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Day: October 21, 2024

The Pain of fn_xe_file_target_read_file

Tom Zika plants a flag:

I haven’t had a rant post in a while. There is a saying: “Anything before the word ‘but’ is ignored”. I love Extended Events, but … reading the extended event file is so much pain.

It feels like there is a conspiracy between Microsoft and Big Pharma SQL Monitoring because the best analytics tool available in SQL Server (and I mean Extended Events and Query Store of course) have the worst GUI and supporting tools. I’m focusing on XE in this post.

Read on for Tom’s rant. To add on to it, the feedback item Tom links to now has a new update from Dimitri Furman, indicating (based on how I’m reading it) that the fix will be in SQL vNext, not SQL Server 2022.

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Bi-Directional Replication in PostgreSQL

Semab Tariq does a bit of replication:

Bi-directional replication, often referred to as multi-master replication, allows data to be written and read from multiple database nodes. This means that changes made on one node are automatically replicated to the other node, and vice versa. This setup ensures that all nodes have the same data, providing high availability and fault tolerance.

This example covers replicating a single table, but the code itself was rather easy to follow. I imagine things get a bit more challenging when you add some of the more common types of complexity to this, including what happens when your app tries to insert the same record on both nodes.

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Tips for Developing Good Tutorials

Adron Hall shares some advice on writing a tutorial (or any kind of technical documentation):

Here’s the deal, tutorial writers: lay out ALL the prerequisites clearly at the beginning. And I mean ALL of them. Don’t assume I have jq installed for your GraphQL tutorial. Don’t assume I’m running the latest version of Python (and for the love of code, specify WHICH Python – 2.x or 3.x?).

And here’s a novel idea: how about actually telling me where to find and install these prerequisites? Give me links, give me version numbers, give me command line instructions. Assume I’m starting from scratch on a fresh machine. Because guess what? Sometimes I am!

I think that the set of tips Adron provides is aspirationally solid, meaning that there may be some things you can’t actually do but you should certainly try to do all of them. And I’m certainly not perfect at this.

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Listing Columns a DAX Query Touches

Chris Webb is making a list:

Some time ago I wrote a post about how you can use the DISCOVER_CALC_DEPENDENCY DMV to get a list of all the tables, columns and relationships referenced by a DAX query. That’s really useful and indeed the new INFO.CALCDEPENDENCY DAX function allows you to do the same thing without all the complexity of calling a DMV. However this doesn’t quite give you everything you need to solve one important problem: which columns are touched when a DAX query runs? The INFO.CALCDEPENDENCY function gives you a list of all the columns used directly in a DAX query and it also gives you a list of all the columns needed by all the measures used in a DAX query. However it only gives you a list of the relationships used and these relationships also rely on columns. In this post I’ll show you how to get a list of all the columns that are touched by a DAX query.

Click through for the script.

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Dynamically Start a Child Pipeline in Fabric Data Factory

Andy Leonard continues a series on Fabric Data Factory design patterns:

In an earlier post titled Fabric Data Factory Design Pattern – Basic Parent-Child, I demonstrated one way to build a basic parent-child design pattern in Fabric Data Factory by calling one pipeline (child) from another pipeline (parent). In a later earlier post titled Fabric Data Factory Design Pattern – Parent-Child with Parameters, I modified the parent and child pipelines to demonstrate passing a parameter value from a parent pipeline when calling a child pipeline that contains a parameter.

In this post, I modify a parent pipeline to explore parameterizing which child pipeline will be called by the parent pipeline. In this post, we will:

  • Copy the child pipeline id
  • Clone a parent pipeline
  • Add and configure a pipeline variable for the child pipeline id
  • Test the dynamic pipeline id

Read on to see how.

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