Azure Data Lake Analytics Pipelines

Yan Li notes that Azure Data Lake Analytics now offers the ability to manage pipelines:

To make it easier to manage and understand jobs, ADLA now captures the pipeline and recurrence information for each job. This information can be used to connect and organize jobs belonging to the same pipeline or recurring instances. As shown in Fig 2, now jobs are organized by pipeline and recurring instances which enable you to:

  • Quickly identify jobs in pipelines which may have failed or taken longer than expected.

  • Get the aggregated statistics (e.g. job counts, successful and failed AU hours etc.) for a pipeline or a recurring instance

This is an interesting improvement.

Generating U-SQL Extract Scripts From Visual Studio

Yanan Cai shows a GUI for creating U-SQL EXTRACT scripts via Azure Data Lake Tools for Visual Studio:

One of U-SQL’s core capabilities is to be able to schematize unstructured data on the fly without having to create a metadata object for it. This capability is provided by the EXTRACT expression that will invoke either a user-defined extractor or built-in extractor to process the input file or set of files specified in the FROM clause and produces a rowset whose schema is specified in the EXTRACT clause.

While using the build-in extractor to schema semi-structured data, like data in .csv file, the schema definition in U-SQL is slow and error prone, especially for the .csv file contains hundreds of columns.

Recently, we released a new feature in the latest version of Azure Data Lake Tools for Visual Studio to help you generate this U-SQL EXTRACT statement automatically.

Click through for an example as well as a video showing the process.

The Data Lake From 10,000 Feet

Pradeep Menon has a high-level explanation of what a data lake is and how it differs from traditional data warehouses:

With the changes in the data paradigm, a new architectural pattern has emerged. It’s called as the Data Lake Architecture. Like the water in the lake, data in a data lake is in the purest possible form. Like the lake, it caters to need to different people, those who want to fish or those who want to take a boat ride or those who want to get drinking water from it, a data lake architecture caters to multiple personas. It provides data scientists an avenue to explore data and create a hypothesis. It provides an avenue for business users to explore data. It provides an avenue for data analysts to analyze data and find patterns. It provides an avenue for reporting analysts to create reports and present to stakeholders.

The way I compare a data lake to a data warehouse or a mart is like this:

Data Lake stores data in the purest form caters to multiple stakeholders and can also be used to package data in a form that can be consumed by end-users. On the other hand, Data Warehouse is already distilled and packaged for defined purposes.

One way of thinking about this is that data warehouses are great for solving known business questions:  generating 10K reports or other regulatory compliance reporting, building the end-of-month data, and viewing standard KPIs.  By contrast, the data lake is (among other things) for spelunking, trying to answer those one-off questions people seem to have but which the warehouse never seems to have quite the right set of information.

Data Lake Analysis With Excel And Power BI

Sachin C Sheth announces support for Azure Data Lake Store within Excel and Power BI:

Until now, if you had to analyze data stored in ADLS with Excel, you would have to copy it into a relational data store like Azure SQL Data Warehouse or download the data onto a machine, and then use Excel to analyze that data. This was rather cumbersome involving additional cost and time. With this new support, you can now access files stored in ADLS with Excel in-place, without having to copy them to other stores or locations. You can quickly get advanced insights into raw or prepared data. Models and queries you have created using Excel that ran against local data, can be run seamlessly against data stored in ADLS.

Security capabilities of ADLS allow administrators to control access to the data stored in ADLS in a discretionary manner. With this you can limit the access that Excel users have for the data in ADLS. In this manner, data in the ADLS-based data lake continues to be the single source of truth with no redundant copies and can be analyzed by analytics tools of your own choice .

Click through for a demo video.

Diving Into The Data Lake

Jesse Gorter explains the data lake metaphor:

A data lake is a concept that opposes the idea of a data mart. Where a data mart is a silo with structured and cleansed data, a data lake is a huge data collection that is unstructured and raw. You could also say that a data mart is a bottle of clean water whereas the data lake is the lake with (not so clean) water. 🙂

Now why would you want a data lake? Imagine you are generating huge logfiles, for example in airplanes. Machines that track air pressure, temperature etc. If something goes wrong, you definitely want to be alerted. That is event-driven: “if A and B happen, alert pilot, or do C” and there are tools for dealing with that kind of streaming data. But what if the plane landed safely? What do you do with all that data? You do not need it anymore right?

Well, some people would say: “Wrong”. You might need that data later for reasons you do not know today. Google, Microsoft and Facebook are all hoarding data. Also data they are not sure they might need someday. This data could later prove to be valuable for AI, machine learning or for something else.

Read the whole thing.  The data lake concept is powerful, but it requires at least as much data governance as prior models.  Just because you can dump a bunch of files without thinking about it doesn’t mean you’ll get back something useful later.

Data Lake Tools For VS Code Updated

Jenny Jiang announces Azure Data Lake Tools for Visual Studio Code’s July update:

Local Debug enables you to debug your C# code behind, step through the code, and validate your script locally before submitting to ADLA.

  • Use command ADL: Start Local Run Service to start local run service and set a breakpoint in your code behind, then click command ADL: Local Debug to start local debug service. You can debug through the debug console and view parameter, variable, and call stack information.

Click through to see the other improvements.

Thinking About The Data Lake

James Serra explains at a high level what the data lake metaphor is and how it works:

The data lake introduces a new data analysis paradigm shift:

OLD WAY: Structure -> Ingest -> Analyze

NEW WAY: Ingest -> Analyze -> Structure

This allows you to avoid a lot of up-front work before you are able to analyze data.  With the old way, you have to know the questions to ask.  The new way supports situations when you don’t know the questions to ask.

This solves the two biggest reasons why many EDW projects fail:

  • Too much time spent modeling when you don’t know all of the questions your data needs to answer

  • Wasted time spent on ETL where the net effect is a star schema that doesn’t actually show value

There are some good details here.  My addition would be to reiterate the importance of a good data governance policy.

Managing Data Lake Analytics Compute

Yan Li has a three-part series looking at management of Azure Data Lake compute.  First, an overview:

Scenario 2: Set One Specific Group to Different Limits

New members are joining and sharing the same ADLA account. To prevent any new members, who are just learning ADLA, from mistakenly submitting a job that consumes too much compute resource (increasing cost and blocking other jobs), customers want to set the maximum AU per job for new employees at 30 AUs while others can submit jobs with up to 100 AUs.

Default Policy:

  • Job AU limit: 100
  • Priority limit: 1

Exception Policy: New Employee Policy

  • Job AU limit: 30

  • Priority limit:  200

  • Group: New Employee Group

Next up is a look at job-level policies:

With job-level policies, you can control the maximum AUs and the maximum priority that individual users (or members of security groups) can set on the jobs that they submit. This allows you to not only control the costs incurred by your users but also control the impact they might have on high priority production jobs running in the same ADLA account.

There are two parts to a job level policy:

  • Default Policy: This is the policy that is applied to all users of the service.
  • Exceptions: The set of “exception” policies apply to specific users.

Submitted jobs that do not violate the job-level policies are still subject to the account level policies as described in Azure Data Lake Analytics Account Level Policy.

Finally, account-level policies:

ADLA supports three types of account-level policies:

  • Maximum AUs  — Controls the maximum number of AUs that can be used by running jobs

  • Maximum Number of Running Jobs  — Controls the maximum number of concurrently running jobs.

  • Days to Retain Job Queries  — Controls how long detailed information about jobs are retained in the users ADLS account.

There’s a good amount of information here.

Jupyter + Pandas On Azure Data Lake Store

Amit Kulkarni demonstrates how to access data in Azure Data Lake Store within a Jupyter notebook:

For the rest of this post, I assume that you have some basic familiarity with Python, Pandas and Jupyter.

On your machine, you will need all of the following installed:

  1. Python 2 or 3 with Pip

  2. Pandas

  3. Jupyter

Amit shows two separate methods for retrieving data, so check it out.

Azure Data Lake Tools For VS Code

Jenny Jiang announces that Azure Data Lake Tools for Visual Studio Code is now generally available:

ADLA Integration

The ADL Tools for VSCode integrate well with ADLA. Azure Data Lake includes the capabilities required to make it easy for developers, data scientists, and analysts to store data of any size, shape, and speed, and do all types of processing and analytics across platforms and languages. U-SQL on ADLA offers Job as a Service with the Microsoft invented U-SQL language. Customers do not have to manage deployment of clusters, but can simply submit their jobs to ADLA, an analytics platform managed by Microsoft.

Click through for the full announcement.

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