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Day: August 5, 2022

Azure Databricks Initialization Scripts

Alex Crampton explains how initialization scripts work in Azure Databricks:

This blog will demonstrate the use of cluster-scoped initialisation scripts for Azure Databricks. An example will run through how to configure an initialisation script to install libraries on to a cluster that are not included in the Azure Databricks runtime environment. It will cover how to do this firstly using the Databricks UI, followed by how to include it in your CI/CD solutions.

Read on for some examples.

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Security Practices for Delta Sharing

Andrew Weaver, et al, share some advice:

When you enable Delta Sharing, you configure the token lifetime for recipient credentials. If you set the token lifetime to 0, recipient tokens never expire.

Setting the appropriate token lifetime is critically important for regulatory, compliance and reputational standpoint. Having a token that never expires is a huge risk; therefore, it is recommended using short-lived tokens as best practice. It is far easier to grant a new token to a recipient whose token has expired than it is to investigate the use of a token whose lifetime has been improperly set.

Click through for eight such tips.

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Databricks Extension for VSCode at 1.0

Gerhard Brueckl shares the good news:

As you probably know from my previous posts, my colleagues at and I are constantly working to improve our VSCode extension for Databricks. Almost every month we silently release a new version to the VSCode gallery so you get the latest features. However, as this is a special release, I am also writing a dedicated blog post for it

There’s a lot of cool stuff in here, so check it out.

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Z-Ordering with Apache Impala

Zoltan Borok-Nagy and Norbert Luksa show off a performance improvement in Apache Impala:

So we’ll have great search capabilities against the partition columns plus one data column (which drives the ordering in the data files). With our sample schema above, this means we could specify a SORT BY “platform” to enable fast analysis of all Android or iOS users. But what if we wanted to understand how well version 5.16 of our app is doing across platforms and countries?

Can we do more? It turns out that we can. There are exotic orderings out there that can also sort data by multiple columns. In this post, we will describe how Z-order allows ordering of multidimensional data (multiple columns) with the help of a space-filling curve. This ordering enables us to efficiently search against more columns. More on that later.

It looks like a really good technique for nearly-static data, sort of like you’d see with a data warehouse which refreshes once a day.

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Apache eCharts for Python

Mark LItwintschik looks at another charting library:

The Apache eCharts project is a web-based charting library. It was started in 2013 and built using 77.5K lines of TypeScript. It is well documented and has over 200 examples of its API’s usage. The examples allow you to toggle between light/dark mode and there is a cheat sheet and a theme builder with several tasteful presents to choose from.

This is a library I hadn’t heard of before but Mark shows it off a bit.

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PSWorkItems: Powershell TODOs

Jeffrey Hicks has a new module:

I spend my working days living in a PowerShell console. Over the years, I’ve developed many PowerShell modules to help me manage the chaos that is my work life. One area that always demands attention is managing my tasks and To-Dos. For several years I have been using the MyTasks module. This module stored tasks and supporting information in a set of XML files. The code in the module treated the XML files as databases. I was trying to avoid a dependency on a SQL Server Express installation with the idea that would be overkill.

ln the meantime, I finally got around to finishing and publishing the MySQLite PowerShell module. This module has a set of PowerShell functions designed to simplify working with SQLite database files. This type of database has a much smaller footprint than SQL Server Express and would streamline my task management.

Click through to see how it works.

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Why Transaction Log Backup Chains Break

Tom Collins enumerates several reasons for a transaction log backup chain breaking:

The SQL Server transaction log backup chain aka log chain is the series of sequential transaction log backups related to a database. The log backups are related to each other and are represented through LSN . Breaking the transaction log chain will limit the restore point of the backups. 

Click through for four such reasons as well as a scenario explaining how it could happen.

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Preventing Data Exfiltration form Managed Instances

Niko Neugebauer wants to hang on to that data:

Data exfiltration is a technique that is also sometimes described as data theft or data extrusion, that describes the unauthorized extraction of data from the original source. This unauthorized extraction can be executed either manually or automatically by the malicious attacker.

As part of your Network Infrastructure, you might have tightened your security to make sure you have all the bells and whistles to lock down your Azure SQL Managed Instance to be accessed only by your application and not exposed to the Internet or any other traffic. However, this doesn’t stop a malicious admin from taking a backup or creating a linked server to another resource outside your enterprise subscription for extracting the data. This action would be data exfiltration. In a typical on-premises infrastructure, you can lock down network access completely to make sure that the data never leaves your network. However, in a cloud setup, there is a possibility that someone with elevated privileges can export data or perform some other malicious activity targeting their own resources outside your organization, compromising your enterprise data. Hence, it is very important to understand the different data exfiltration scenarios and make sure that you are taking the right steps to monitor for and prevent such activities.

Click through for a table which shows common exfiltration scenarios and things you can do to reduce the risk of exfiltration. With access, though, there’s always going to be a risk of exfiltration: even in a SCIF, you can get away with shoving records into your pants if you’re famous enough.

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