Data Warehousing: Data(base) Mirroring in Microsoft Fabric (New feature)

Data Warehousing Series

Microsoft recently announced [4] the preview of a new Fabric feature called Mirroring, a low-cost, low-latency fully managed service that allows to replicate data from various systems together into OneLake [1]. Currently only Azure SQL Database, Azure Cosmos DB, and Snowflake are supported, though probably more database vendors will be targeted soon. 

For Microsoft Fabric's data engineers, data scientists and data warehouse professionals this feature is huge as importance because they don't need to care anymore about making the data available in Microsoft Fabric, which involves a considerable amount of work. 

Usually, at least for flexibility, transparence, performance and standardization, data professionals prefer to extract the data 1:1 from the source systems into a landing zone in the data warehouse or data/delta lake from where the data are further processed as needed. One data pipeline is thus built for every table in scope, which sometimes is a 10–15-minute effort per table, when the process is standardized, though upon case the effort is much higher if troubleshooting (e.g. data type incompatibility or support) or further logic changes are involved. Maintaining such data pipelines can prove to be costly over time, especially when periodic changes are needed. 

Microsoft lists other downsides of the ETL approach - restricted access to data changes, friction between people, processes, and technology, respectively the effort needed to create the pipelines, and the time needed for importing the data [1]. There's some truth is each of these points, though everything is relative. For big tables, however, refreshing all the data overnight can prove to be time-consuming and costly, especially when the data don't lie within the same region, respectively data center. Unless the data can be refreshed incrementally, the night runs can extend into the day, will all the implications that derive from this - not having actual data, which decreases the trust in reports, etc. There are tricks to speed up the process, though there are limits to what can be done. 

With mirroring, the replication of data between data sources and the analytics platform is handled in the background, after an initial replication, the changes in the source systems being reflected with a near real-time latency into OneLake, which is amazing! This allows building near real-time reporting solutions which can help the business in many ways - reviewing (and correcting in the data source) records en masse, faster overview of what's happening in the organizations, faster basis for decision-making, etc. Moreover, the mechanism is fully managed by Microsoft, which is thus responsible for making sure that the data are correctly synchronized. Only from this perspective 10-20% from the effort of building an analytics solution is probably reduced.

Mirroring in Microsoft Fabric (adapted after [2])

According to the documentation, one can replicate a whole database or choose individual regular tables (currently views aren't supported [3]), stop, restart, or remove a table from a mirroring. Moreover, through sharing, users can grant to other users or groups of users access to a mirrored database without giving access to the workspace and the rest of its items [1]. 

The data professionals and citizens can write then cross-database queries against the mirrored databases, warehouses, and the SQL analytics endpoints of lakehouses, combining data from all these sources into a single T-SQL query, which opens lot of opportunities especially in what concerns the creation of an enterprise semantic model, which should be differentiated from the semantic model created by default by the mirroring together with the SQL analytics endpoint.

Considering that the data is replicated into delta tables, one can take advantage of all the capabilities available with such tables - data versioning, time travel, interoperability and/or performance, respectively direct consumption in Power BI.

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References:
[1] Microsoft Learn - Microsoft Fabric (2024) What is Mirroring in Fabric? (link)
[2] Microsoft Learn - Microsoft Fabric (2024) Mirroring Azure SQL Database [Preview] (link)
[3] Microsoft Learn - Microsoft Fabric (2024) Frequently asked questions for Mirroring Azure SQL Database in Microsoft Fabric [Preview] (link)
[4] Microsoft Fabric Updates Blog (2024) Announcing the Public Preview of Mirroring in Microsoft Fabric, by Charles Webb (link)

Microsoft Fabric: Dataflows Gen2 (Notes)

Disclaimer: This is work in progress intended to consolidate information from various sources. 
Last updated: 10-Mar-2024

Dataflow (Gen2) Architecture [4]

Dataflow (Gen2) 

•  new generation of dataflows that resides alongside the Power BI Dataflow (Gen1) [2]
• brings new features and improved experience [2]
• similar to Dataflow Gen1 in Power BI [2]
• allows to 
• extract data from various sources
• transform it using a wide range of transformation operations 
• load it into a destination [1]
• {goal} provide an easy, reusable way to perform ETL tasks using Power Query Online [1]
• allows to promote reusable ETL logic 
• ⇒ prevents the need to create more connections to the data source.
• offer a wide variety of transformations
• can be horizontally partitioned
• {component} Lakehouse 
• used to stage data being ingested
• {component} Warehouse 
• used as a compute engine and means to write back results to staging or supported output destinations faster
• {component} Mashup Engine
• extracts, transforms, or loads the data to staging or data destinations when either [4]
• Warehouse compute cannot be used [4]
• staging is disabled for a query [4]
• {operation} creating a dataflow
• can be created in a
• Data Factory workload
• Power BI workspace
• Lakehouse
• {operation} publishing a dataflow
• generates dataflow's definition  
• ⇐ the program that runs once the dataflow is refreshed to produce tables in staging storage and/or output destination [4]
• used by the dataflow engine to generate an orchestration plan, manage resources, and orchestrate execution of queries across data sources, gateways, and compute engines, and to create tables in either the staging storage or data destination [4]
• saves changes and runs validations that must be performed in the background [2]
• {operation} refreshing a dataflow
• {operation} running a dataflow 
• can be run
• manually
• on a refresh schedule
• as part of a Data Pipeline orchestration
• {feature} author dataflows with Power Query
• uses the full Power Query experience of Power BI dataflows [2]
• {feature} shorter authoring flow
• uses step-by-step for getting the data into your the dataflow [2]
• the number of steps required to create dataflows were reduced [2]
• a few new features were added to improve the experience [2]
• {feature} Auto-Save and background publishing
• changes made to a dataflow are autosaved to the cloud (aka draft version of the dataflow) [2]
• ⇐ without having to wait for the validation to finish [2]
• {functionality} save as draft 
• stores a draft version of the dataflow every time you make a change [2]
• seamless experience and doesn't require any input [2]
• {concept} published version
• the version of the dataflow that passed validation and is ready to refresh [5]
• {feature} integration with data pipelines
• integrates directly with Data Factory pipelines for scheduling and orchestration [2] 
• {feature} high-scale compute
• leverages a new, higher-scale compute architecture [2] 
•  improves the performance of both transformations of referenced queries and get data scenarios [2]
• creates both Lakehouse and Warehouse items in the workspace, and uses them to store and access data to improve performance for all dataflows [2]
• {feature} improved monitoring and refresh history
• integrate support for Monitoring Hub [2]
• Refresh History experience upgraded [2]
• {feature} get data via Dataflows connector
• supports a wide variety of data source connectors
• include cloud and on-premises relational databases
• {feature|planned} incremental refresh 
• enables you to incrementally extract data from data sources, apply Power Query transformations, and load into various output destinations [5]
• {feature|planned} Fast Copy 
  • enables large-scale data ingestion directly utilizing the pipelines Copy Activity capability [6]
  • supports sources such Azure SQL Databases, CSV, and Parquet files in Azure Data Lake Storage and Blob Storage [6]
  • significantly scales up the data processing capacity providing high-scale ELT capabilities [6]
• {feature|planned}Cancel refresh
• enables to cancel ongoing Dataflow Gen2 refreshes from the workspace items view [6]
• {feature} data destinations
• allows to 
• specify an output destination
• separate ETL logic and destination storage [2]
• every tabular data query can have a data destination [3]
• available destinations
• Azure SQL databases
• Azure Data Explorer (Kusto)
• Fabric Lakehouse
• Fabric Warehouse
• Fabric KQL database
• a destination can be specified for every query individually [3]
• multiple different destinations can be used within a dataflow [3]
• connecting to the data destination is similar to connecting to a data source
• {limitation} functions and lists aren't supported
• {operation} creating a new table
• {default} table name has the same name as the query name.
• {operation} picking an existing table
• {operation} deleting a table manually from the data destination 
• doesn't recreate the table on the next refresh [3]
• {operation} reusing queries from Dataflow Gen1
• {method} export Dataflow Gen1 query and import it into Dataflow Gen2
• export the queries as a PQT file and import them into Dataflow Gen2 [2]
• {method} copy and paste in Power Query
• copy the queries and paste them in the Dataflow Gen2 editor [2]
• automatic settings:
• {limitation} supported only for Lakehouse and Azure SQL database
• {setting} Update method replace: 
• data in the destination is replaced at every dataflow refresh with the output data of the dataflow [3]
• {setting} Managed mapping: 
• the mapping is automatically adjusted when republishing the data flow to reflect the change 
• ⇒ doesn't need to be updated manually into the data destination experience every time changes occur [3]
• {setting} Drop and recreate table: 
• on every dataflow refresh the table is dropped and recreated to allow schema changes
• {limitation} the dataflow refresh fails if any relationships or measures were added to the table [3]
• update methods
• {method} replace: 
• on every dataflow refresh, the data is dropped from the destination and replaced by the output data of the dataflow.
• {limitation} not supported by Fabric KQL databases and Azure Data Explorer 
• {method} append: 
• on every dataflow refresh, the output data from the dataflow is appended (aka merged) to the existing data in the data destination table (aka upsert)
• staging 
• {default} enabled
• allows to use Fabric compute to execute queries
• ⇐ enhances the performance of query processing
• the data is loaded into the staging location
• ⇐ an internal Lakehouse location accessible only by the dataflow itself
• [Warehouse] staging is required before the write operation to the data destination
• ⇐ improves performance
• {limitation} only loading into the same workspace as the dataflow is supported
•  using staging locations can enhance performance in some cases
• disabled
• {recommendation} [Lakehouse] disable staging on the query to avoid loading twice into a similar destination
• ⇐ once for staging and once for data destination
• improves dataflow's performance
• {scenario} use a dataflow to load data into the lakehouse and then use a notebook to analyze the data [2]
• {scenario} use a dataflow to load data into an Azure SQL database and then use a data pipeline to load the data into a data warehouse [2]
• {benefit} extends data with consistent data, such as a standard date dimension table [1]
• {benefit} allows self-service users access to a subset of data warehouse separately [1]
• {benefit} optimizes performance with dataflows, which enable extracting data once for reuse, reducing data refresh time for slower sources [1]
• {benefit} simplifies data source complexity by only exposing dataflows to larger analyst groups [1]
• {benefit} ensures consistency and quality of data by enabling users to clean and transform data before loading it to a destination [1]
• {benefit} simplifies data integration by providing a low-code interface that ingests data from various sources [1]
• {limitation} not a replacement for a data warehouse [1]
• {limitation} row-level security isn't supported [1]
• {limitation} Fabric or Fabric trial capacity workspace is required [1]

Feature	Data flow Gen2	Dataflow Gen1
Author dataflows with Power Query	✓	✓
Shorter authoring flow	✓
Auto-Save and background publishing	✓
Data destinations	✓
Improved monitoring and refresh history	✓
Integration with data pipelines	✓
High-scale compute	✓
Get Data via Dataflows connector	✓	✓
Direct Query via Dataflows connector		✓
Incremental refresh	✓*
Fast Copy	✓*
Cancel refresh	✓*
AI Insights support		✓

Dataflow Gen1 vs Gen2 [2]

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Acronyms:
ETL - Extract, Transform, Load

KQL - Kusto Query Language
PQO - Power Query Online
PQT - Power Query Template

References:
[1] Microsoft Learn: Fabric (2023) Ingest data with Microsoft Fabric (link)
[2] Microsoft Learn: Fabric (2023) Getting from Dataflow Generation 1 to Dataflow Generation 2 (link)
[3] Microsoft Learn: Fabric (2023) Dataflow Gen2 data destinations and managed settings (link)
[4] Microsoft Learn: Fabric (2023) Dataflow Gen2 pricing for Data Factory in Microsoft Fabric (link)
[5] Microsoft Learn: Fabric (2023) Save a draft of your dataflow (link)
[6] Microsoft Learn: Fabric (2023) What's new and planned for Data Factory in Microsoft Fabric (link)

Resources:
[R1] Arshad Ali & Bradley Schacht (2024) Learn Microsoft Fabric (link)
[R2] Microsoft Learn: Fabric (2023) Data Factory limitations overview (link)
[R3] Microsoft Fabric Blog (2023) Data Factory Spotlight: Dataflow Gen2, by Miguel Escobar (link)
[R4] Microsoft Learn: Fabric (2023) Dataflow Gen2 connectors in Microsoft Fabric (link) 
[R5] Microsoft Learn: Fabric (2023) Pattern to incrementally amass data with Dataflow Gen2 (link)
[R6] Fourmoo (2004) Microsoft Fabric – Comparing Dataflow Gen2 vs Notebook on Costs and usability, by Gilbert Quevauvilliers (link)
[R7] Microsoft Learn: Fabric (2023) A guide to Fabric Dataflows for Azure Data Factory Mapping Data Flow users (link)
[R8] Microsoft Learn: Fabric (2023) Quickstart: Create your first dataflow to get and transform data (link)
[R9] Microsoft Learn: Fabric (2023) Microsoft Fabric decision guide: copy activity, dataflow, or Spark (link)
[R10] Microsoft Fabric Blog (2023) Dataflows Gen2 data destinations and managed settings, by Miquella de Boer  (link)
[R11] Microsoft Fabric Blog (2023) Service principal support to connect to data in Dataflow, Datamart, Dataset and Dataflow Gen 2, by Miquella de Boer (link)
[R12] Chris Webb's BI Blog (2023) Fabric Dataflows Gen2: To Stage Or Not To Stage? (link)
[R13] Power BI Tips (2023) Let's Learn Fabric ep.7: Fabric Dataflows Gen2 (link)

Notes: Team Data Science Process (TDSP)

Team Data Science Process (TDSP)
• an agile, iterative data science methodology to deliver predictive analytics solutions and intelligent applications efficiently [1]
• {goal} help customers fully realize the benefits of their analytics program [1]
• {component} data science lifecycle definition
  • {description} a framework to structure the development of data science projects [1]
  • {goal} designed for data science projects that ship as part of intelligent applications that deploy ML & AI models for predictive analytics [1]
  • {benefit} can be used in the context of other DM methodologies as they have common ground [1]
    • e.g. CRISP-DM, KDD
  • {benefit} exploratory data science projects or improvised analytics projects can also benefit from using this process [1]
• {component} standardized project structure
  • {description} a directory structure that includes templates for project documents
    • ⇒makes it easy for team members to find information [1]
    • ⇐templates for the folder structure and required documents are provided in standard locations [1]
    • all code and documents are stored in an agile VCS tracking repository [1]
      • {recommendation} create a separate repository for each project on the VCS for versioning, information security, and collaboration [1]
  • {benefit} organizes the code for the various activities [1]
  • {benefit} allows tracking the progress [1]
  • {benefit} provides checklist with key questions for each project to guarantee process and deliverables’ quality [1]
  • {benefit} enables team collaboration [1]
  • {benefit} allows closer tracking of the code for individual features [1]
  • {benefit} enables teams to obtain better cost estimates [1]
  • {benefit} helps build institutional knowledge across the organization [1]
• {component} recommended infrastructure
  • {description} a set of recommendations for the infrastructure and resources needed for analytics and storage [1]
  • {benefit} addresses cloud and/or on-premises requirements [1]
  • {benefit} enables reproducible analysis [1]
  • {benefit} avoids infrastructure duplication [1]
    • ⇒minimizes inconsistencies and unnecessary infrastructure costs [1]
  • {tools} tools are provided to provision the shared resources, track them, and allow each team member to connect to those resources securely [1]
  • {good practice} create a consistent compute environment [1]
    • ⇐allows team members replicate and validate experiments [1]
• {component} recommended tools and utilities
  • {description} a set of recommendations for the tools and utilities needed for project’s execution [1]
  • {benefit} help lower the barriers and increase the consistency of their adoption [1]
  • {benefit} provides an initial set of tools and scripts to jump-start methodology’s adoption [1]
  • {benefit} helps automate some of the common tasks in the data science lifecycle [1]
    • e.g. data exploration and baseline modeling [1]
  • {benefit} well-defined structure provided for individuals to contribute shared tools and utilities into their team's shared code repository [1]
    • ⇐ resources can then be leveraged by other projects [1]
• {phase} 1: business understanding
  • {goal} define and document the business problem, its objectives, the needed attributes, and the metric(s) used to determine project’s success
  • {goal} identify and document the relevant data sources
  • {step} 1.1: define project’s objectives
    • elicit together with the stakeholders the requirements, define and document the problem and its objectives, respectively the metric(s) used to determine project’s success
      • requires a good understanding of the business processes, data and further characteristics
  • {step} 1.2: identify data sources
    • identify the attributes and the data sources relevant to the problem under study
  • {step} 1.3: define project plan and team*
    • develop a high-level milestone plan and identify the resources needed for executing it
  • {tool} project charter
    • standard template that documents the business problem, the scope of the project, the business objectives and metric(s) used to determine project’s success
• {phase} 2: data acquisition & understanding
  • {goal} prepare the base dataset(s) as needed by the modeling phase into the target repository
  • {goal} build the data ETL/ELT architecture and processes needed for provisioning the basis data
  • {step} 2.1: ingest data
    • make the required data available for the team in the repository where the analytics operations take place
  • {step} 2.2: explore data
    • understand data’s characteristics by leveraging specific tools (visualization, analysis)
    • prepare the data as needed for further processing
  • {step} 2.3: set up pipelines
    • build the pipelines needed for data actualization and qualitative assessment [3]
    • set up a process to score new data or refresh the data regularly [3]
  • {step} 2.4: feasibility analysis*
    • reevaluate the project to determine whether the value expected is sufficient to continue pursuing it
  • {tool} data quality report
    • report that includes data summaries, data mappings, variable ranking, data qualitative assessment(s) and further information [3]
  • {tool} solution architecture
    • diagram and/or textual-based description of the data pipeline(s), technical assumptions and further aspects
  • {tool} data reports
    • document the structure and statistics of the raw data
  • {tool} checkpoint decision
    • decision template document that
      • summarizes the findings of the feasibility analysis step
      • includes a set of choices and recommendations for the next steps
      • serves as basis for the decision on whether to continue or not the project, respectively what the next steps are
• {phase} 3: modeling
  • {goal} create a machine-learning model that addresses the prediction requirements and that's suitable for production
  • {step} 3.1: feature engineering
    • the inclusion, aggregation, and transformation of raw variables to create the features used in the analysis [4]
      • ⇐requires a good understanding of how the features relate to each other and how the ML algorithms use those features [4]
  • {step} 3.2: model selection*
    • choose one or more modeling algorithms that address problem’s characteristics the best
  • {step} 3.3: model training
    • involves the following steps:
      • split the input data into training and test datasets
      • build the models by using the training dataset
      • evaluate the training and the test data set
      • determine the optimal setup and methods
  • {step} 3.4: model evaluation
    • evaluate the performance of the model(s)
  • {step} 3.5: feasibility analysis*
    • evaluate the readiness of the models for use into production, respectively on whether they fulfill project’s objectives
  • {tool} feature sets
    • describe the features developed for the modeling and how they were generated
    • contains pointers to the code used to generate the features
  • {tool} model report
    • a standard, template-based report that provides details on each experiment’s outcomes
    • created for each model tried
  • {tool} checkpoint decision
  • {tool} model performance metrics
    • e.g. ROC curves or MSE
• {phase} 4: deployment
  • {goal} deploy the models and the data pipelines to the environment used for final user acceptance
  • {step} 4.1: operationalize architecture
    • prepare the models and data pipelines for use into production
    • {best practice} expose the models over an open API interface
      • enables models’ consumption from various applications
    • {best practice} build telemetry and monitoring into the models and the data pipelines [5]
      • helps in monitoring and troubleshooting [5]
  • {step} 4.2: deploy solution*
    • deploy the architecture into production
  • {tool} status dashboard
    • displays data on system’s health and key metrics
  • {tool} model report
    • the report in its final form with deployment information
  • {tool} solution architecture
    • the document in its final form
• {phase} 5: customer acceptance
  • {goal} confirm that project’s objectives were fulfilled and get customer’s acceptance
  • {step} 5.1: system validation
    • validate system’s performance and outcomes and confirm that it fulfills customer’s needs
  • {step} 5.2: project signoff*
    • finalize and review documentation
    • handover the solution and afferent documentation to customer
    • evaluate the project against the defined objectives and get customer’ signoff
  • {tool} exit report
  • {tool} technical report
    • contains all the details of the project that are useful for learning about how to operate the system [6]

Acronyms:

Artificial Intelligence (AI)

Cross-Industry Standard Process for Data Mining (CRISP-DM)

Data Mining (DM)

Knowledge Discovery in Databases (KDD)

Team Data Science Process (TDSP) 

Version Control System (VCS)

Visual Studio Team Services (VSTS)

Resources:

[1] Microsoft Azure (2020) What is the Team Data Science Process? [source]

[2] Microsoft Azure (2020) The business understanding stage of the Team Data Science Process lifecycle [source]

[3] Microsoft Azure (2020) Data acquisition and understanding stage of the Team Data Science Process [source]

[4] Microsoft Azure (2020) Modeling stage of the Team Data Science Process lifecycle [source] 

[5] Microsoft Azure (2020) Deployment stage of the Team Data Science Process lifecycle [source]

[6] Microsoft Azure (2020) Customer acceptance stage of the Team Data Science Process lifecycle [source]

Microsoft Azure: Azure Data Factory (Notes)

Azure Data Factory (ADF)
• {definition} pay-per-use serverless cloud-based data integration service that orchestrates and automates the movement and transformation of both cloud-based and on-premises data sources [1]
  • ⇐ a hybrid and scalable data integration service for Big Data and advanced end-to-end analytics solutions [11]
  • ⇐ Microsoft Azure PaaS offering for ETL/ELT workloads found at its second generation [11]
  • allows creating data-driven flows to orchestrate movement of data between supported data stores and processing of data using compute services in other regions or in an on-premises environment
• {benefit} easy-to-use
  • {feature} allows creating code-free pipelines with drag-and-drop functionality [2]
  • {feature} uses JSON to describe each of its entities
• {benefit} cost-effective
  • pay-as-you-go model against the Azure subscription with no up-front costs
  • low price-to-performance ratio
    • ⇐ cost effective and performant at the same time
  • fully managed serverless cloud service that scales on demand [2]
    • ⇒requires zero hardware maintenance [1]
    • ⇒can easily scale beyond what was originally anticipated [1]
  • does not store any data [1]
  • provides additional cost-saving functionality [11]
    • {feature} it takes care of the provisioning and teardown of the cluster once the job has executed [11]
• {benefit} powerful
  • allows ingesting on-premise and cloud-based data sources
  • high-performance hybrid connectivity
    • over 90 built-in connectors make it easy to interact with all kinds of technologies [11]
  • orchestrate at scale
    • on-demand compute
    • Big Data workloads are scaled over multiple nodes to chunk data in parallel [11]
  • {feature} [ADFv2] monitoring
    • richer and natively integrating it with Azure Monitor and OMS [11]
      • includes feature-rich monitoring and management tools to visualize the current state of data pipelines, data lineage and pipeline dependencies [1]
  • {feature} [ADFv2] control flow functionality
    • lets define complex workflows using programmatic or UI mechanisms
      • allows defining parameters at pipeline level [11]
      • includes custom state passing and looping containers [11]
      • pipelines can be authored via additional tools
        • e.g. PowerShell, .NET, Python, REST APIs
        • ⇒ helps ISVs build SaaS-based analytics solutions on top of ADF app models
• {benefit} intelligent
  • autonomous ETL allows unlocking operational efficiencies and enable citizen integrators [2]
• {benefit} enterprise-grade security:
  • provides same security standards as any other Microsoft service [11]
• {benefit} monthly release cycle
  • {feature} via auto-update
  • improvements may include support for new connectors, bug fixes, security patches, and performance improvements [11]
• {benefit} backwards compatibility
  • {feature} [ADFv2] allows rehosting SSIS solutions [2]
    • ⇒ helpful for modernizing data warehouse solutions
• {prerequisite} an Azure subscription with the contributor role assigned to at least one resource group
• {limitation} availability
  • the service isn’t available in all regions
    • an instance can be made available in other region to trigger the job on customer’s computer environment [1]
      • ⇐ the time for executing the job on the compute environment doesn’t change [1]
• {concept} activity
  • the unit of orchestration in ADF [1]
  • defines the actions to perform on data [1]
  • takes zero or more datasets as inputs and produces one or more datasets as outputs [1]
  • activity types
    • data movement activities
    • data transformation activities
    • control activities
      • control how the pipeline works and interacts with the data [10]
      • allow executing pipelines [10]
      • allow running a foreach statement or Lookup activities [10]
• {concept] pipeline
  • logical grouping of activities that together perform a task [1]
    • the sequence can have a complex schedule and dependencies that need to be orchestrated and automated [1]
    • two activities can be chained by setting the output data set of one activity as the input dataset of the other activity
  • allows building ETL/ELT workloads
  • scheduled by scheduler triggers [10]
  • data in a pipeline is referred to by different names
    • ⇐ based on the amount of modification that has been performed
    • raw data
      • data with no processing applied [10]
        • ⇒does not yet have a schema applied
      • stored in the message encoding format used to send tracking events such as JSON.
      • can be organized into meaningful data stores and data lakes [10]
        • ⇐ further used in decision-making
      • it's common to send all tracking events as raw events
        • ⇐ because all events can be sent to a single endpoint and schemas can be applied later in the pipeline [10]
    • processed data
      • raw data that has been decoded in the event-specific formats with the schema applied
        • e.g. JSON tracking events that have been translated into a session start event with a fixed schema [10]
      • usually stored in different event tables and destination in a data pipeline [10]
    • cooked data
      • processed data that has been aggregated or summarized [10]
  • {concept} pipeline parameters
    • similar to SSIS package parameters
      • ⇐ need to be set from outside packages
    • can be passed from the parent pipeline
• {concept} dataset
  • named references/pointers to the data used as an input or an output of an activity [1]
  • identifies data structures within different (linked) data stores [1]
    • ⇐ before creating a dataset, a linked service must be created to link the data store to ADF [10]
    • once created, it can be used with activities in a pipeline [10]
      • e.g. a dataset can be an input or output dataset of a copy activity
• {concept} linked service
  • defines the information needed by ADF to connect to external resources at runtime
    • much like connection strings which define the connection information [10]
  • used to represent
    • {concept} data store
      • holds the input-output data to the ADF
      • e.g. tables, files, folders, and documents
    • {concept} compute resource
      • can host the execution of an activity [1]
• {concept} scheduler triggers
  • allow pipelines to be triggered on a wall-clock schedule [10]
    • pipelines and triggers have an n-m relationship
      • multiple triggers can kick off a single pipeline
      • the same trigger can kick off multiple pipelines
    • manual triggers trigger pipelines on demand [10]
  • once defined, it must be started to begin triggering the pipeline [10]
  • comes into effect only after publishing the solution to ADF [10]
    • ⇐ not when saving the trigger in the UI [10]
  • to run a pipeline, a pipeline reference must be included in trigger definition [10]
  • there is a cost associated with each pipeline run
    • {recommendation} when testing, make sure that the pipeline is triggered only a couple of times [10]
    • {recommendation} ensure that there is enough time for the pipeline to run between the published time and the end time [10]

Acronyms:

Azure Data Factory (ADF)

Continuous Integration/Continuous Deployment (CI/CD)

Extract Load Transform (ELT)

Extract Transform Load (ETL)

Independent Software Vendors (ISVs)

Operations Management Suite (OMS)

pay-as-you-go (PAYG)

SQL Server Integration Services (SSIS)

Resources:

[1] Microsoft (2020) "Microsoft Business Intelligence and Information Management: Design Guidance", by Rod College

[2] Microsoft (2021) Azure Data Factory [source]

[3] Microsoft (2018) Azure Data Factory: Data Integration in the Cloud [source]

[4] Microsoft (2021) Integrate data with Azure Data Factory or Azure Synapse Pipeline [source]

[10] Coursera (2021) Data Processing with Azure [source]

[11] Sudhir Rawat & Abhishek Narain (2019) "Understanding Azure Data Factory: Operationalizing Big Data and Advanced Analytics Solutions"

Data Science: Data Pipeline/Pipelining (Definitions)

"A series of operations in an aggregation process." (MongoDb, "Glossary", 2008)

"A series of processes all in a row, linked by pipes, where each passes its output stream to the next." (Jon Orwant et al, "Programming Perl" 4th Ed., 2012)

"Description of the process workflow in sequential order." (Hamid R Arabnia et al, "Application of Big Data for National Security", 2015)

"In data processing, a pipeline is a sequence of processing steps combined into a single object. In Spark MLlib, a pipeline is a sequence of stages. A Pipeline is an estimator containing transformers, estimators, and evaluators. When it is trained, it produces a PipelineModel containing transformers, models, and evaluators." (Alex Thomas, "Natural Language Processing with Spark NLP", 2020)

"Abstract concept used to describe where work is broken into several steps which enable multiple tasks to be in progress at the same time. Pipelining is applied in processors to increase processing of machine language instructions and is also a category of functional decomposition that reduces the synchronization cost while maintaining many of the benefits of concurrent execution." (Max Domeika, "Software Development for Embedded Multi-core Systems", 2011)

"A technique that breaks an instruction into smaller steps that can be overlapped" (Nell Dale & John Lewis, "Computer Science Illuminated" 6th Ed., 2015)

[pipeline pattern:] "A set of data processing elements connected in series, generally so that the output of one element is the input of the next one. The elements of a pipeline are often executed concurrently. Describing many algorithms, including many signal processing problems, as pipelines is generally quite natural and lends itself to parallel execution. However, in order to scale beyond the number of pipeline stages, it is necessary to exploit parallelism within a single pipeline stage." (Michael McCool et al, "Structured Parallel Programming", 2012)

"A data pipeline is a general term for a process that moves data from a source to a destination. ETL (extract, transform, and load) uses a data pipeline to move the data it extracts from a source to the destination, where it loads the data." (Jake Stein)

"A data pipeline is a piece of infrastructure responsible for routing data from where it is to where it needs to go and provide any necessary transformations through that process." (Precisely) [source] 

"A data pipeline is a service or set of actions that process data in sequence. This means that the results or output from one segment of the system become the input for the next. The usual function of a data pipeline is to move data from one state or location to another."(SnapLogic) [source]

"A data pipeline is a software process that takes data from sources and pushes it to a destination. Most modern data pipelines are automated with an ETL (Extract, Transform, Load) platform." (Xplenty) [source] 

"A data pipeline is a set of actions that extract data (or directly analytics and visualization) from various sources. It is an automated process: take these columns from this database, merge them with these columns from this API, subset rows according to a value, substitute NAs with the median and load them in this other database." (Alan Marazzi)

"A source and all the transformations and targets that receive data from that source. Each mapping contains one or more pipelines." (Informatica)

"An ETL Pipeline refers to a set of processes extracting data from an input source, transforming the data, and loading into an output destination such as a database, data mart, or a data warehouse for reporting, analysis, and data synchronization." (Databricks) [source]

"Data pipeline consists of a set of actions performed in real-time or in batches, that captures data from various sources, sorting it and then moving that data through applications, filters, and APIs for storage and analysis." (EAI)