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Day: September 15, 2023

Reading Parquet Files with DuckDB and R

Michaël read a Parquet file:

Querying a remote parquet file via HTTP with DuckDB.

The french statistical service (INSEE) has made available its first parquet file on in June.

It’s a 470 MB file (from a 1.8 GB CSV) with 16·106 rows, showing for each address in France which polling station it belongs to.

Click through for the code and results. The only thing which surprised me at all was that the performance was so fast for a remote file, unless I’m misunderstanding something. For a local file, I’d expect 16 million rows to complete in under 2 seconds for heavy aggregation on two columns in Parquet. H/T R-Bloggers.

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Multi-Plot Graphs in R

Steven Sanderson needs more than one line:

Data visualization is a crucial aspect of data analysis. In R, the flexibility and power of its plotting capabilities allow you to create compelling visualizations. One common scenario is the need to display multiple plots on the same graph. In this blog post, we’ll explore three different approaches to achieve this using the same dataset. We’ll use the set.seed(123) and generate data with x and y equal to cumsum(rnorm(25)) for consistency across examples.

Click through for three common techniques.

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An Overview of Microsoft Fabric Domains

Reza Rad provides an overview:

Microsoft Fabric introduced a new concept called Domains. Domains are more than just a separation of Fabric data items. They come with a whole lot of security, administration, and governance features, which brings the concept of data mesh into the world of data analytics using Microsoft Fabric. Domains are logical categorizations inside the OneLake. In this article and video, I will explain what domains are in Microsoft Fabric, why they are important, and their associated features and configurations.

Click through for both a video on the topic and a lengthy article.

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Heap-Only Tuples in Postgres

Umair Shahid explains the benefit of Heap-Only Tuples in PostgreSQL:

Heap-only tuples, also known as HOT, are PostgreSQL’s answer to the update query performance issues caused by MVCC. These tuples allow PostgreSQL to mark a row as “dead” and physically reuse the space it occupies in the table. This process eliminates the need to keep multiple versions of the same row, reducing I/O and improving query performance.

Read on to see how these compare to the normal MVCC process in Postgres, as well as cases when you should and should not use them.

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CI/CD for Synapse Serverless SQL Pool with SqlPackage and Azure DevOps

Rui Cunha has a tutorial for us:

Azure Synapse Analytics Serverless SQL is a query service mostly used over the data in your data lake, for data discovery, transformation, and exploration purposes. It is, therefore, normal to find in a Synapse Serverless SQL pool many objects referencing external locations,  using disparate external data sources, authentication mechanisms, file formats, etc. In the context of CICD,  where automated processes are responsible for propagating the database code across environments, one can take advantage of database oriented tools like SSDT and SqlPackage CLI , ensuring that this code is conformed with the targeted resources.

In this article I will demonstrate how you can take advantage of thee tools when implementing the CICD for the Azure Synapse Serverless SQL engine. We will leverage SQL projects in SSDT to define our objects and implement deploy-time variables (SQLCMD variables).  Through CICD pipelines, we will build the SQL project to a dacpac artifact, which enables us to deploy the database objects one or many times with automation.

Click through for the demonstration.

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The Search for Extended Events Information

Grant Fritchey stays on the first page:

Here’s their paraphrased (probably badly) story:

“I was working with an organization just a few weeks back. They found that Trace was truncating the text on some queries they were trying to track. I asked them if they had tried using Extended Events. They responded: What’s that? After explaining it to them, they went away for an hour or so and came back to me saying that had fixed the problem.”

We all smiled and chuckled. But then it struck me. This wasn’t a case of someone who simply had a lot more experience and understanding of Profiler/Trace, so they preferred to use it. They had literally never heard of Extended Events.


This led Grant to perform some search engine shenanigans and what he found was curious. A couple of points with search engines, though:

  • Search engine results will differ based on your location (IP address) and whether you are signed in or not. Google is particularly selective about this stuff. It might also affect Bing, but let’s face it: if you’re using Bing to search for anything other than images, you’ve already resigned yourself to failure.
  • In my case, a search for “extended events” (without quotation marks) did show quite a few pages which I’d consider reasonable for the topic: a Microsoft Learn quickstart article on using extended events, Brent Ozar’s extended events material, a SQL Shack article on the topic, etc. A good number of these links are content from the past 5 years, as well.
  • Grant mentions the “page 1” effect in search engines, and he’s absolutely right. The vast majority of people performing a search never leave the first page of results. This is part of why Google went to an infinite scrolling approach rather than showing explicit numbered pages.
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