'dlinear', 'kernel_size': '25'

In addition to registering local model files, remote resource paths can be specified via URIs for registration, using open-source model repositories (e.g., HuggingFace).

Example

The current example folder contains model.pt (trained model) and config.yaml with the following content:

configs:                
    # Required
    input_shape: [96, 2]      # Model accepts 96 rows x 2 columns of data
    output_shape: [48, 2]     # Model outputs 48 rows x 2 columns of data
    
    # Optional (default to all float32, column count matches shape)
    input_type: ["int64", "int64"]  # Data types of inputs, must match input column count
    output_type: ["text", "int64"]  # Data types of outputs, must match output column count

attributes:           # Optional user-defined notes
   'model_type': 'dlinear'
   'kernel_size': '25'

Register the model by specifying this folder as the loading path:

IoTDB> create model dlinear_example using uri "file://./example"

Models can also be downloaded from HuggingFace for registration:

IoTDB> create model dlinear_example using uri "https://huggingface.co/google/timesfm-2.0-500m-pytorch"

After SQL execution, registration proceeds asynchronously. The registration status can be checked via model display (see Model Display section). The registration success time mainly depends on the model file size.

Once registered, the model can be invoked for inference through normal query syntax.

4.2 Viewing Models

Registered models can be queried using the show models command. The SQL definitions are:

show models

show models <model_name>

In addition to displaying all models, specifying a model_id shows details of a specific model. The display includes:

ModelId	State	Configs	Attributes
Unique ID	Registration status (INACTIVE, LOADING, ACTIVE,TRAINING,FAILED, DROPPING)	InputShape, outputShape, inputTypes, outputTypes	User notes

State descriptions:

• INACTIVE: The model is in an unavailable state.
• LOADING: The model is being loaded.
• ACTIVE: The model is in an available state.
• TRAINING: The model is in the fine-tuning state.
• FAILED: The model fine-tuning failed.
• DROPPING: The model is being deleted.

Example

IoTDB> show models

+---------------------+--------------------+--------+--------+
|              ModelId|           ModelType|Category|   State|
+---------------------+--------------------+--------+--------+
|                arima|               Arima|BUILT-IN|  ACTIVE|
|          holtwinters|         HoltWinters|BUILT-IN|  ACTIVE|
|exponential_smoothing|ExponentialSmoothing|BUILT-IN|  ACTIVE|
|     naive_forecaster|     NaiveForecaster|BUILT-IN|  ACTIVE|
|       stl_forecaster|       StlForecaster|BUILT-IN|  ACTIVE|
|         gaussian_hmm|         GaussianHmm|BUILT-IN|  ACTIVE|
|              gmm_hmm|              GmmHmm|BUILT-IN|  ACTIVE|
|                stray|               Stray|BUILT-IN|  ACTIVE|
|             timer_xl|            Timer-XL|BUILT-IN|  ACTIVE|
|              sundial|       Timer-Sundial|BUILT-IN|  ACTIVE|
+---------------------+--------------------+--------+--------+

4.3 Deleting Models

Registered models can be deleted via SQL, which removes all related files under AINode:

drop model <model_id>

Specify the registered model_id to delete the model. Since deletion involves data cleanup, the operation is not immediate, and the model state becomes DROPPING, during which it cannot be used for inference. Note: Built-in models cannot be deleted.

4.4 Inference with Built-in Models

SQL syntax:

SELECT * FROM forecast(
   input, 
   model_id,
   [output_length, 
   output_start_time,
   output_interval,
   timecol, 
   preserve_input,
   model_options]?
)

Built-in models do not require prior registration for inference. Simply use the forecast function and specify the model_id to invoke the model's inference capabilities.

• Note: Inference with built-in time series large models requires local availability of model weights in the directory /IOTDB_AINODE_HOME/data/ainode/models/weights/model_id/. If weights are missing, they will be automatically downloaded from HuggingFace. Ensure direct network access to HuggingFace.

Parameter descriptions:

Parameter	Type	Attribute	Description	Required	Notes
input	Table	SET SEMANTIC	Input data for forecasting	Yes
model_id	String	Scalar	Name of the model to use	Yes	Must be non-empty and a built-in model; otherwise, errors like "MODEL_ID cannot be null" occur.
output_length	INT32	Scalar (default: 96)	Size of the output forecast window	No	Must be > 0.
output_start_time	Timestamp	Scalar (default: last input timestamp + output_interval)	Start timestamp of the forecast results	No	Can be negative (before 1970-01-01).
output_interval	Time interval	Scalar (default: inferred from input)	Time interval between forecast points (supports ns, us, ms, s, m, h, d, w)	No	If > 0, uses user-specified interval; else, infers from input.
timecol	String	Scalar (default: "time")	Name of the timestamp column	No	Must exist in input and be of TIMESTAMP type; otherwise, errors occur.
preserve_input	Boolean	Scalar (default: false)	Retain all input rows in the output	No
model_options	String	Scalar (default: empty)	Model-specific key-value pairs (e.g., normalization)	No	Unsupported parameters are ignored. See appendix for built-in model parameters.

Notes:

1. The forecast function predicts all columns in the input table by default (excluding the time column and columns specified in partition by).
2. The forecast function does not require the input data to be in any specific order. It sorts the input data in ascending order by the timestamp (specified by the TIMECOL parameter) before invoking the model for prediction.
3. Different models have different requirements for the number of input data rows:
   • If the input data has fewer rows than the minimum requirement, an error will be thrown.
   • If the input data exceeds the maximum row limit, the last rows that meet the requirement will be automatically truncated for processing.
   • Among the currently built-in models in AINode, only sundial has a row limit. It supports a maximum of 2880 input rows. If exceeded, the last 2880 rows will be automatically used.
4. The result columns of the forecast function include all input columns from the input table, with their original data types preserved. If preserve_input = true, an additional is_input column will be included to indicate whether a row is from the input data.
   • Currently, only columns of type INT32, INT64, FLOAT, or DOUBLE are supported for prediction. Otherwise, an error will occur: "The type of the column [%s] is [%s], only INT32, INT64, FLOAT, DOUBLE is allowed."
5. output_start_time and output_interval only affect the generation of the timestamp column in the output results. Both are optional parameters:
   • output_start_time defaults to the last timestamp of the input data plus output_interval.
   • output_interval defaults to the sampling interval of the input data, calculated as: (last timestamp - first timestamp) / (number of rows - 1).
   • The timestamp of the Nth output row is calculated as: output_start_time + (N - 1) * output_interval.

Example

Using the ETTh1-tab dataset:ETTh1-tab。

View supported models

IoTDB:etth> show models
+---------------------+--------------------+--------+------+
|              ModelId|           ModelType|Category| State|
+---------------------+--------------------+--------+------+
|                arima|               Arima|BUILT-IN|ACTIVE|
|          holtwinters|         HoltWinters|BUILT-IN|ACTIVE|
|exponential_smoothing|ExponentialSmoothing|BUILT-IN|ACTIVE|
|     naive_forecaster|     NaiveForecaster|BUILT-IN|ACTIVE|
|       stl_forecaster|       StlForecaster|BUILT-IN|ACTIVE|
|         gaussian_hmm|         GaussianHmm|BUILT-IN|ACTIVE|
|              gmm_hmm|              GmmHmm|BUILT-IN|ACTIVE|
|                stray|               Stray|BUILT-IN|ACTIVE|
|              sundial|       Timer-Sundial|BUILT-IN|ACTIVE|
|             timer_xl|            Timer-XL|BUILT-IN|ACTIVE|
+---------------------+--------------------+--------+------+
Total line number = 10
It costs 0.004s

Inference with sundial model:

IoTDB:etth> select Time, HUFL,HULL,MUFL,MULL,LUFL,LULL,OT from eg LIMIT 96
+-----------------------------+------+-----+-----+-----+-----+-----+------+
|                         Time|  HUFL| HULL| MUFL| MULL| LUFL| LULL|    OT|
+-----------------------------+------+-----+-----+-----+-----+-----+------+
|2016-07-01T00:00:00.000+08:00| 5.827|2.009|1.599|0.462|4.203| 1.34|30.531|
|2016-07-01T01:00:00.000+08:00| 5.693|2.076|1.492|0.426|4.142|1.371|27.787|
|2016-07-01T02:00:00.000+08:00| 5.157|1.741|1.279|0.355|3.777|1.218|27.787|
|2016-07-01T03:00:00.000+08:00|  5.09|1.942|1.279|0.391|3.807|1.279|25.044|
......
Total line number = 96
It costs 0.119s

IoTDB:etth> select * from forecast( 
     model_id => 'sundial',
     input => (select Time, ot from etth.eg where time >= 2016-08-07T18:00:00.000+08:00 limit 1440) order BY time,
     output_length => 96
)
+-----------------------------+---------+
|                         time|       ot|
+-----------------------------+---------+
|2016-10-06T18:00:00.000+08:00|20.781654|
|2016-10-06T19:00:00.000+08:00|20.252121|
|2016-10-06T20:00:00.000+08:00|19.960138|
|2016-10-06T21:00:00.000+08:00|19.662334|
......
Total line number = 96
It costs 1.615s

4.5 Fine-tuning Built-in Models

Only Timer-XL and Timer-Sundial support fine-tuning.

The SQL syntax is as follows:

create model <model_id> (with hyperparameters 
(<parameterName>=<parameterValue>(, <parameterName>=<parameterValue>)*))?
from model <existing_model_id>
on dataset (inputSql)

Example

1. Select the first 80% of data from the measurement ot as the fine-tuning dataset, and create the model sundialv3 based on sundial.

IoTDB> set sql_dialect=table
Msg: The statement is executed successfully.
IoTDB> CREATE MODEL sundialv3 FROM MODEL sundial ON DATASET ('SELECT time, ot from etth.eg where 1467302400000 <= time and time < 1517468400001')
Msg: The statement is executed successfully.
IoTDB> show models
+---------------------+--------------------+----------+--------+
|              ModelId|           ModelType|  Category|   State|
+---------------------+--------------------+----------+--------+
|                arima|               Arima|  BUILT-IN|  ACTIVE|
|          holtwinters|         HoltWinters|  BUILT-IN|  ACTIVE|
|exponential_smoothing|ExponentialSmoothing|  BUILT-IN|  ACTIVE|
|     naive_forecaster|     NaiveForecaster|  BUILT-IN|  ACTIVE|
|       stl_forecaster|       StlForecaster|  BUILT-IN|  ACTIVE|
|         gaussian_hmm|         GaussianHmm|  BUILT-IN|  ACTIVE|
|              gmm_hmm|              GmmHmm|  BUILT-IN|  ACTIVE|
|                stray|               Stray|  BUILT-IN|  ACTIVE|
|              sundial|       Timer-Sundial|  BUILT-IN|  ACTIVE|
|             timer_xl|            Timer-XL|  BUILT-IN|  ACTIVE|
|            sundialv2|       Timer-Sundial|FINE-TUNED|  ACTIVE|
|            sundialv3|       Timer-Sundial|FINE-TUNED|TRAINING|
+---------------------+--------------------+----------+--------+

2. The fine-tuning task starts asynchronously in the background, and logs can be viewed in the AINode process. After fine-tuning is complete, query and use the new model

IoTDB> show models
+---------------------+--------------------+----------+------+
|              ModelId|           ModelType|  Category| State|
+---------------------+--------------------+----------+------+
|                arima|               Arima|  BUILT-IN|ACTIVE|
|          holtwinters|         HoltWinters|  BUILT-IN|ACTIVE|
|exponential_smoothing|ExponentialSmoothing|  BUILT-IN|ACTIVE|
|     naive_forecaster|     NaiveForecaster|  BUILT-IN|ACTIVE|
|       stl_forecaster|       StlForecaster|  BUILT-IN|ACTIVE|
|         gaussian_hmm|         GaussianHmm|  BUILT-IN|ACTIVE|
|              gmm_hmm|              GmmHmm|  BUILT-IN|ACTIVE|
|                stray|               Stray|  BUILT-IN|ACTIVE|
|              sundial|       Timer-Sundial|  BUILT-IN|ACTIVE|
|             timer_xl|            Timer-XL|  BUILT-IN|ACTIVE|
|            sundialv2|       Timer-Sundial|FINE-TUNED|ACTIVE|
|            sundialv3|       Timer-Sundial|FINE-TUNED|ACTIVE|
+---------------------+--------------------+----------+------+

4.6 Time Series Large Model Import Steps

AINode supports multiple time series large models. For deployment, refer to Time Series Large Model

5 Permission Management

AINode uses IoTDB's authentication for permission management. Users need USE_MODEL permission for model management and READ_DATA permission for inference (to access input data sources).

Permission	Scope	Admin (ROOT)	Regular User	Path-Related
USE_MODEL	Create/Show/Drop models	✔️	✔️	❌
READ_DATA	Call inference functions	✔️	✔️	✔️

6 Appendix

Arima

Parameter	Description	Default
order	ARIMA order (p, d, q): p=autoregressive, d=differencing, q=moving average.	(1,0,0)
seasonal_order	Seasonal ARIMA order (P, D, Q, s): seasonal AR, differencing, MA orders, and season length (e.g., 12 for monthly data).	(0,0,0,0)
method	Optimizer: 'newton', 'nm', 'bfgs', 'lbfgs', 'powell', 'cg', 'ncg', 'basinhopping'.	'lbfgs'
maxiter	Maximum iterations/function evaluations.	50
out_of_sample_size	Number of tail samples for validation (not used in fitting).	0
scoring	Scoring function for validation (sklearn metric or custom).	'mse'
trend	Trend term configuration. If with_intercept=True and None, defaults to 'c' (constant).	None
with_intercept	Include intercept term.	True
time_varying_regression	Allow regression coefficients to vary over time.	False
enforce_stationarity	Enforce stationarity of AR components.	True
enforce_invertibility	Enforce invertibility of MA components.	True
simple_differencing	Use differenced data for estimation (sacrifices first rows).	False
measurement_error	Assume observation errors.	False
mle_regression	Use maximum likelihood for regression (must be False if time_varying_regression=True).	True
hamilton_representation	Use Hamilton representation (default is Harvey).	False
concentrate_scale	Exclude scale parameter from likelihood (reduces parameters).	False

NaiveForecaster

Parameter	Description	Default
strategy	Forecasting strategy: - "last": Use last training value (seasonal if sp>1). - "mean": Use mean of last window (seasonal if sp>1). - "drift": Fit line through last window and extrapolate (non-robust to NaN).	"last"
sp	Seasonal period. None or 1 means no seasonality; 12 means monthly.	1

STLForecaster

Parameter	Description	Default
sp	Seasonal period (units). Passed to statsmodels' STL.	2
seasonal	Seasonal smoothing window (odd ≥3, typically ≥7).	7
seasonal_deg	LOESS polynomial degree for season (0=constant, 1=linear).	1
trend_deg	LOESS polynomial degree for trend (0 or 1).	1
low_pass_deg	LOESS polynomial degree for low-pass (0 or 1).	1
seasonal_jump	Interpolation step for season LOESS (larger = faster).	1
trend_jump	Interpolation step for trend LOESS (larger = faster).	1
low_pass_jump	Interpolation step for low-pass LOESS.	1

ExponentialSmoothing (HoltWinters)

Parameter	Description	Default
damped_trend	Use damped trend (trend flattens instead of growing infinitely).	True
initialization_method	Initialization method: - "estimated": Fit to estimate initial states - "heuristic": Use heuristic for initial level/trend/season - "known": User-provided initial values - "legacy-heuristic": Legacy compatibility	"estimated"
optimized	Optimize parameters via maximum likelihood.	True
remove_bias	Remove bias to make residuals' mean zero.	False
use_brute	Use brute-force grid search for initial parameters.