Construct ETL Information Pipeline in ML

From information processing to fast insights, sturdy pipelines are a should for any ML system. Typically the Information Staff, comprising Data and ML Engineers, must construct this infrastructure, and this expertise will be painful. Nonetheless, environment friendly use of ETL pipelines in ML may also help make their life a lot simpler.

This text explores the significance of ETL pipelines in machine studying, a hands-on instance of constructing ETL pipelines with a preferred software, and suggests the very best methods for information engineers to boost and maintain their pipelines. We additionally talk about various kinds of ETL pipelines for ML use instances and supply real-world examples of their use to assist information engineers select the precise one.

Earlier than delving into the technical particulars, let’s evaluate some basic ideas.

What’s an ETL information pipeline in ML?

An ETL data pipeline is a group of instruments and actions to carry out Extract(E), Rework(T), and Load(L) for the required information. 

Illustration of ETL pipeline
ETL pipeline | Supply: Creator

These actions contain extracting information from one system, reworking it, after which processing it into one other goal system the place it may be saved and managed. 

ML closely depends on ETL pipelines because the accuracy and effectiveness of a mannequin are immediately impacted by the standard of the coaching information. These pipelines help information scientists in saving effort and time by making certain that the info is clear, correctly formatted, and prepared to be used in machine studying duties.

Furthermore, ETL pipelines play an important position in breaking down information silos and establishing a single supply of fact. Let’s have a look at the significance of ETL pipelines intimately.

Significance of ETL pipeline in machine studying

The importance of ETL pipelines lies in the truth that they allow organizations to derive useful insights from massive and sophisticated information units. Listed here are some particular the reason why they’re essential:

  • Information Integration: Organizations can combine information from numerous sources utilizing ETL pipelines. This gives information scientists with a unified view of the info and helps them resolve how the mannequin must be skilled, values for hyperparameters, and so forth.
  • Information High quality Test: As the info flows by means of the combination step, ETL pipelines can then assist enhance the standard of information by standardizing, cleansing, and validating it. This ensures that the info which can be used for ML is correct, dependable, and constant.
  • Save Time: As ETL pipelines automate the method of three main steps – Extract, Rework, and Load, this helps in saving plenty of time and likewise reduces the chance of human errors. This permits information scientists to maintain their concentrate on the creation of fashions or their steady enchancment.
  • Scalable: Fashionable ETL pipelines are scalable, i.e., they are often scaled up or down relying on the quantity of information it must course of. Mainly, it comes with the flexibleness and agility to make any modifications primarily based on enterprise wants. 

In-Depth ETL in Machine Learning Tutorial – Case Study With Neptune

ETL pipeline vs. information pipeline: the variations 

Information pipeline is an umbrella time period for the class of shifting information between totally different programs, and ETL information pipeline is a sort of information pipeline.


It is not uncommon to make use of ETL information pipeline and information pipeline interchangeably. Despite the fact that each these phrases discuss with functionalities and processes of passing information from numerous sources to a single repository, they aren’t the identical. Let’s discover why we shouldn’t be utilizing them synonymously.


ETL Pipeline

Information Pipeline

Because the abbreviation suggests, ETL includes a sequence of processes, extracting the info, reworking it and on the finish loading it to the goal supply.

An information pipeline additionally includes shifting information from one supply to a different however doesn’t essentially should undergo information transformation.

ETL helps to rework the uncooked information right into a structured format that may be simply out there for information scientists to create fashions and interpret for any data-driven choice.

An information pipeline is created with the main focus of transferring information from quite a lot of sources into a knowledge warehouse. Additional processes or workflows can then simply make the most of this information to create enterprise intelligence and analytics options.

ETL pipeline runs on schedule e.g. day by day, weekly or month-to-month. Primary ETL pipelines are batch-oriented, the place information is moved in chunks on a specified schedule.

Information pipelines typically run real-time processing. Information will get up to date constantly and helps real-time reporting and evaluation.

In abstract, ETL pipelines are a sort of information pipeline that’s particularly designed for extracting information from a number of sources, reworking it into a typical format, and loading it into a knowledge warehouse or different storage system. Whereas a knowledge pipeline can embrace numerous forms of pipelines, ETL pipeline is one particular subset of a knowledge pipeline. 

We went by means of the essential structure of an ETL pipeline and noticed how every step will be carried out for various functions, and we are able to select from numerous instruments to finish every step. The ELT structure and its kind differ from group to group as they’ve totally different units of tech stack, information sources, and enterprise necessities.

What are the various kinds of ETL pipelines in ML?

ETL pipelines will be categorized primarily based on the kind of information being processed and the way it’s being processed. Listed here are a number of the varieties:

  • Batch ETL Pipeline: It is a conventional ETL strategy that includes the processing of enormous quantities of information directly in batches. The information is extracted from a number of sources, remodeled into the specified format, and loaded right into a goal system, comparable to a knowledge warehouse. Batch ETL is especially helpful for coaching fashions on historic information or operating periodic batch processing jobs.
  • Actual-time ETL Pipeline: This processes information because it arrives in near-real-time or real-time; processing information constantly means a smaller quantity of processing capability is required at anyone time, and spikes in utilization will be prevented. Stream/ Actual-time ETL is especially helpful for functions comparable to fraud detection, the place real-time processing is important. The true-time ETL pipelines require instruments and applied sciences like stream processing engines and messaging programs.
  • Incremental ETL Pipeline: These pipelines solely extract and course of information that has modified for the reason that final run as a substitute of processing the complete dataset. They’re helpful for conditions the place the supply information modifications incessantly, however the goal system solely wants the most recent information e.g. functions comparable to suggestion programs, the place the info modifications incessantly however not in real-time.
  • Cloud ETL Pipeline: Cloud ETL pipeline for ML includes utilizing cloud-based providers to extract, remodel, and cargo information into an ML system for coaching and deployment. Cloud suppliers comparable to AWS, Microsoft Azure, and GCP provide a variety of instruments and providers that can be utilized to construct these pipelines. For instance, AWS gives providers comparable to AWS Glue for ETL, Amazon S3 for information storage, and Amazon SageMaker for ML coaching and deployment.
  • Hybrid ETL Pipeline: These pipelines mix batch and real-time processing, leveraging the strengths of each approaches. Hybrid ETL pipelines can course of massive batches of information at predetermined intervals and likewise seize real-time updates to the info as they arrive. Hybrid ETL is especially helpful for functions comparable to predictive upkeep, the place a mixture of real-time and historic information is required to coach fashions.

ETL pipeline instruments

To create an ETL pipeline, as mentioned within the final part, we require instruments, instruments that may present us the performance of following primary ETL structure steps. There are a number of instruments out there out there, listed here are a number of the well-liked ones, together with the options they supply.

Comparing Tools For Data Processing Pipelines

construct an ML ETL pipeline?

Within the earlier part, we briefly explored some primary ETL ideas and instruments, on this part, we can be discussing how we are able to leverage them to construct an ETL pipeline. First, let’s discuss its structure.

ETL structure

The distinctive characteristic of the ETL structure is that information goes by means of all required preparation procedures earlier than it reaches the warehouse. Because of this, the ultimate repository comprises clear, full, and reliable information for use additional with out amendments.


ETL structure typically features a diagram just like the one above that outlines the circulate of knowledge within the ETL pipeline from information sources to the ultimate vacation spot. It includes three important areas: Touchdown space, Staging space, and Information Warehouse space.

  • The Touchdown Space is the primary vacation spot for information after being extracted from the supply location. It might retailer a number of batches of information earlier than shifting it by means of the ETL pipeline.
  • The Staging Space is an intermediate location for performing ETL transformations.
  • The Information Warehouse Space is the ultimate vacation spot for information in an ETL pipeline. It’s used for analyzing information to acquire useful insights and make higher enterprise choices. 

ETL information pipeline structure is layered. Every subsystem is crucial, and sequentially, every sub-system feeds into the subsequent till information reaches its vacation spot.

Illustration of ETL data pipeline architecture
ETL information pipeline structure | Supply: Creator
  1. Information Discovery: Information will be sourced from numerous forms of programs, comparable to databases, file programs, APIs, or streaming sources. We additionally want information profiling i.e. information discovery, to know if the info is acceptable for ETL. This includes trying on the information construction, relationships, and content material.
  1. Ingestion: You’ll be able to pull the info from the varied information sources right into a staging space or information lake. Extraction will be completed utilizing numerous strategies comparable to APIs, direct database connections, or file transfers. The information will be extracted all of sudden(extracting from a DB) or incrementally(extracting utilizing APIs), or when there’s a change(extracting information from cloud storage like S3 on a set off). 
  1. Transformations: This stage includes cleansing, enriching, and shaping the info to suit the goal system necessities. Information will be manipulated utilizing numerous strategies comparable to filtering, aggregating, becoming a member of, or making use of complicated enterprise guidelines. Earlier than manipulating the info, we additionally want to wash the info, which requires eliminating any duplicate entries, dropping irrelevant information, and figuring out misguided information. This helps to enhance information accuracy and reliability for ML algorithms.
  1. Information Storage: Shops the remodeled information in an appropriate format that can be utilized by the ML fashions. The storage system may very well be a database, a knowledge warehouse, or a cloud-based object retailer. The information will be saved in a structured or unstructured format, relying on the system’s necessities.
  2. Characteristic Engineering: Characteristic engineering includes deciding on, reworking, and mixing uncooked information to create significant options that can be utilized for ML fashions. It immediately impacts the accuracy and interpretability of the mannequin. Efficient characteristic engineering requires area information, creativity, and iterative experimentation to find out the optimum set of options for a selected drawback.

Let’s construct our personal ETL pipeline now utilizing one of many mentioned instruments!

Constructing ETL pipeline utilizing AirFlow

Think about we wish to create a machine studying classification mannequin that is ready to classify flowers into 3 totally different classes – Setosa, Versicolour, Virginica. We’re going to use a dataset that will get up to date, say, each week. This appears like a job for Batch ETL information pipeline.

To arrange a batch ETL information pipeline, we’re going to use Apache Airflow, which is an open supply workflow administration system and provides a simple approach to write, schedule and monitor ETL workflows. Observe the steps talked about beneath to arrange your personal Batch ETL pipeline.

Listed here are the generic steps which we are able to comply with to create ETL workflow in AirFlow:

  1. Arrange an Airflow atmosphere: Set up and configure Airflow in your system. You’ll be able to discuss with the set up steps here.
  2. Outline the DAG & configure the workflow: Outline a Directed Acyclic Graph (DAG) in Airflow to orchestrate the ETL pipeline for our ML classifier. DAG could have a group of duties with dependencies between them. For this train, we’re utilizing a python operator to outline the duties, and we’re going to hold DAG’s schedule as ‘None’ as we can be operating the pipeline manually.

Create a DAG file – with the beneath code:

from datetime import timedelta

from airflow import DAG

from airflow.operators.python import PythonOperator
from airflow.operators.empty import EmptyOperator
from airflow.operators.bash import BashOperator
from airflow.utils.dates import days_ago

from python_functions import download_dataset 
from python_functions import data_preprocessing
from python_functions import ml_training_classification

with DAG(
    description='Classification ML pipeline',
    schedule = None,  
 ) as dag:

 task_download_dataset = PythonOperator(

 task_data_preprocessing = PythonOperator(

 task_ml_training_classification = PythonOperator(

task_download_dataset >> task_data_preprocessing >> task_ml_training_classification

  1. Implement the ETL duties: Implement every process outlined within the DAG. These duties will embrace loading iris dataset from scikit-learn dataset package deal, reworking the info, and utilizing the refined dataframe to create a machine studying mannequin. 

Create a python operate file that consists of all of the ETL duties –

from sklearn.datasets import load_iris
from sklearn.model_selection import train_test_split
from sklearn.ensemble import RandomForestClassifier
from sklearn.metrics import confusion_matrix
from sklearn.metrics import accuracy_score

import pandas as pd
import numpy as np 

def download_dataset():

    iris = load_iris()
    iris_df = pd.DataFrame(
              information = np.c_[iris['data'], iris['target']],
              columns = iris['feature_names'] + ['target'])


def data_preprocessing():

    iris_transform_df = pd.read_csv("iris_dataset.csv",index_col=0)
    cols = ["sepal length (cm)","sepal width (cm)","petal length (cm)","petal width (cm)"]
    iris_transform_df[cols] = iris_transform_df[cols].fillna(

  1. Monitor and handle the pipeline: Now that the DAG and workflow code are prepared, we are able to now monitor our total ETL for ML on the Airflow server.

1. Get the DAG listed within the Airflow server.

DAG listed in the Airflow Server
DAG listed within the Airflow server | Supply: Creator

2. Test the workflow graph and Run the pipeline (Set off the DAG):

The workflow graph in Airflow Server
The workflow graph | Supply: Creator

3. Monitor & examine logs: After you set off the DAG, you possibly can monitor the progress of DAG within the UI. Under pictures present that every one 3 steps have been profitable.

Monitoring the progress of DAG in the UI
Monitoring the progress of DAG within the UI | Supply: Creator

There’s a approach to examine how a lot time every process has taken utilizing Gantt chart within the UI:

Checking how much time each task has taken using Gantt chart
Checking how a lot time every process has taken utilizing a Gantt chart | Supply: Creator

On this train, we created an ETL workflow utilizing DAG and didn’t set any schedule, however you possibly can attempt setting the schedule to no matter you want and monitor the pipeline. You can even attempt utilizing a dataset which will get up to date incessantly and primarily based on that resolve to set the schedule. 

You can even scale airflow orchestration by attempting totally different operators and executors. In case you are thinking about exploring the Actual-time ETL information pipeline, please comply with this tutorial.

Greatest practices round constructing ETL pipelines in ML

For data-driven organizations, a strong ETL pipeline is crucial. This includes:

  • 1
    Managing information sources successfully
  • 2
    Making certain information high quality and accuracy
  • 3
    Optimizing information circulate for environment friendly processing

Integrating machine studying fashions with information analytics empowers organizations with superior capabilities to foretell demand with enhanced accuracy.

There are a number of finest practices for constructing an ETL (Extract, Rework, Load) pipeline for Machine Studying (ML) functions. Listed here are a number of the most essential ones –

  • Begin with a transparent understanding of the necessities. Establish the info sources you will want to assist a machine studying mannequin. Guarantee that you’re utilizing applicable information varieties. This helps to substantiate information is appropriately formatted, which is essential for ML algorithms to course of the info effectively. Begin with a subset of information and regularly scale up, this helps to maintain a examine on additional duties/processes.
  • Correcting or eradicating inaccuracies and inconsistencies from the info. That is essential as a result of ML algorithms will be delicate to inconsistency and outliers within the information. 
  • Safe your information, implement entry management to make sure role-based entry to the info.
  • Make use of distributed file programs, parallelism, staging tables or caching strategies, the place potential. This could pace up the processing of information and may also help optimise your pipeline. This finally helps to enhance the efficiency of the ML mannequin.
  • Schedule or automate the data-driven workflows to maneuver and remodel the info throughout numerous sources.
  • Monitoring and logging your ETL information which can be utilized by your machine studying fashions. E.g. you wish to hold observe of any information drifts which could have an effect on your ML mannequin efficiency. 
  • Preserve model management of your ETL code base. This helps to trace any modifications, collaborate with different builders and be certain that the pipeline is operating in the identical method as anticipated and received’t influence your mannequin’s efficiency.
  • In case you are utilizing any cloud-based providers, use their ETL templates to avoid wasting time creating every thing from scratch.

Building ML Pipeline: 6 Problems & Solutions [From a Data Scientist’s Experience]


All through this text, we walked by means of totally different points of ETL information pipeline in ML.

  • 1
    ETL pipeline is essential for creating a very good machine studying mannequin.
  • 2
    Relying on information and the requirement how we are able to setup ETL structure and use various kinds of ETL information pipelines.
  • 3
    Constructing Batch ETL pipeline utilizing Airflow the place we are able to automate the ETL processes. We will additionally log and monitor the workflows to maintain a watch on every thing that goes round.
  • 4
    create scalable and environment friendly ETL information pipelines .

I hope this text was helpful for you. By referring to this text and the hands-on train of making the batch pipeline, you need to have the ability to create one by yourself. You’ll be able to select any software talked about within the article and begin your journey.

Completely happy Studying!


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