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Month: March 2019

Building a VPC with AWS

Published 2019-03-14 by Kevin Feasel

Priyaj Kumar takes us through the process of building a Virtual Private Cloud in AWS:

AWS provides a lot of services, these services are sufficient to run your architecture. The backbone for the security of this architecture is VPC (Virtual Private Cloud). VPC is basically a private cloud in the AWS environment that helps you to use all the services by AWS in your defined private space. You have control over the virtual network and you can also restrict the incoming traffic using security groups.

Overall, VPC helps you to secure your environment and give you a complete authority of incoming traffic. There are two types of VPCs, Default VPC that is by default created by Amazon and Non-Default VPC that is created by you to suffice your security needs.

Now that you have an idea of how VPC works, I will take you through the different services offered by Amazon VPC.

Read on to see how to set one up.

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Counting Working Days with DAX

Published 2019-03-14 by Kevin Feasel

Alberto Ferrari shows how we can ignore weekends in date calculations with DAX:

How is it possible to compute the difference between the two dates, only computing working days and skipping weekends and holidays? Simple math is no longer useful here, and DAX does not offer a predefined function.

A solution to this scenario requires a date table – more details here – with a specific column, IsWorkingDay, which indicates whether that particular day is a working day or not. The following figure shows an example:

Another good use of date tables (AKA calendar tables), which are also quite useful in T-SQL queries.

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Triggering KB 4462481

Published 2019-03-14 by Kevin Feasel

Joe Obbish shows how you can recreate the error described in KB 4462481:

Consider a query execution that meets all of the following criteria:

1. A parallel INSERT INTO… SELECT into a columnstore table is performed

2. The SELECT part of the query contains a batch mode hash join

3. The query can’t immediate get a memory grant, hits the 25 second memory grant timeout and executes with required memory

The query may appear to get stuck. 

Click through for Joe’s demo. The fix? Update to SQL Server 2017 CU11.

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Workload Capture with WorkloadTools

Published 2019-03-14 by Kevin Feasel

Gianluca Sartori continues a series on WorkloadTools:

Last week I showed you how to use WorkloadTools to analyze a workload. As you have seen, using SqlWorkload to extract performance data from your workload is extremely easy and it just takes a few keystrokes in your favorite text editor to craft the perfect .json configuration file.

Today I’m going to show you how to capture a workload and save it to a file. If you’ve ever tried to perform this task with any other traditional benchmarking tool, like RML Utilities or Distributed Replay, your palms are probably sweaty already, but fear not: no complicated traces to set up, no hypertrophic scripts to create extended events captures. WorkloadTools makes it as easy as it can get.

Saving a workload to a file might look superfluous when you think that WorkloadTools has the ability to perform replays in real-time (I’ll discuss this feature in a future post), but there are situations when you want to replay the same exact workload multiple times, maybe changing something in the target database between each benchmark to see precisely what performance looks like under different conditions.

Gianluca’s technique does seem a lot less fussy than the Microsoft techniques.

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SQL Server and Ubuntu 18.04

Published 2019-03-14 by Kevin Feasel

Randolph West confirms that SQL Server on Linux will run on Ubuntu 18.04 even though it is not (yet) supported:

Although these screenshots show SQL Server 2019 preview CTP 2.3, this also applies to SQL Server 2017 on 18.04.2, because that’s what I had installed before upgrading the SQL Server version. However, as my friend Jay Falck pointed out on Twitter, Microsoft has stated publicly that it is not yet certified for production use:

Important, this does not change the support state of SQL Server 2017 on Ubuntu 18.04. Work to certify Ubuntu 18.04 with SQL Server 2017 is planned and we will announce when it will be supported for production use on this page. Until such as an announcement occurs, SQL Server 2017 on Ubuntu 18.04 should be considered experimental and for non-production use only.

Read on for Randolph’s thoughts on the issue.

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R 3.5.3 Available

Published 2019-03-13 by Kevin Feasel

David Smith shares some info on R 3.5.3, released on Monday:

The R Core Team announced yesterday the release of R 3.5.3, and updated binaries for Windows and Linux are now available (with Mac sure to follow soon). This update fixes three minor bugs (to the functions writeLines, setClassUnion, and stopifnot), but you might want to upgrade just to avoid the “package built under R 3.5.4” warnings you might get for new CRAN packages in the future.

Click through for more info on this release, including where the name from each R release comes from.

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Securely Accessing External Resources From Databricks AWS

Published 2019-03-13 by Kevin Feasel

Itai Weiss shows how you can securely hit external data sources when using Databricks for AWS:

For security purposes, Databricks Apache Spark clusters are deployed in an isolated VPC dedicated to Databricks within the customer’s account. In order to run their data workloads, there is a need to have secure connectivity between the Databricks Spark Clusters and the above data sources.

It is straightforward for Databricks clusters located within the Databricks VPC to access data from AWS S3 which is not a VPC specific service. However, we need a different solution to access data from sources deployed in other VPCs such as AWS Redshift, RDS databases, streaming data from Kinesis or Kafka. This blog will walk you through some of the options you have available to access data from these sources securely and their cost considerations for deployments on AWS. In order to establish a secure connection to these data sources, we will have to configure the Databricks VPC with either one of the following two available options :

Read on for those two options.

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Getting Started with Kubernetes

Published 2019-03-13 by Kevin Feasel

Praveen Sripati walks us through the Play with Kubernetes lab website:

There are many ways of installing K8S as mentioned here. It can be installed in the Cloud, on-premise and also locally on the laptop using virtualization. But, installing K8S had never been easy. In this blog, we will look at one of the easiest way to get started with K8S using Play with Kubernetes (PWK). With this the whole K8S experience is within the browser and there is nothing to install on the laptop, everything is installed on the remote machine. PWK uses ‘Docker in Docker’ which is detailed here (1, 2).

This looks like a really useful way to get the hang of Kubernetes before trying it out on your own machines.

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