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Author: Kevin Feasel

Getting Started with Docker

Published 2019-04-15 by Kevin Feasel

Achilleus has a brief primer on Docker:

Now that we know, some basic definitions. It’s time we ask the main question! Why do I care?

There are many reasons you might wanna use Docker. I will give my perspective on why I started to learn about Docker.

I had to test my Kafka producers and consumers locally instead of deploying my code in DEV/QA even before I was sure things are working fine but also be sure that the same code, when deployed in other environments, should behave the same.

There are a few really good reasons for containers and testing is one of them.

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When Inline UDFs are Slower

Published 2019-04-15 by Kevin Feasel

Brent Ozar has been digging deep into new functionality in SQL Server 2019:

In the Froid white paper, Microsoft talked about how they were working on fixing the function problem. When I read that white paper, my mind absolutely reeled – it’s awesome work, and I love working with a database doing that kind of cool stuff. Now that 2019 is getting closer to release, I’ve been spending more time with it. Most of the time, it works phenomenally well, and it’s the kind of improvement that will drive adoption to SQL Server 2019. Here, though, I’ve specifically picked a query that runs worse only to show you that not every query will be better.
To activate Froid, just switch the compatibility level to 150 (2019), and the query runs in 1 minute, 45 seconds, or almost twice as slow. Dig into the actual plan to understand why?

Read on to learn why.

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Power BI Helper April 2019 Edition

Published 2019-04-15 by Kevin Feasel

Reza Rad announces an update to Power BI Helper:

Previously you could use Power BI Helper to connect to a model in Power BI Desktop and analyze that model, getting the list of all tables, columns, measures, alongside with measure dependency and modeling advise, and also documenting everything at the end. The good news is that now with having XMLA endpointavailable, you can connect directly to Power BI datasets in the service, and get all those functionalities with that.

Read on for the full change set.

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Safely Dropping Extended Event Sessions

Published 2019-04-15 by Kevin Feasel

Denis Gobo shows how you can drop an extended event session without risk of a “does not exist” error:

The other day someone checked in some code and every now and then the build would fail with the error

Msg 15151, Level 16, State 19, Line 51
Cannot drop the event session ‘ProcsExecutions’, because it does not exist or you do not have permission.

I decided to take a look at the code and saw what the problem was. I will recreate the code here and then show you what needs to be changed.  This post will not go into what Extended Events are, you can look that up in the SQL Server  Extended Events documentation

I like these IF NOT EXISTS checks on release scripts as that makes them re-runnable. Even if you don’t use continuous integration for release scripts, you may sometimes hit F5 one too many times.

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Intelligent Query Processing FAQ

Published 2019-04-15 by Kevin Feasel

Joe Sack answers a number of questions about intelligent query processing in SQL Server:

You have batch mode adaptive joins, but no row mode adaptive joins. Why?
Adaptive joins are more appropriate for scenarios where the join-input row count fluctuates significantly.  Batch mode assumes a higher row flow vs. an OLTP low-row typical pattern.  Row mode adaptive joins would likely be too prone to regressions.  Batch mode on rowstore opens up adaptive joins for scenarios where we estimate higher row counts for join-inputs.

There are some good questions and answers in this set.

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Azure SQL Managed Instance Public Endpoints

Published 2019-04-15 by Kevin Feasel

Danimir Ljepava announces public endpoints for Azure SQL Managed Instances:

Public endpoint, ability to connect to Azure SQL Database Managed Instance from Internet, without VPN has reached global availability today. The release of this feature will help support many new integration scenarios.
 
The public endpoint for Managed Instance can today be enabled/disabled via PowerShell script. The support for Azure portal will be coming within the next week or so as soon as all updates are rolled out.

Click through to learn how to enable it with Powershell.

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The Prevalence of Persistent XSS

Published 2019-04-12 by Kevin Feasel

Adrian Colyer has a review of a security-minded paper:

Does your web application make use of local storage? If so, then like many developers you may well be making the assumption that when you read from local storage, it will only contain the data that you put there. As Steffens et al. show in this paper, that’s a dangerous assumption! The storage aspect of local storage makes possible a particularly nasty form of attack known as a persistent client-side cross-site scripting attack. Such an attack, once it has embedded itself in your browser one time (e.g. that one occasion you quickly had to jump on the coffee shop wifi), continues to work on all subsequent visits to the target site (e.g., once you’re back home on a trusted network).

In an analysis of the top 5000 Alexa domains, 21% of sites that make use of data originating from storage were found to contain vulnerabilities, of which at least 70% were directly exploitable using the models described in this paper.

Adrian’s been on a security paper kick the last few days, so be sure to check those out.

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CSV Data Ingestion with Spark

Published 2019-04-12 by Kevin Feasel

Jean Georges Perrin shows how you can easily load CSV data with Spark:

Fortunately for you, Apache Spark offers a variety of options for ingesting those CSV files. Ingesting CSV is easy and schema inference is a powerful feature.
Let’s have a look at more advanced examples with more options that illustrate the complexity of CSV files in the outside world. You’ll first look at the file you’ll ingest, and understand its specifications. You’ll then have a look at the result and finally build the mini-application to achieve the result. This pattern repeats for each format.

It’s good to see some of the lesser-used features pop up like date format and multi-line support (which I hadn’t even known about).

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The Benefits of Partitioning in CosmosDB

Published 2019-04-12 by Kevin Feasel

Hasan Savran explains why partitioning data in CosmosDB is so important:

In any Introduction level CosmosDB talk, Presenter will suggest you pay more attention to the Partitioning part of the talk. Microsoft wants you to create great solution by using Azure CosmosDB and there are a lot of resources out there for developers. The challenge in Azure CosmosDB is, you don’t need a DBA in CosmosDB and developers may not pay attention to details like Partitioning when they create databases in Azure CosmosDB.
  
      It is crucial to pick the right partition key for your databases in CosmosDB simply because you cannot repartition your databases. If you pick a wrong partition key for your data model, it will be simply too late to change it later. You might have good amount of data in your databases, that means you spent good amount of RU to insert this data and only way to fix this problem will be start from scratch and upload all data back again to CosmosDB with the right partition key.

Read on for a couple of analogies and why this is so important.

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SSMS Autorecover

Published 2019-04-12 by Kevin Feasel

Michelle Haarhues takes us through auto-recovery in Management Studio:

Periodically there is a crash, power surge, or sudden reboot of your computer.  Of course, you had SQL Server Management Studio (SSMS) open and you were working on something important.  That seems to be the only time there is a crash/reboot.  You can lose work that that was open in SSMS but has not saved.  There is an AutoRecover feature in SSMS so all may not be lost.  

Read on to learn more about auto-recovery. It only restores on crashes, though there are third-party plugins you can get to restore after start. Azure Data Studio restores on restart as well, so kudos to the ADS team for that.

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