Press "Enter" to skip to content

Day: August 23, 2019

Comparing Performance: HBase1 vs HBase2

Published 2019-08-23 by Kevin Feasel

Surbhi Kochhar takes us through performance improvements between HBase version 1 and HBase version 2:

We are loading the YCSB dataset with 1000,000,000 records with each record 1KB in size, creating total 1TB of data. After loading, we wait for all compaction operations to finish before starting workload test. Each workload tested was run 3 times for 15min each and the throughput* measured. The average number is taken from 3 tests to produce the final number. 

The post argues that there’s an improvement, but when a majority of cases end up worse (even if just a little bit), I’m not sure it’s much of an improvement.

Comments closed

The Transaction Log in Delta Tables

Published 2019-08-23 by Kevin Feasel

Burak Yavuz, et al, explain how the transaction log works with Delta Tables in Apache Spark:

When a user creates a Delta Lake table, that table’s transaction log is automatically created in the _delta_log subdirectory. As he or she makes changes to that table, those changes are recorded as ordered, atomic commits in the transaction log. Each commit is written out as a JSON file, starting with 000000.json. Additional changes to the table generate subsequent JSON files in ascending numerical order so that the next commit is written out as 000001.json, the following as 000002.json, and so on.

It’s interesting that they chose JSON instead of a binary transaction log like relational databases use.

Comments closed

Spark for .NET Developers

Published 2019-08-23 by Kevin Feasel

Ed Elliott has a long-form post covering spark-dotnet:

The .NET driver is made up of two parts, and the first part is a Java JAR file which is loaded by Spark and then runs the .NET application. The second part of the .NET driver runs in the process and acts as a proxy between the .NET code and .NET Java classes (from the JAR file) which then translate the requests into Java requests in the Java VM which hosts Spark.

The .NET driver is added to a .NET program using NuGet and ships both the .NET library as well as two Java jars. One jar is for Spark 2.3 and one for Spark 2.4, and you do need to use the correct one on your installed version of Scala.

As much as I’ve enjoyed his series, getting it in a single-post format is great.

Comments closed

Storytelling with Power BI: Consistency

Published 2019-08-23 by Kevin Feasel

Mark Lelijveld continues a series on storytelling with Power BI:

In the below report you can easily click on a country on the left side to move to another page. When it comes to interactivity it is all done right! On the right top you can also filter on order date. Let’s say we apply a filter to only see the sales up to the end of 2013. This results in a sales amount of nearly $ 319K.

Now, Germany gets my attention. I want to see more and decide to navigate to the other page by clicking on Germany. Ending up at the other page, I see that the sales amount changes back to $2.3M. In other words, my filter is gone!

Much of the difference between adequacy and excellence with visualization is in this kind of polish.

Comments closed

Powershell Remoting in dbatools

Published 2019-08-23 by Kevin Feasel

Claudio Silva takes us through a change to several cmdlets in dbatools:

I wondered why and asked the Windows team if they could provide any insight. A colleague explained to me that I needed to change three things to make my remoting commands work on our network:

1. Use the FQDN on -ComputerName and/or -SqlInstance parameters
2. Use -UseSSL parameter on the New-PSSession command
3. Use -IncludePortInSPN parameter for the New-PsSessionOption command

Read the whole thing.

Comments closed

Azure Dedicated Hosts in Preview

Published 2019-08-23 by Kevin Feasel

Mine Tokus covers the benefit of Azure Dedicated Hosts:

Recently introduced, Azure Dedicated Host Preview provides single-tenant physical servers that can host one or more virtual machines. With this new hosting model, physical server is dedicated to your organization and capacity isn’t shared with other customers. Physical server-level isolation helps to address security and compliance requirements, brings visibility and control over the server infrastructure and enables significant cost savings and licensing flexibility for SQL Server workloads on Azure VMs.

I think this might get some recalcitrant large companies to be willing to adopt cloud technologies.

Comments closed

SQL Server 2019 RC1

Published 2019-08-23 by Kevin Feasel

Amit Banerjee announces SQL Server 2019 Release Candidate 1:

Today we’re announcing the availability of the first public release candidate for SQL Server 2019, which is now available for download. SQL Server 2019 brings the industry-leading performance and security of SQL Server to Windows, Linux, and containers and can tackle any data workload from business intelligence to data warehousing to analytics and AI over all your data both structured and unstructured.

Amit’s update covers the span of what we’ve seen in all of the CTPs. I went through the release notes and did not find a huge amount of detail on what went into RC1 versus CTP 3.2. But the fact that they’re up to RCs means that SQL Server 2019 is getting close to release.

Comments closed

Connecting to Redshift from Azure Analysis Services

Published 2019-08-23 by Kevin Feasel

Gilbert Quevauvilliers shows how we can connect to Amazon Redshift from Azure Analysis Services:

I am busy working with a customer and had a challenge when using Azure Analysis Services to connect to Amazon Redshift via an ODBC connection.

The first issue that I encountered was the following error: OLE DB or ODBC error: [Microsoft][ODBC Driver Manager] The specified DSN contains an architecture mismatch between the Driver and Application; AWS PROD. This lead me to a few websites and the one that got me to my solution was Tabular: Error while using ODBC data source for Importing Data

Below are the steps on how I installed, configured and got the connection and refresh working.

Read on for those steps.

Comments closed